Signal chain++

Loop condition++
Dots--
2014-01-21 12:58:11 -08:00 · 2014-01-21 12:56:54 -08:00 · 2014-01-21 12:56:00 -08:00 · 2014-01-21 12:55:57 -08:00 · 2014-01-21 12:55:28 -08:00 · 2014-01-21 12:55:22 -08:00
32 changed files with 1900 additions and 94 deletions
@@ -7,18 +7,42 @@
 	objects = {

 /* Begin PBXBuildFile section */
+		5316AF7A188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.h in Headers */ = {isa = PBXBuildFile; fileRef = 5316AF78188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.h */; };
+		5316AF7B188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 5316AF79188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m */; };
+		5316AF95188EFFA100C070DF /* RACSignal+SQRLFileManagerExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 5316AF79188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m */; };
+		5316AFA8188F002100C070DF /* SQRLDownload+Private.h in Headers */ = {isa = PBXBuildFile; fileRef = 5316AFA6188F002100C070DF /* SQRLDownload+Private.h */; };
+		5316AFAC188F0A8E00C070DF /* NSData+SQRLExtensions.h in Headers */ = {isa = PBXBuildFile; fileRef = 5316AFAA188F0A8E00C070DF /* NSData+SQRLExtensions.h */; };
+		5316AFAD188F0A8E00C070DF /* NSData+SQRLExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 5316AFAB188F0A8E00C070DF /* NSData+SQRLExtensions.m */; };
 		533076EB17EB688300BDCCE0 /* IOKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D097B9BC17BB4777006C3FEB /* IOKit.framework */; };
+		53390936184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.h in Headers */ = {isa = PBXBuildFile; fileRef = 53390934184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.h */; };
+		53390937184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.m in Sources */ = {isa = PBXBuildFile; fileRef = 53390935184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.m */; };
+		5339094A184F6322009FA41F /* NSHTTPURLResponseExtensionsSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 53390949184F6322009FA41F /* NSHTTPURLResponseExtensionsSpec.m */; };
 		534FF35B17D8E8B90020A51A /* unused-helper in Copy LoginItems */ = {isa = PBXBuildFile; fileRef = D0B1DDCB17B487D90059C355 /* unused-helper */; };
 		534FF36117D8E90A0020A51A /* Foundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = F60CA7EA179FC4F60069F69A /* Foundation.framework */; };
 		534FF36717D8E90A0020A51A /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = 534FF36517D8E90A0020A51A /* InfoPlist.strings */; };
 		534FF36A17D8E90A0020A51A /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 534FF36917D8E90A0020A51A /* main.m */; };
 		534FF37317D8E9370020A51A /* com.github.Squirrel.TestApplication.TestService.xpc in Copy XPCServices */ = {isa = PBXBuildFile; fileRef = 534FF36017D8E90A0020A51A /* com.github.Squirrel.TestApplication.TestService.xpc */; };
+		53542FC0184F86EC003A6AFD /* Mantle.framework in Copy Frameworks */ = {isa = PBXBuildFile; fileRef = D0A56BA41804B1FD00A84EDC /* Mantle.framework */; };
+		53542FCE184F86F1003A6AFD /* ReactiveCocoa.framework in Copy Frameworks */ = {isa = PBXBuildFile; fileRef = D0F3F05617E83A1D003AFA6B /* ReactiveCocoa.framework */; };
+		53542FCF184F870C003A6AFD /* Mantle.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D0A56BA41804B1FD00A84EDC /* Mantle.framework */; };
+		53542FD2184F8736003A6AFD /* SQRLDownloadedUpdateSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 53542FD1184F8736003A6AFD /* SQRLDownloadedUpdateSpec.m */; };
+		536CD4E2183E5D7F000C0FD1 /* SQRLDownload.h in Headers */ = {isa = PBXBuildFile; fileRef = 536CD4E0183E5D7F000C0FD1 /* SQRLDownload.h */; };
+		536CD4E3183E5D7F000C0FD1 /* SQRLDownload.m in Sources */ = {isa = PBXBuildFile; fileRef = 536CD4E1183E5D7F000C0FD1 /* SQRLDownload.m */; };
 		53710D7417D8F59700A992DE /* SQRLDeepCodesignSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 53710D7317D8F59700A992DE /* SQRLDeepCodesignSpec.m */; };
 		53710D8417D8F5CB00A992DE /* deep-codesign in Resources */ = {isa = PBXBuildFile; fileRef = 53710D7F17D8F5C300A992DE /* deep-codesign */; };
 		5395C0E317E9D013001648E8 /* SQRLUpdateSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 5395C0E217E9D013001648E8 /* SQRLUpdateSpec.m */; };
 		53AACF4B17E9CA0500B41027 /* SQRLUpdate.h in Headers */ = {isa = PBXBuildFile; fileRef = 53AACF4917E9CA0500B41027 /* SQRLUpdate.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		53AACF4C17E9CA0500B41027 /* SQRLUpdate.m in Sources */ = {isa = PBXBuildFile; fileRef = 53AACF4A17E9CA0500B41027 /* SQRLUpdate.m */; };
+		53B0360B184E5C860079FB77 /* SQRLHTTPServer.m in Sources */ = {isa = PBXBuildFile; fileRef = 53B0360A184E5C860079FB77 /* SQRLHTTPServer.m */; };
 		53B70030181E9460000FFBD0 /* OHHTTPStubs.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 53B70025181E944F000FFBD0 /* OHHTTPStubs.framework */; };
+		53C3186F1816C38A0074B481 /* SQRLDownloadManager.h in Headers */ = {isa = PBXBuildFile; fileRef = 53C318691816C38A0074B481 /* SQRLDownloadManager.h */; };
+		53C318701816C38A0074B481 /* SQRLDownloadManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 53C3186A1816C38A0074B481 /* SQRLDownloadManager.m */; };
+		53C318711816C38A0074B481 /* SQRLURLConnection.h in Headers */ = {isa = PBXBuildFile; fileRef = 53C3186B1816C38A0074B481 /* SQRLURLConnection.h */; };
+		53C318721816C38A0074B481 /* SQRLURLConnection.m in Sources */ = {isa = PBXBuildFile; fileRef = 53C3186C1816C38A0074B481 /* SQRLURLConnection.m */; };
+		53C318731816C38A0074B481 /* SQRLResumableDownload.h in Headers */ = {isa = PBXBuildFile; fileRef = 53C3186D1816C38A0074B481 /* SQRLResumableDownload.h */; };
+		53C318741816C38A0074B481 /* SQRLResumableDownload.m in Sources */ = {isa = PBXBuildFile; fileRef = 53C3186E1816C38A0074B481 /* SQRLResumableDownload.m */; };
+		53C3187C1816CCD70074B481 /* SQRLDownloadManagerSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 53C318791816CCD70074B481 /* SQRLDownloadManagerSpec.m */; };
+		53C3187D1816CCD70074B481 /* SQRLURLConnectionSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = 53C3187A1816CCD70074B481 /* SQRLURLConnectionSpec.m */; };
 		D000218F17BACEFF0050109A /* SQRLZipArchiver.m in Sources */ = {isa = PBXBuildFile; fileRef = D000218D17BACEFF0050109A /* SQRLZipArchiver.m */; };
 		D000219717BAD34D0050109A /* TestApplication.app.zip in Resources */ = {isa = PBXBuildFile; fileRef = D000219617BAD34D0050109A /* TestApplication.app.zip */; };
 		D000219917BAD35C0050109A /* SQRLZipArchiverSpec.m in Sources */ = {isa = PBXBuildFile; fileRef = D000219817BAD35C0050109A /* SQRLZipArchiverSpec.m */; };
@@ -387,6 +411,8 @@
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
+				53542FCE184F86F1003A6AFD /* ReactiveCocoa.framework in Copy Frameworks */,
+				53542FC0184F86EC003A6AFD /* Mantle.framework in Copy Frameworks */,
 				D08D4E4917B451F20012B22D /* Squirrel.framework in Copy Frameworks */,
 			);
 			name = "Copy Frameworks";
@@ -406,11 +432,22 @@
 /* End PBXCopyFilesBuildPhase section */

 /* Begin PBXFileReference section */
+		5316AF78188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "RACSignal+SQRLFileManagerExtensions.h"; sourceTree = "<group>"; };
+		5316AF79188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "RACSignal+SQRLFileManagerExtensions.m"; sourceTree = "<group>"; };
+		5316AFA6188F002100C070DF /* SQRLDownload+Private.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "SQRLDownload+Private.h"; sourceTree = "<group>"; };
+		5316AFAA188F0A8E00C070DF /* NSData+SQRLExtensions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSData+SQRLExtensions.h"; sourceTree = "<group>"; };
+		5316AFAB188F0A8E00C070DF /* NSData+SQRLExtensions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSData+SQRLExtensions.m"; sourceTree = "<group>"; };
+		53390934184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSHTTPURLResponse+SQRLExtensions.h"; sourceTree = "<group>"; };
+		53390935184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSHTTPURLResponse+SQRLExtensions.m"; sourceTree = "<group>"; };
+		53390949184F6322009FA41F /* NSHTTPURLResponseExtensionsSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = NSHTTPURLResponseExtensionsSpec.m; sourceTree = "<group>"; };
 		534FF36017D8E90A0020A51A /* com.github.Squirrel.TestApplication.TestService.xpc */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = com.github.Squirrel.TestApplication.TestService.xpc; sourceTree = BUILT_PRODUCTS_DIR; };
 		534FF36417D8E90A0020A51A /* TestService-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "TestService-Info.plist"; sourceTree = "<group>"; };
 		534FF36617D8E90A0020A51A /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = en; path = en.lproj/InfoPlist.strings; sourceTree = "<group>"; };
 		534FF36817D8E90A0020A51A /* TestService-Prefix.pch */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "TestService-Prefix.pch"; sourceTree = "<group>"; };
 		534FF36917D8E90A0020A51A /* main.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = main.m; sourceTree = "<group>"; };
+		53542FD1184F8736003A6AFD /* SQRLDownloadedUpdateSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLDownloadedUpdateSpec.m; sourceTree = "<group>"; };
+		536CD4E0183E5D7F000C0FD1 /* SQRLDownload.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLDownload.h; sourceTree = "<group>"; };
+		536CD4E1183E5D7F000C0FD1 /* SQRLDownload.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLDownload.m; sourceTree = "<group>"; };
 		53710D7317D8F59700A992DE /* SQRLDeepCodesignSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLDeepCodesignSpec.m; sourceTree = "<group>"; };
 		53710D7D17D8F5C300A992DE /* bootstrap */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = bootstrap; sourceTree = "<group>"; };
 		53710D7E17D8F5C300A992DE /* cibuild */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = cibuild; sourceTree = "<group>"; };
@@ -422,6 +459,16 @@
 		5395C0E217E9D013001648E8 /* SQRLUpdateSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLUpdateSpec.m; sourceTree = "<group>"; };
 		53AACF4917E9CA0500B41027 /* SQRLUpdate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLUpdate.h; sourceTree = "<group>"; };
 		53AACF4A17E9CA0500B41027 /* SQRLUpdate.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLUpdate.m; sourceTree = "<group>"; };
+		53B03609184E5C860079FB77 /* SQRLHTTPServer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLHTTPServer.h; sourceTree = "<group>"; };
+		53B0360A184E5C860079FB77 /* SQRLHTTPServer.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLHTTPServer.m; sourceTree = "<group>"; };
+		53C318691816C38A0074B481 /* SQRLDownloadManager.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLDownloadManager.h; sourceTree = "<group>"; };
+		53C3186A1816C38A0074B481 /* SQRLDownloadManager.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLDownloadManager.m; sourceTree = "<group>"; };
+		53C3186B1816C38A0074B481 /* SQRLURLConnection.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLURLConnection.h; sourceTree = "<group>"; };
+		53C3186C1816C38A0074B481 /* SQRLURLConnection.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLURLConnection.m; sourceTree = "<group>"; };
+		53C3186D1816C38A0074B481 /* SQRLResumableDownload.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLResumableDownload.h; sourceTree = "<group>"; };
+		53C3186E1816C38A0074B481 /* SQRLResumableDownload.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLResumableDownload.m; sourceTree = "<group>"; };
+		53C318791816CCD70074B481 /* SQRLDownloadManagerSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLDownloadManagerSpec.m; sourceTree = "<group>"; };
+		53C3187A1816CCD70074B481 /* SQRLURLConnectionSpec.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLURLConnectionSpec.m; sourceTree = "<group>"; };
 		53E1E674181E942300ED813C /* OHHTTPStubs.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = OHHTTPStubs.xcodeproj; path = External/ReactiveCocoa/external/specta/../../../OHHTTPStubs/OHHTTPStubs/OHHTTPStubs.xcodeproj; sourceTree = "<group>"; };
 		D000218C17BACEFF0050109A /* SQRLZipArchiver.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SQRLZipArchiver.h; sourceTree = "<group>"; };
 		D000218D17BACEFF0050109A /* SQRLZipArchiver.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SQRLZipArchiver.m; sourceTree = "<group>"; };
@@ -546,6 +593,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				53542FCF184F870C003A6AFD /* Mantle.framework in Frameworks */,
 				D0F3F06417E83B0B003AFA6B /* ReactiveCocoa.framework in Frameworks */,
 				D08D4E4717B451E50012B22D /* Squirrel.framework in Frameworks */,
 				D08D4E0D17B451500012B22D /* Cocoa.framework in Frameworks */,
@@ -632,11 +680,29 @@
 			name = Products;
 			sourceTree = "<group>";
 		};
+		53C3185A1816C3730074B481 /* Downloads */ = {
+			isa = PBXGroup;
+			children = (
+				53C318691816C38A0074B481 /* SQRLDownloadManager.h */,
+				53C3186A1816C38A0074B481 /* SQRLDownloadManager.m */,
+				536CD4E0183E5D7F000C0FD1 /* SQRLDownload.h */,
+				536CD4E1183E5D7F000C0FD1 /* SQRLDownload.m */,
+				5316AFA6188F002100C070DF /* SQRLDownload+Private.h */,
+				53C3186D1816C38A0074B481 /* SQRLResumableDownload.h */,
+				53C3186E1816C38A0074B481 /* SQRLResumableDownload.m */,
+				53C3186B1816C38A0074B481 /* SQRLURLConnection.h */,
+				53C3186C1816C38A0074B481 /* SQRLURLConnection.m */,
+			);
+			name = Downloads;
+			sourceTree = "<group>";
+		};
 		D00F5B8217E82CFB009A4818 /* Extensions */ = {
 			isa = PBXGroup;
 			children = (
 				D00F5B8917E82D15009A4818 /* NSProcessInfo+SQRLVersionExtensions.h */,
 				D00F5B8A17E82D15009A4818 /* NSProcessInfo+SQRLVersionExtensions.m */,
+				5316AFAA188F0A8E00C070DF /* NSData+SQRLExtensions.h */,
+				5316AFAB188F0A8E00C070DF /* NSData+SQRLExtensions.m */,
 			);
 			name = Extensions;
 			sourceTree = "<group>";
@@ -671,6 +737,10 @@
 				D0964B3B17F2E20B00D88BF7 /* NSBundle+SQRLVersionExtensions.m */,
 				D0EDBE9A17B0C68E0058BC3C /* NSError+SQRLVerbosityExtensions.h */,
 				D0EDBE9B17B0C68E0058BC3C /* NSError+SQRLVerbosityExtensions.m */,
+				53390934184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.h */,
+				53390935184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.m */,
+				5316AF78188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.h */,
+				5316AF79188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m */,
 			);
 			name = Extensions;
 			sourceTree = "<group>";
@@ -693,7 +763,8 @@
 				534FF36217D8E90A0020A51A /* TestService */,
 				D08D4E0F17B451500012B22D /* Supporting Files */,
 			);
-			path = TestApplication;
+			name = TestApplication;
+			path = ../TestApplication;
 			sourceTree = "<group>";
 		};
 		D08D4E0F17B451500012B22D /* Supporting Files */ = {
@@ -780,7 +851,6 @@
 				D0EDBE9F17B0C6930058BC3C /* Shared */,
 				D0C22BE0179CC00E00158214 /* Squirrel */,
 				D0C22BF6179CC00E00158214 /* SquirrelTests */,
-				D08D4E0E17B451500012B22D /* TestApplication */,
 				D014AC0317B97885007D79D0 /* ShipIt */,
 				D0C22BD9179CC00E00158214 /* Frameworks */,
 				53710D7C17D8F5C300A992DE /* Scripts */,
@@ -848,6 +918,7 @@
 		D0C22BF6179CC00E00158214 /* SquirrelTests */ = {
 			isa = PBXGroup;
 			children = (
+				D08D4E0E17B451500012B22D /* TestApplication */,
 				D0C22C4E179CC18000158214 /* Specs */,
 				D0C22BF7179CC00E00158214 /* Supporting Files */,
 			);
@@ -859,6 +930,8 @@
 			children = (
 				D049059E180558B7004E683E /* SQRLTestUpdate.h */,
 				D049059F180558B7004E683E /* SQRLTestUpdate.m */,
+				53B03609184E5C860079FB77 /* SQRLHTTPServer.h */,
+				53B0360A184E5C860079FB77 /* SQRLHTTPServer.m */,
 				D000219617BAD34D0050109A /* TestApplication.app.zip */,
 				D09D244917B59AB30001FAF8 /* TestApplication 2.1.app */,
 				D0C22BF8179CC00E00158214 /* SquirrelTests-Info.plist */,
@@ -936,6 +1009,7 @@
 			isa = PBXGroup;
 			children = (
 				D0964B2817F2DEE700D88BF7 /* Updates */,
+				53C3185A1816C3730074B481 /* Downloads */,
 				D0964B3417F2DEF500D88BF7 /* Archives */,
 				D0964B3517F2DF3100D88BF7 /* IPC */,
 			);
@@ -946,6 +1020,7 @@
 			isa = PBXGroup;
 			children = (
 				D00F5B8D17E82DE6009A4818 /* NSProcessInfoExtensionsSpec.m */,
+				53390949184F6322009FA41F /* NSHTTPURLResponseExtensionsSpec.m */,
 				D0EDBEE017B0E3650058BC3C /* SQRLCodeSignatureVerifierSpec.m */,
 				53710D7317D8F59700A992DE /* SQRLDeepCodesignSpec.m */,
 				D049059A180554BA004E683E /* SQRLDirectoryManagerSpec.m */,
@@ -957,6 +1032,9 @@
 				D0C22C4F179CC18C00158214 /* SQRLUpdaterSpec.m */,
 				5395C0E217E9D013001648E8 /* SQRLUpdateSpec.m */,
 				D000219817BAD35C0050109A /* SQRLZipArchiverSpec.m */,
+				53C318791816CCD70074B481 /* SQRLDownloadManagerSpec.m */,
+				53C3187A1816CCD70074B481 /* SQRLURLConnectionSpec.m */,
+				53542FD1184F8736003A6AFD /* SQRLDownloadedUpdateSpec.m */,
 			);
 			name = Specs;
 			sourceTree = "<group>";
@@ -1016,11 +1094,19 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				53C318711816C38A0074B481 /* SQRLURLConnection.h in Headers */,
 				D0964B3C17F2E20B00D88BF7 /* NSBundle+SQRLVersionExtensions.h in Headers */,
 				D0C22C4C179CC15100158214 /* SQRLUpdater.h in Headers */,
+				5316AFAC188F0A8E00C070DF /* NSData+SQRLExtensions.h in Headers */,
 				D0C22C52179CC23900158214 /* Squirrel.h in Headers */,
+				5316AFA8188F002100C070DF /* SQRLDownload+Private.h in Headers */,
+				53390936184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.h in Headers */,
 				D0964B3817F2E01500D88BF7 /* SQRLDownloadedUpdate.h in Headers */,
 				53AACF4B17E9CA0500B41027 /* SQRLUpdate.h in Headers */,
+				5316AF7A188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.h in Headers */,
+				53C318731816C38A0074B481 /* SQRLResumableDownload.h in Headers */,
+				536CD4E2183E5D7F000C0FD1 /* SQRLDownload.h in Headers */,
+				53C3186F1816C38A0074B481 /* SQRLDownloadManager.h in Headers */,
 				D00F5B8B17E82D15009A4818 /* NSProcessInfo+SQRLVersionExtensions.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -1408,6 +1494,7 @@
 				D014AC1117B9789C007D79D0 /* SQRLInstaller.m in Sources */,
 				D043F77217FF40C90012F996 /* SQRLTerminationListener.m in Sources */,
 				D014AC0517B97885007D79D0 /* ShipIt-main.m in Sources */,
+				5316AF95188EFFA100C070DF /* RACSignal+SQRLFileManagerExtensions.m in Sources */,
 				D014AC1917B979A8007D79D0 /* SQRLCodeSignature.m in Sources */,
 				D06B58B618032B1500656D97 /* RACSignal+SQRLTransactionExtensions.m in Sources */,
 				D014AC1A17B979AA007D79D0 /* NSError+SQRLVerbosityExtensions.m in Sources */,
@@ -1430,18 +1517,25 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				5316AFAD188F0A8E00C070DF /* NSData+SQRLExtensions.m in Sources */,
 				D0964B3D17F2E20B00D88BF7 /* NSBundle+SQRLVersionExtensions.m in Sources */,
 				F6F2ED8417A33C4900F4D220 /* SQRLCodeSignature.m in Sources */,
 				D0D2B6261804E903000EA901 /* SQRLDirectoryManager.m in Sources */,
+				53C318741816C38A0074B481 /* SQRLResumableDownload.m in Sources */,
+				5316AF7B188EFC1800C070DF /* RACSignal+SQRLFileManagerExtensions.m in Sources */,
 				D0964B3917F2E01500D88BF7 /* SQRLDownloadedUpdate.m in Sources */,
 				D014ABB817B96CB3007D79D0 /* SQRLShipItLauncher.m in Sources */,
+				53C318721816C38A0074B481 /* SQRLURLConnection.m in Sources */,
 				D000218F17BACEFF0050109A /* SQRLZipArchiver.m in Sources */,
 				D0C22C4D179CC15100158214 /* SQRLUpdater.m in Sources */,
 				D0EDBE9D17B0C68E0058BC3C /* NSError+SQRLVerbosityExtensions.m in Sources */,
 				53AACF4C17E9CA0500B41027 /* SQRLUpdate.m in Sources */,
 				D0A56BEB1804BA3C00A84EDC /* SQRLShipItState.m in Sources */,
+				53C318701816C38A0074B481 /* SQRLDownloadManager.m in Sources */,
 				D00F5B8C17E82D15009A4818 /* NSProcessInfo+SQRLVersionExtensions.m in Sources */,
+				536CD4E3183E5D7F000C0FD1 /* SQRLDownload.m in Sources */,
 				D06B58B518032B1500656D97 /* RACSignal+SQRLTransactionExtensions.m in Sources */,
+				53390937184F6219009FA41F /* NSHTTPURLResponse+SQRLExtensions.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1451,15 +1545,20 @@
 			files = (
 				5395C0E317E9D013001648E8 /* SQRLUpdateSpec.m in Sources */,
 				D000219917BAD35C0050109A /* SQRLZipArchiverSpec.m in Sources */,
+				53542FD2184F8736003A6AFD /* SQRLDownloadedUpdateSpec.m in Sources */,
 				D043F77E17FF43640012F996 /* SQRLTerminationListener.m in Sources */,
 				D09D244117B595470001FAF8 /* SQRLInstallerSpec.m in Sources */,
 				D0C22C50179CC18C00158214 /* SQRLUpdaterSpec.m in Sources */,
 				D0EDBEDD17B0DB3E0058BC3C /* SQRLTestCase.m in Sources */,
+				5339094A184F6322009FA41F /* NSHTTPURLResponseExtensionsSpec.m in Sources */,
+				53C3187C1816CCD70074B481 /* SQRLDownloadManagerSpec.m in Sources */,
 				D06B58D118035B5A00656D97 /* SQRLTerminationListenerSpec.m in Sources */,
 				D0EDBEE117B0E3650058BC3C /* SQRLCodeSignatureVerifierSpec.m in Sources */,
 				53710D7417D8F59700A992DE /* SQRLDeepCodesignSpec.m in Sources */,
 				D00F5B8E17E82DE6009A4818 /* NSProcessInfoExtensionsSpec.m in Sources */,
+				53B0360B184E5C860079FB77 /* SQRLHTTPServer.m in Sources */,
 				D049059B180554BA004E683E /* SQRLDirectoryManagerSpec.m in Sources */,
+				53C3187D1816CCD70074B481 /* SQRLURLConnectionSpec.m in Sources */,
 				D061E40217FD580D00CC134A /* SQRLInstaller.m in Sources */,
 				D04905A0180558B7004E683E /* SQRLTestUpdate.m in Sources */,
 				D049059D18055671004E683E /* SQRLShipItStateSpec.m in Sources */,
@@ -0,0 +1,19 @@
+//
+//  NSData+SQRLExtensions.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/01/2014.
+//  Copyright (c) 2014 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface NSData (SQRLExtensions)
+
+// Returns an NSData for the SHA1 hash of the receiver.
+- (NSData *)sqrl_SHA1Hash;
+
+// Returns the base16 encoding of the receiver.
+- (NSString *)sqrl_base16String;
+
+@end
@@ -0,0 +1,31 @@
+//
+//  NSData+SQRLExtensions.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/01/2014.
+//  Copyright (c) 2014 GitHub. All rights reserved.
+//
+
+#import "NSData+SQRLExtensions.h"
+
+#import <CommonCrypto/CommonCrypto.h>
+
+@implementation NSData (SQRLExtensions)
+
+- (NSData *)sqrl_SHA1Hash {
+	unsigned char hash[CC_SHA1_DIGEST_LENGTH];
+	CC_SHA1(self.bytes, (CC_LONG)self.length, hash);
+	return [NSData dataWithBytes:hash length:sizeof(hash) / sizeof(*hash)];
+}
+
+- (NSString *)sqrl_base16String {
+	NSMutableString *base16 = [NSMutableString stringWithCapacity:self.length * 2];
+	uint8_t *bytes = (uint8_t *)self.bytes;
+	for (NSUInteger idx = 0; idx < self.length; idx++) {
+		uint8_t byte = *(bytes + idx);
+		[base16 appendFormat:@"%02hhx", byte];
+	}
+	return base16;
+}
+
+@end
@@ -0,0 +1,18 @@
+//
+//  NSHTTPURLResponse+SQRLExtensions.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 04/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface NSHTTPURLResponse (SQRLExtensions)
+
+// Case insensitively look up a header field value.
+//
+// Returns the value of the header if present or nil otherwise.
+- (NSString *)sqrl_valueForHTTPHeaderField:(NSString *)field;
+
+@end
@@ -0,0 +1,26 @@
+//
+//  NSHTTPURLResponse+SQRLExtensions.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 04/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "NSHTTPURLResponse+SQRLExtensions.h"
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+@implementation NSHTTPURLResponse (SQRLExtensions)
+
+- (NSString *)sqrl_valueForHTTPHeaderField:(NSString *)field {
+	return [[[self.allHeaderFields.rac_signal
+		filter:^ BOOL (RACTuple *keyValuePair) {
+			return [keyValuePair[0] caseInsensitiveCompare:field] == NSOrderedSame;
+		}]
+		reduceEach:^(NSString *key, NSString *value) {
+			return value;
+		}]
+		first];
+}
+
+@end
@@ -0,0 +1,15 @@
+//
+//  RACSignal+SQRLFileManagerExtensions.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/01/2014.
+//  Copyright (c) 2014 GitHub. All rights reserved.
+//
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+@interface RACSignal (SQRLFileManagerExtensions)
+
+- (RACSignal *)sqrl_tryCreateDirectory;
+
+@end
@@ -0,0 +1,21 @@
+//
+//  RACSignal+SQRLFileManagerExtensions.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/01/2014.
+//  Copyright (c) 2014 GitHub. All rights reserved.
+//
+
+#import "RACSignal+SQRLFileManagerExtensions.h"
+
+@implementation RACSignal (SQRLFileManagerExtensions)
+
+- (RACSignal *)sqrl_tryCreateDirectory {
+	return [[self
+		try:^(NSURL *directoryURL, NSError **errorRef) {
+			return [NSFileManager.defaultManager createDirectoryAtURL:directoryURL withIntermediateDirectories:YES attributes:nil error:errorRef];
+		}]
+		setNameWithFormat:@"%@ -sqrl_tryCreateDirectory", self];
+}
+
+@end
@@ -26,14 +26,27 @@
 //                 on-disk locations for. This must not be nil.
 - (instancetype)initWithApplicationIdentifier:(NSString *)appIdentifier;

-// Finds or creates an Application Support folder.
+// Finds or creates an Application Support subdirectory for the receiver’s
+// application identifier.
 //
 // Returns a signal which synchronously sends a URL then completes, or errors.
- (RACSignal *)applicationSupportURL;
+@property (readonly, nonatomic) RACSignal *applicationSupportURL;
+
+// Finds or creates a downloads directory to store update downloads in prior to
+// installation. This is an applicationSupportURL subdirectory.
+//
+// Returns a signal which sends a URL then completes, or errors.
+@property (readonly, nonatomic) RACSignal *downloadDirectoryURL;
+
+// Creates a new directory to unpack a downloaded update into prior to
+// installation. This is an applicationSupportURL subdirectory.
+//
+// Returns a signal which sends a URL then completes, or errors.
+- (RACSignal *)createUniqueUpdateDirectoryURL;

 // Determines where archived `SQRLShipItState` should be saved.
 //
 // Returns a signal which synchronously sends a URL then completes, or errors.
- (RACSignal *)shipItStateURL;
+@property (readonly, nonatomic) RACSignal *shipItStateURL;

@end
@@ -8,6 +8,8 @@

 #import "SQRLDirectoryManager.h"
 #import <ReactiveCocoa/ReactiveCocoa.h>
+#import <ReactiveCocoa/EXTScope.h>
+#import "RACSignal+SQRLFileManagerExtensions.h"

@interface SQRLDirectoryManager ()

@@ -53,25 +55,65 @@

 #pragma mark Folder URLs

+ (NSString *)fileSystemNameForIdentifier:(NSString *)identifier {
+	// Periods are problematic in the filesystem because they denote file type.
+	// A directory can become a package which can be undesirable.
+	return [identifier stringByReplacingOccurrencesOfString:@"." withString:@"~"];
+}
+
 - (RACSignal *)applicationSupportURL {
-	return [[RACSignal
+	return [[[[RACSignal
 		defer:^{
 			NSError *error = nil;
-			NSURL *folderURL = [NSFileManager.defaultManager URLForDirectory:NSApplicationSupportDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:&error];
-			if (folderURL == nil) {
+			NSURL *directoryURL = [NSFileManager.defaultManager URLForDirectory:NSApplicationSupportDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:YES error:&error];
+			if (directoryURL == nil) {
 				return [RACSignal error:error];
 			}

-			folderURL = [folderURL URLByAppendingPathComponent:self.applicationIdentifier];
-			if (![NSFileManager.defaultManager createDirectoryAtURL:folderURL withIntermediateDirectories:YES attributes:nil error:&error]) {
-				return [RACSignal error:error];
-			}
-
-			return [RACSignal return:folderURL];
+			return [RACSignal return:directoryURL];
 		}]
+		map:^ (NSURL *directoryURL) {
+			RACSignal *identifierComponents = [@[ self.applicationIdentifier, @"com.github.Squirrel" ].rac_signal
+				map:^(NSString *name) {
+					return [self.class fileSystemNameForIdentifier:name];
+				}];
+
+			RACSignal *pathComponents = [directoryURL.pathComponents.rac_signal concat:identifierComponents];
+			return [NSURL fileURLWithPathComponents:[pathComponents array]];
+		}]
+		sqrl_tryCreateDirectory]
 		setNameWithFormat:@"%@ -applicationSupportURL", self];
 }

+- (RACSignal *)downloadDirectoryURL {
+	return [[[[self
+		applicationSupportURL]
+		map:^(NSURL *directoryURL) {
+			return [directoryURL URLByAppendingPathComponent:@"downloads"];
+		}]
+		sqrl_tryCreateDirectory]
+		setNameWithFormat:@"%@ -downloadDirectoryURL", self];
+}
+
+- (RACSignal *)createUniqueUpdateDirectoryURL {
+	return [[[[self
+		applicationSupportURL]
+		map:^(NSURL *directoryURL) {
+			// noindex so that Spotlight doesn't pick up apps pending update and
+			// add them to the Launch Services database.
+			return [[directoryURL URLByAppendingPathComponent:NSProcessInfo.processInfo.globallyUniqueString] URLByAppendingPathExtension:@"noindex"];
+		}]
+		try:^(NSURL *directoryURL, NSError **errorRef) {
+			// Explicitly just provide the owner with permission, discarding the
+			// current umask. This matches the `mkdtemp` behaviour.
+			NSDictionary *directoryAttributes = @{
+				NSFilePosixPermissions: @(S_IRWXU),
+			};
+			return [NSFileManager.defaultManager createDirectoryAtURL:directoryURL withIntermediateDirectories:YES attributes:directoryAttributes error:errorRef];
+		}]
+		setNameWithFormat:@"%@ -createUniqueUpdateDirectoryURL", self];
+}
+
 - (RACSignal *)shipItStateURL {
 	return [[[self
 		applicationSupportURL]
@@ -0,0 +1,21 @@
+//
+//  SQRLDownload+Private.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/01/2014.
+//  Copyright (c) 2014 GitHub. All rights reserved.
+//
+
+#import "SQRLDownload.h"
+
+@interface SQRLDownload ()
+
+// Designated initialiser.
+//
+// request - Must not be nil. The request this download is for.
+// fileURL - Must not be nil. The file location to save received data to.
+//
+// Returns an initialised download suitable for saving response data.
+- (instancetype)initWithRequest:(NSURLRequest *)request fileURL:(NSURL *)fileURL;
+
+@end
@@ -0,0 +1,31 @@
+//
+//  SQRLDownload.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/11/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Mantle/Mantle.h>
+
+@class RACSignal;
+
+// A download is a file which holds the response body for a request and can be
+// resumed by a subsequent request if the initial transfer is interrupted.
+//
+// Don't create a download directly, instead retrieve one from
+// `SQRLDownloadManager`.
+@interface SQRLDownload : MTLModel
+
+// The `request` the receiver was initialised with.
+@property (readonly, copy, nonatomic) NSURLRequest *request;
+
+// The `fileURL` the receiver was initialised with.
+@property (readonly, copy, nonatomic) NSURL *fileURL;
+
+// Calculate a request suitable for resuming the download.
+//
+// Returns a signal which sends an `NSURLRequest` then completes.
+@property (readonly, nonatomic) RACSignal *resumableRequest;
+
+@end
@@ -0,0 +1,29 @@
+//
+//  SQRLDownload.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 21/11/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLDownload.h"
+#import "SQRLDownload+Private.h"
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+@implementation SQRLDownload
+
+- (instancetype)initWithRequest:(NSURLRequest *)request fileURL:(NSURL *)fileURL {
+	return [self initWithDictionary:@{
+		@keypath(self.request): request,
+		@keypath(self.fileURL): fileURL,
+	} error:NULL];
+}
+
+- (RACSignal *)resumableRequest {
+	return [[RACSignal
+		return:self.request]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+@end
@@ -0,0 +1,61 @@
+//
+//  SQRLDownloadController.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 26/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@class SQRLDownload;
+@class SQRLResumableDownload;
+@class RACSignal;
+@class SQRLDirectoryManager;
+
+// Stores metadata for download resumption, and manages the disk locations for
+// where they're stored.
+@interface SQRLDownloadManager : NSObject
+
+// Default download manager, initializes a download manager with the current
+// application directory manager. Stores downloads in
+// `directoryManager.downloadDirectoryURL`.
+ (instancetype)defaultDownloadManager;
+
+// Designated initialiser.
+//
+// directoryManager - Must not be nil.
+//
+// Returns a download manager which can resume previously started downloads for
+// the initialised directory manager's application.
+- (instancetype)initWithDirectoryManager:(SQRLDirectoryManager *)directoryManager;
+
+// Clean the resumable download state, removes downloaded data and tracking
+// state.
+//
+// Returns a signal which errors or completes when all file operations have been
+// attempted.
+- (RACSignal *)removeAllResumableDownloads;
+
+// Retrieve a previously started download, or initialise a new download.
+//
+// Previously started downloads may have been removed and require
+// reinitialising.
+//
+// request - The request you are performing and require a disk location to save
+//           the response body to. Must not be nil.
+//
+// Returns a signal which sends an `SQRLDownload` object then completes, or
+// errors.
+- (RACSignal *)downloadForRequest:(NSURLRequest *)request;
+
+// Store metadata for a download so that it can be resumed later.
+//
+// download - The download being stored for future resumption. Must not be nil.
+// request  - The request for which the download can be resumed. Must not be
+//            nil.
+//
+// Returns a signal which completes or errors.
+- (RACSignal *)setDownload:(SQRLResumableDownload *)download forRequest:(NSURLRequest *)request;
+
+@end
@@ -0,0 +1,239 @@
+//
+//  SQRLDownloadController.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 26/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLDownloadManager.h"
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+#import "SQRLDirectoryManager.h"
+#import "SQRLDownload.h"
+#import "SQRLDownload+Private.h"
+#import "SQRLResumableDownload.h"
+
+#import "NSData+SQRLExtensions.h"
+
+@interface SQRLDownloadManager ()
+@property (nonatomic, strong, readonly) SQRLDirectoryManager *directoryManager;
+@property (nonatomic, assign, readonly) dispatch_queue_t queue;
+
+// Reads the download index.
+//
+// Returns a signal which sends the download index at time of read then
+// completes, or errors.
+- (RACSignal *)readDownloadIndex;
+
+// Write a new download index.
+//
+// block - Map from the old download index to the new download index. Writing
+//         is serialised, subsequent writers will receive the output of the
+//         previous map block. If the output of the map is equal to the input
+//         no write is attempted and the returned signal completes.
+//
+// Returns a signal which completes or errors.
+- (RACSignal *)writeDownloadIndexWithBlock:(NSDictionary * (^)(NSMutableDictionary *))block;
+@end
+
+@implementation SQRLDownloadManager
+
+ (instancetype)defaultDownloadManager {
+	static SQRLDownloadManager *defaultDownloadManager;
+	static dispatch_once_t defaultDownloadManagerPredicate;
+
+	dispatch_once(&defaultDownloadManagerPredicate, ^{
+		defaultDownloadManager = [[self alloc] initWithDirectoryManager:SQRLDirectoryManager.currentApplicationManager];
+	});
+
+	return defaultDownloadManager;
+}
+
+- (id)initWithDirectoryManager:(SQRLDirectoryManager *)directoryManager {
+	NSParameterAssert(directoryManager != nil);
+
+	self = [super init];
+	if (self == nil) return nil;
+
+	_directoryManager = directoryManager;
+
+	_queue = dispatch_queue_create("com.github.Squirrel.SQRLDownloadManager.queue", DISPATCH_QUEUE_CONCURRENT);
+	dispatch_set_target_queue(_queue, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0));
+
+	return self;
+}
+
+- (void)dealloc {
+	if (_queue != NULL) dispatch_release(_queue);
+}
+
+- (RACSignal *)removeAllResumableDownloads {
+	return [[[RACSignal
+		merge:@[
+			[self downloadStoreIndexFileLocation],
+			[self.directoryManager downloadDirectoryURL]
+		]]
+		flattenMap:^ (NSURL *location) {
+			return [[RACSignal
+				defer:^{
+					NSError *error;
+					BOOL remove = [NSFileManager.defaultManager removeItemAtURL:location error:&error];
+					return (remove ? [RACSignal empty] : [RACSignal error:error]);
+				}]
+				catch:^(NSError *error) {
+					if ([error.domain isEqualToString:NSCocoaErrorDomain] && error.code == NSFileNoSuchFileError) return [RACSignal empty];
+					return [RACSignal error:error];
+				}];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (RACSignal *)downloadStoreIndexFileLocation {
+	return [[[self.directoryManager
+		applicationSupportURL]
+		map:^(NSURL *directory) {
+			return [directory URLByAppendingPathComponent:@"DownloadIndex.plist"];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (RACSignal *)readDownloadIndex {
+	return [[[self
+		downloadStoreIndexFileLocation]
+		flattenMap:^(NSURL *location) {
+			return [RACSignal
+				create:^(id<RACSubscriber> subscriber) {
+					dispatch_async(self.queue, ^{
+						if (subscriber.disposable.disposed) return;
+
+						NSError *error;
+						NSDictionary *propertyList = [self readPropertyListWithContentsOfURL:location error:&error];
+						if (propertyList == nil) {
+							[subscriber sendError:error];
+							return;
+						}
+
+						[subscriber sendNext:propertyList];
+						[subscriber sendCompleted];
+					});
+				}];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (RACSignal *)writeDownloadIndexWithBlock:(NSDictionary * (^)(NSMutableDictionary *))block {
+	NSParameterAssert(block != nil);
+
+	return [[[self
+		downloadStoreIndexFileLocation]
+		flattenMap:^(NSURL *location) {
+			return [RACSignal create:^(id<RACSubscriber> subscriber) {
+				dispatch_barrier_async(self.queue, ^{
+					if (subscriber.disposable.disposed) return;
+
+					NSError *error;
+					NSDictionary *propertyList = [self readPropertyListWithContentsOfURL:location error:&error];
+					if (propertyList == nil) {
+						[subscriber sendError:error];
+						return;
+					}
+
+					NSDictionary *newPropertyList = block([propertyList mutableCopy]);
+					if ([newPropertyList isEqual:propertyList]) {
+						[subscriber sendCompleted];
+						return;
+					}
+
+					NSData *newData = [NSKeyedArchiver archivedDataWithRootObject:newPropertyList];
+					if (newData == nil) {
+						NSDictionary *errorInfo = @{ NSURLErrorKey: location };
+						[subscriber sendError:[NSError errorWithDomain:NSCocoaErrorDomain code:NSPropertyListWriteStreamError userInfo:errorInfo]];
+						return;
+					}
+
+					BOOL write = [newData writeToURL:location options:NSDataWritingAtomic error:&error];
+					if (!write) {
+						[subscriber sendError:error];
+						return;
+					}
+
+					[subscriber sendCompleted];
+				});
+			}];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (NSDictionary *)readPropertyListWithContentsOfURL:(NSURL *)location error:(NSError **)errorRef {
+	NSData *propertyListData = [NSData dataWithContentsOfURL:location options:NSDataReadingUncached error:NULL];
+	if (propertyListData == nil) {
+		return @{};
+	}
+
+	NSDictionary *propertyList = [NSKeyedUnarchiver unarchiveObjectWithData:propertyListData];
+	if (propertyList == nil) {
+		if (errorRef != NULL) {
+			NSDictionary *errorInfo = @{ NSURLErrorKey: location };
+			*errorRef = [NSError errorWithDomain:NSCocoaErrorDomain code:NSPropertyListReadCorruptError userInfo:errorInfo];
+		}
+		return nil;
+	}
+
+	return propertyList;
+}
+
+ (NSString *)keyForURL:(NSURL *)URL {
+	return URL.absoluteString;
+}
+
+ (NSString *)fileNameForURL:(NSURL *)URL {
+	NSString *key = [self keyForURL:URL];
+	return [[[key dataUsingEncoding:NSUTF8StringEncoding] sqrl_SHA1Hash] sqrl_base16String];
+}
+
+- (RACSignal *)downloadForRequest:(NSURLRequest *)request {
+	NSParameterAssert(request != nil);
+
+	return [[[[self
+		readDownloadIndex]
+		map:^(NSDictionary *index) {
+			NSString *key = [self.class keyForURL:request.URL];
+			return index[key];
+		}]
+		flattenMap:^(SQRLResumableDownload *download) {
+			if (download != nil) return [RACSignal return:download];
+
+			return [[[self.directoryManager
+				downloadDirectoryURL]
+				map:^(NSURL *downloadDirectory) {
+					return [downloadDirectory URLByAppendingPathComponent:[self.class fileNameForURL:request.URL]];
+				}]
+				map:^(NSURL *location) {
+					return [[SQRLDownload alloc] initWithRequest:request fileURL:location];
+				}];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (RACSignal *)setDownload:(SQRLResumableDownload *)download forRequest:(NSURLRequest *)request {
+	NSParameterAssert(download.response != nil);
+	NSParameterAssert(request != nil);
+
+	return [[self
+		writeDownloadIndexWithBlock:^(NSMutableDictionary *index) {
+			NSString *key = [self.class keyForURL:request.URL];
+
+			if (download != nil) {
+				index[key] = download;
+			} else {
+				[index removeObjectForKey:key];
+			}
+
+			return index;
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+@end
@@ -11,7 +11,7 @@
@class SQRLUpdate;

 // A SQRLUpdate that has been successfully downloaded to disk.
-@interface SQRLDownloadedUpdate : MTLModel
+@interface SQRLDownloadedUpdate : MTLModel <MTLJSONSerializing>

 // The application bundle representing the downloaded and unarchived update.
@property (nonatomic, strong, readonly) NSBundle *bundle;
@@ -7,6 +7,7 @@
 //

 #import "SQRLDownloadedUpdate.h"
+#import "SQRLUpdate.h"
 #import <ReactiveCocoa/ReactiveCocoa.h>

@interface SQRLDownloadedUpdate ()
@@ -40,9 +41,15 @@
 #pragma mark MTLJSONSerializing

 + (NSDictionary *)JSONKeyPathsByPropertyKey {
-	return [super.JSONKeyPathsByPropertyKey mtl_dictionaryByAddingEntriesFromDictionary:@{
-		@keypath(SQRLDownloadedUpdate.new, bundleURL): NSNull.null
-	}];
+	return @{};
+}
+
+ (NSValueTransformer *)updateJSONTransformer {
+	return [MTLValueTransformer mtl_JSONDictionaryTransformerWithModelClass:SQRLUpdate.class];
+}
+
+ (NSValueTransformer *)bundleURLJSONTransformer {
+	return [NSValueTransformer valueTransformerForName:MTLURLValueTransformerName];
 }

@end
@@ -0,0 +1,27 @@
+//
+//  SQRLResumableDownload.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 30/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+#import "SQRLDownload.h"
+
+// A download which has already been started and already has partial data.
+@interface SQRLResumableDownload : SQRLDownload
+
+// Designated initialiser.
+//
+// request  - See `SQRLDownload`.
+// response - HTTP response whose body is being downloaded to `fileURL`.
+//            Must not be nil.
+// fileURL  - See `SQRLDownload`.
+- (instancetype)initWithRequest:(NSURLRequest *)request response:(NSHTTPURLResponse *)response fileURL:(NSURL *)fileURL;
+
+// The `response` the receiver was initialised with.
+@property (readonly, copy, nonatomic) NSHTTPURLResponse *response;
+
+@end
@@ -0,0 +1,66 @@
+//
+//  SQRLResumableDownload.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 30/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLResumableDownload.h"
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+#import "NSHTTPURLResponse+SQRLExtensions.h"
+
+@implementation SQRLResumableDownload
+
+- (instancetype)initWithRequest:(NSURLRequest *)request response:(NSHTTPURLResponse *)response fileURL:(NSURL *)fileURL {
+	NSParameterAssert(request != nil);
+	NSParameterAssert(response != nil);
+	NSParameterAssert(fileURL != nil);
+
+	return [self initWithDictionary:@{
+		@keypath(self.request): request,
+		@keypath(self.response): response,
+		@keypath(self.fileURL): fileURL,
+	} error:NULL];
+}
+
+- (BOOL)isEqual:(SQRLResumableDownload *)object {
+	if (self == object) return YES;
+	if (![object isKindOfClass:self.class]) return NO;
+
+	if (!(self.response == nil && object.response == nil) && ![self responseEqual:object.response]) return NO;
+	if (![object.fileURL isEqual:self.fileURL]) return NO;
+
+	return YES;
+}
+
+- (BOOL)responseEqual:(NSHTTPURLResponse *)response {
+	if (![response.URL isEqual:self.response.URL]) return NO;
+	if (response.statusCode != self.response.statusCode) return NO;
+	if (![response.allHeaderFields isEqual:self.response.allHeaderFields]) return NO;
+	return YES;
+}
+
+- (RACSignal *)resumableRequest {
+	return [[[super
+		resumableRequest]
+		map:^ NSURLRequest * (NSURLRequest *request) {
+			NSHTTPURLResponse *response = self.response;
+			NSString *ETag = [response sqrl_valueForHTTPHeaderField:@"ETag"];
+			if (ETag == nil) return request;
+
+			NSNumber *alreadyDownloadedSize = nil;
+			BOOL getAlreadyDownloadedSize = [self.fileURL getResourceValue:&alreadyDownloadedSize forKey:NSURLFileSizeKey error:NULL];
+			if (!getAlreadyDownloadedSize) return request;
+
+			NSMutableURLRequest *newRequest = [request mutableCopy];
+			[newRequest setValue:ETag forHTTPHeaderField:@"If-Range"];
+			[newRequest setValue:[NSString stringWithFormat:@"%llu-", alreadyDownloadedSize.unsignedLongLongValue] forHTTPHeaderField:@"Range"];
+			return newRequest;
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+@end
@@ -0,0 +1,49 @@
+//
+//  SQRLURLConnection.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 25/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@class SQRLDownloadManager;
+@class RACSignal;
+
+// Resumably download a remote resource.
+//
+// If the resource has previously been downloaded this operation may return the
+// URL of an existing file, contingent on the server matching the ETag of the
+// original response.
+@interface SQRLURLConnection : NSObject
+
+// This is the designated initialiser. The body of the response is streamed to
+// disk. If the response includes an ETag the download can be resumed
+// automatically by subsequent download operations initialised with a request of
+// equal URL.
+//
+// request - Must not be nil, the request is issued with NSURLConnection.
+- (instancetype)initWithRequest:(NSURLRequest *)request __attribute__((nonnull (1)));
+
+// Starts accumulating the resource body in memory, cancels when the
+// subscription is disposed.
+//
+// Returns a signal when sends a tuple of `NSURLResponse` and `NSData`, then
+// completes or errors.
+- (RACSignal *)retrieve;
+
+// Starts downloading the resource body to disk, resuming from a previous
+// download if possible, cancels when the subscription is disposed.
+//
+// downloadManager - Must be non nil, determines where the downloads will be
+//                   stored and resumed from. For a previously started download
+//                   to be resumed, an equivalent download manager should be
+//                   provided.
+//
+// Returns a signal which sends a tuple of `NSURLResponse` and a file
+// scheme `NSURL` where the resource has been stored on disk, then completes, or
+// errors.
+- (RACSignal *)download:(SQRLDownloadManager *)downloadManager __attribute__((nonnull (1)));
+
+@end
@@ -0,0 +1,257 @@
+//
+//  SQRLURLConnection.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 25/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLURLConnection.h"
+
+#import <ReactiveCocoa/ReactiveCocoa.h>
+#import <ReactiveCocoa/EXTScope.h>
+
+#import "SQRLDownloadManager.h"
+#import "SQRLResumableDownload.h"
+
+@interface SQRLURLConnection ()
+// The request the downloader was initialised with.
+@property (nonatomic, copy, readonly) NSURLRequest *request;
+
+// Listens for invocations of `selector` on the receiver.
+//
+// The first argument of `selector` must be an `NSURLConnection` object.
+//
+// Returns a signal which sends the _second_ argument of `selector`, or
+// RACUnit if there is only one argument, then completes when the receiver
+// deallocates.
+- (RACSignal *)signalForDelegateSelector:(SEL)selector;
+
+// Subscribes to the connection delegate selectors and starts a connection for
+// `request`.
+//
+// request - The request to perform, must not be nil.
+// mapData - For each response, map the data received for that response to a
+//           result.
+//
+// Returns a signal which sends a tuple of the last response, and the first
+// value from the last `mapData`, then completes, or errors.
+- (RACSignal *)connectionSignalWithRequest:(NSURLRequest *)request mapData:(RACSignal * (^)(NSURLResponse *, RACSignal *))mapData;
+
+@end
+
+@implementation SQRLURLConnection
+
+- (instancetype)initWithRequest:(NSURLRequest *)request {
+	NSParameterAssert(request != nil);
+
+	self = [self init];
+	if (self == nil) return nil;
+
+	_request = [request copy];
+
+	return self;
+}
+
+- (RACSignal *)signalForDelegateSelector:(SEL)selector {
+	NSParameterAssert(selector != NULL);
+
+	return [[self
+		rac_signalForSelector:selector]
+		map:^(RACTuple *args) {
+			return args[1] ?: RACUnit.defaultUnit;
+		}];
+}
+
+- (RACSignal *)connectionSignalWithRequest:(NSURLRequest *)request mapData:(RACSignal * (^)(NSURLResponse *, RACSignal *))mapData {
+	return [[RACSignal
+		create:^(id<RACSubscriber> subscriber) {
+			// A signal that will error if the connection fails for any reason.
+			RACSignal *errors = [[self
+				signalForDelegateSelector:@selector(connection:didFailWithError:)]
+				flattenMap:^(NSError *error) {
+					return [RACSignal error:error];
+				}];
+
+			// Sends (or replays) RACUnit when the connection has finished
+			// loading successfully.
+			RACSignal *finished = [[[[self
+				signalForDelegateSelector:@selector(connectionDidFinishLoading:)]
+				take:1]
+				promiseOnScheduler:RACScheduler.immediateScheduler]
+				start];
+
+			// A signal of all `NSURLResponse`s received on the connection.
+			RACSignal *responses = [[self
+				signalForDelegateSelector:@selector(connection:didReceiveResponse:)]
+				takeUntil:finished];
+
+			// A signal of all `NSData` received on the connection.
+			RACSignal *data = [[self
+				signalForDelegateSelector:@selector(connection:didReceiveData:)]
+				takeUntil:finished];
+
+			[[[[[RACSignal
+				merge:@[ responses, errors ]]
+				takeUntil:finished]
+				map:^(NSURLResponse *response) {
+					return [RACSignal
+						zip:@[
+							[RACSignal return:response],
+							mapData(response, data),
+						]];
+				}]
+				switchToLatest]
+				subscribe:subscriber];
+
+			NSOperationQueue *delegateQueue = [[NSOperationQueue alloc] init];
+			delegateQueue.maxConcurrentOperationCount = 1;
+
+			NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
+			connection.delegateQueue = delegateQueue;
+
+			[connection start];
+
+			[subscriber.disposable addDisposable:[RACDisposable disposableWithBlock:^{
+				[connection cancel];
+			}]];
+		}]
+		setNameWithFormat:@"%@ %s %@", self, sel_getName(_cmd), request];
+}
+
+#pragma mark Download
+
+- (RACSignal *)truncateDownload:(SQRLDownload *)download {
+	NSParameterAssert(download != nil);
+
+	return [[[[RACSignal
+		defer:^{
+			NSError *error = nil;
+			BOOL remove = [NSFileManager.defaultManager removeItemAtURL:download.fileURL error:&error];
+			return (remove ? [RACSignal empty] : [RACSignal error:error]);
+		}]
+		catch:^(NSError *error) {
+			if ([error.domain isEqualToString:NSCocoaErrorDomain] && error.code == NSFileNoSuchFileError) return [RACSignal empty];
+			return [RACSignal error:error];
+		}]
+		concat:[RACSignal return:download]]
+		setNameWithFormat:@"%@ %s %@", self, sel_getName(_cmd), download];
+}
+
+- (RACSignal *)recordDownload:(SQRLResumableDownload *)download downloadManager:(SQRLDownloadManager *)downloadManager {
+	NSParameterAssert(download != nil);
+	NSParameterAssert(downloadManager != nil);
+
+	return [[[downloadManager
+		setDownload:download forRequest:self.request]
+		concat:[RACSignal return:download]]
+		setNameWithFormat:@"%@ %s %@", self, sel_getName(_cmd), download];
+}
+
+- (RACSignal *)prepareDownload:(SQRLDownload *)download downloadManager:(SQRLDownloadManager *)downloadManager forResponse:(NSURLResponse *)response {
+	return [[RACSignal
+		defer:^{
+			if (![response isKindOfClass:NSHTTPURLResponse.class]) {
+				return [self truncateDownload:download];
+			}
+
+			NSHTTPURLResponse *httpResponse = (id)response;
+
+			RACSignal *downloadSignal;
+			if (httpResponse.statusCode != 206 /* Partial Data */) {
+				downloadSignal = [self truncateDownload:download];
+			} else {
+				downloadSignal = [RACSignal empty];
+			}
+
+			SQRLResumableDownload *newDownload = [[SQRLResumableDownload alloc] initWithRequest:self.request response:httpResponse fileURL:download.fileURL];
+
+			return [[downloadSignal
+				ignoreValues]
+				concat:[self recordDownload:newDownload downloadManager:downloadManager]];
+		}]
+		setNameWithFormat:@"%@ %s %@", self, sel_getName(_cmd), response];
+}
+
+- (BOOL)appendData:(NSData *)data toURL:(NSURL *)fileURL error:(NSError **)errorRef {
+	NSOutputStream *outputStream = [NSOutputStream outputStreamWithURL:fileURL append:YES];
+
+	[outputStream open];
+	@onExit {
+		[outputStream close];
+	};
+
+	uint8_t const *bytes = data.bytes;
+	size_t length = data.length;
+	while (length > 0) {
+		NSInteger written = [outputStream write:bytes maxLength:length];
+		if (written == -1) {
+			NSError *streamError = outputStream.streamError;
+			if ([streamError.domain isEqualToString:NSPOSIXErrorDomain] && streamError.code == EINTR) continue;
+
+			if (errorRef != NULL) *errorRef = streamError;
+			return NO;
+		}
+		
+		bytes += written;
+		length -= written;
+	}
+
+	return YES;
+}
+
+#pragma mark Start
+
+- (RACSignal *)retrieve {
+	return [[self
+		connectionSignalWithRequest:self.request mapData:^(id _, RACSignal *data) {
+			return [data
+				aggregateWithStart:[NSMutableData data] reduce:^(NSMutableData *running, NSData *data) {
+					[running appendData:data];
+					return running;
+				}];
+		}]
+		setNameWithFormat:@"%@ %s", self, sel_getName(_cmd)];
+}
+
+- (RACSignal *)download:(SQRLDownloadManager *)downloadManager {
+	NSParameterAssert(downloadManager != nil);
+
+	RACSignal *download = [[[downloadManager
+		downloadForRequest:self.request]
+		promiseOnScheduler:RACScheduler.immediateScheduler]
+		deferred];
+
+	return [[[download
+		flattenMap:^(SQRLDownload *download) {
+			return [download resumableRequest];
+		}]
+		flattenMap:^(NSURLRequest *request) {
+			return [self connectionSignalWithRequest:request mapData:^(NSURLResponse *response, RACSignal *data) {
+				RACSignal *downloadURL = [[[[download
+					flattenMap:^(SQRLDownload *download) {
+						return [self prepareDownload:download downloadManager:downloadManager forResponse:response];
+					}]
+					map:^(SQRLDownload *download) {
+						return download.fileURL;
+					}]
+					promiseOnScheduler:RACScheduler.immediateScheduler]
+					deferred];
+
+				return [[[[data
+					map:^(NSData *bodyData) {
+						return [[downloadURL
+							try:^(NSURL *fileURL, NSError **errorRef) {
+								return [self appendData:bodyData toURL:fileURL error:errorRef];
+							}]
+							ignoreValues];
+					}]
+					concat]
+					ignoreValues]
+					concat:downloadURL];
+			}];
+		}]
+		setNameWithFormat:@"%@ download: %@", self, downloadManager];
+}
+
+@end
@@ -14,6 +14,8 @@ NSString * const SQRLUpdateJSONReleaseNotesKey = @"notes";
 NSString * const SQRLUpdateJSONNameKey = @"name";
 NSString * const SQRLUpdateJSONPublicationDateKey = @"pub_date";

+NSString * const SQRLUpdateErrorDomain = @"SQRLUpdateErrorDomain";
+
@implementation SQRLUpdate

 #pragma mark Lifecycle
@@ -50,7 +52,7 @@ NSString * const SQRLUpdateJSONPublicationDateKey = @"pub_date";

 			*error = [NSError errorWithDomain:NSCocoaErrorDomain code:NSKeyValueValidationError userInfo:userInfo];
 		}
-		
+
 		return NO;
 	}

@@ -61,10 +63,10 @@ NSString * const SQRLUpdateJSONPublicationDateKey = @"pub_date";

 + (NSDictionary *)JSONKeyPathsByPropertyKey {
 	return @{
-		@keypath(SQRLUpdate.new, releaseNotes): @"notes",
-		@keypath(SQRLUpdate.new, releaseName): @"name",
-		@keypath(SQRLUpdate.new, releaseDate): @"pub_date",
-		@keypath(SQRLUpdate.new, updateURL): @"url",
+		@keypath(SQRLUpdate.new, releaseNotes): SQRLUpdateJSONReleaseNotesKey,
+		@keypath(SQRLUpdate.new, releaseName): SQRLUpdateJSONNameKey,
+		@keypath(SQRLUpdate.new, releaseDate): SQRLUpdateJSONPublicationDateKey,
+		@keypath(SQRLUpdate.new, updateURL): SQRLUpdateJSONURLKey,
 	};
 }

@@ -94,8 +96,8 @@ NSString * const SQRLUpdateJSONPublicationDateKey = @"pub_date";
 		}

 		// If neither match, try removing the ':' in the time zone
-		static NSRegularExpression *timeZoneSuffix = nil;
-		static dispatch_once_t timeZoneSuffixPredicate = 0;
+		static NSRegularExpression *timeZoneSuffix;
+		static dispatch_once_t timeZoneSuffixPredicate;
 		dispatch_once(&timeZoneSuffixPredicate, ^ {
 			timeZoneSuffix = [NSRegularExpression regularExpressionWithPattern:@"([-+])([0-9]{2}):([0-9]{2})$" options:0 error:NULL];
 		});
@@ -142,7 +144,7 @@ NSString * const SQRLUpdateJSONPublicationDateKey = @"pub_date";
 			};
 			*error = [NSError errorWithDomain:NSCocoaErrorDomain code:NSKeyValueValidationError userInfo:userInfo];
 		}
-		
+
 		return NO;
 	}

@@ -17,9 +17,13 @@
 #import "SQRLShipItLauncher.h"
 #import "SQRLShipItState.h"
 #import "SQRLUpdate.h"
+#import "SQRLDownloadedUpdate.h"
 #import "SQRLZipArchiver.h"
 #import <ReactiveCocoa/EXTScope.h>
 #import <ReactiveCocoa/ReactiveCocoa.h>
+#import "SQRLURLConnection.h"
+#import "SQRLURLConnection.h"
+#import "SQRLDownloadManager.h"

 NSString * const SQRLUpdaterErrorDomain = @"SQRLUpdaterErrorDomain";
 NSString * const SQRLUpdaterServerDataErrorKey = @"SQRLUpdaterServerDataErrorKey";
@@ -34,6 +38,9 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;

@interface SQRLUpdater ()

+// The directory manager used for downloads and unpacks.
+@property (nonatomic, strong, readonly) SQRLDirectoryManager *directoryManager;
+
 // The code signature for the running application, used to check updates before
 // sending them to ShipIt.
@property (nonatomic, strong, readonly) SQRLCodeSignature *signature;
@@ -62,22 +69,25 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 // errors, on a background thread.
 - (RACSignal *)downloadAndPrepareUpdate:(SQRLUpdate *)update;

-// Downloads the archived bundle associated with the given update.
+// Downloads the update archive for the given update.
 //
 // update            - Describes the update to install. This must not be nil.
-// downloadDirectory - A directory in which to create a temporary directory for this
-//                     download. This must not be nil.
+// downloadDirectory - A directory in which to create a temporary directory for
+//                     this download. This must not be nil.
 //
-// Returns a signal which sends an unarchived `NSBundle` then completes, or
-// errors, on a background thread.
- (RACSignal *)downloadBundleForUpdate:(SQRLUpdate *)update intoDirectory:(NSURL *)downloadDirectory;
+// Returns a signal which sends an NSURL of the downloaded update archive then
+// completes, or errors, on a background thread.
+- (RACSignal *)downloadArchiveForUpdate:(SQRLUpdate *)update intoDirectory:(NSURL *)downloadDirectory;

-// Creates a unique directory in which to save the update bundle, for later use
-// by ShipIt.
+// Unpacks an update archive.
 //
-// Returns a signal which sends an `NSURL` then completes, or errors, on an
-// unspecified thread.
- (RACSignal *)uniqueTemporaryDirectoryForUpdate;
+// archiveURL   - The location of the update archive, currently only ZIP
+//                archives are supported. Must not be nil.
+// directoryURL - A directory in which to place the unpacked contents of the
+//                archive. Must not be nil.
+//
+// Returns a signal which completes or errors.
+- (RACSignal *)unpackArchiveAtURL:(NSURL *)archiveURL intoDirectory:(NSURL *)directoryURL;

 // Recursively searches the given directory for an application bundle that has
 // the same identifier as the running application.
@@ -149,6 +159,8 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 	_updateRequest = [updateRequest copy];
 	_updateClass = SQRLUpdate.class;

+	_directoryManager = SQRLDirectoryManager.currentApplicationManager;
+
 	NSError *error = nil;
 	_signature = [SQRLCodeSignature currentApplicationSignature:&error];
 	NSAssert(_signature != nil, @"Could not get code signature for running application: %@", error);
@@ -157,10 +169,10 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 	_checkForUpdatesAction = [[[RACSignal
 		defer:^{
 			@strongify(self);
-
 			return [RACSignal return:self.updateRequest];
 		}]
 		flattenMap:^(NSURLRequest *request) {
+			@strongify(self);
 			return [self checkForUpdates:request];
 		}]
 		action];
@@ -184,7 +196,7 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 		promiseOnScheduler:RACScheduler.immediateScheduler]
 		deferred]
 		setNameWithFormat:@"shipItLauncher"];
-	
+
 	return self;
 }

@@ -296,14 +308,21 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 		setNameWithFormat:@"%@ -updateFromJSONData:", self];
 }

+#pragma Download
+
 - (RACSignal *)downloadAndPrepareUpdate:(SQRLUpdate *)update {
 	NSParameterAssert(update != nil);

-	return [[[self
-		uniqueTemporaryDirectoryForUpdate]
+	return [[[self.directoryManager
+		createUniqueUpdateDirectoryURL]
 		flattenMap:^(NSURL *downloadDirectory) {
-			return [[[self
-				downloadBundleForUpdate:update intoDirectory:downloadDirectory]
+			return [[[[[[self
+				downloadArchiveForUpdate:update intoDirectory:downloadDirectory]
+				flattenMap:^(NSURL *updateArchiveURL) {
+					return [self unpackArchiveAtURL:updateArchiveURL intoDirectory:downloadDirectory];
+				}]
+				ignoreValues]
+				concat:[self updateBundleMatchingCurrentApplicationInDirectory:downloadDirectory]]
 				flattenMap:^(NSBundle *updateBundle) {
 					return [self verifyAndPrepareUpdate:update fromBundle:updateBundle];
 				}]
@@ -317,86 +336,65 @@ const NSInteger SQRLUpdaterErrorInvalidServerBody = 7;
 		setNameWithFormat:@"%@ -downloadAndPrepareUpdate: %@", self, update];
 }

- (RACSignal *)downloadBundleForUpdate:(SQRLUpdate *)update intoDirectory:(NSURL *)downloadDirectory {
+- (RACSignal *)downloadArchiveForUpdate:(SQRLUpdate *)update intoDirectory:(NSURL *)downloadDirectory {
 	NSParameterAssert(update != nil);
 	NSParameterAssert(downloadDirectory != nil);

-	return [[[[[RACSignal
+	return [[[RACSignal
 		defer:^{
 			NSURL *zipDownloadURL = update.updateURL;
 			NSMutableURLRequest *zipDownloadRequest = [NSMutableURLRequest requestWithURL:zipDownloadURL];
 			[zipDownloadRequest setValue:@"application/zip" forHTTPHeaderField:@"Accept"];

-			return [[[[NSURLConnection
-				rac_sendAsynchronousRequest:zipDownloadRequest]
-				reduceEach:^(NSURLResponse *response, NSData *bodyData) {
+			SQRLURLConnection *connection = [[SQRLURLConnection alloc] initWithRequest:zipDownloadRequest];
+
+			SQRLDownloadManager *downloadManager = [[SQRLDownloadManager alloc] initWithDirectoryManager:self.directoryManager];
+
+			return [[[[connection
+				download:downloadManager]
+				reduceEach:^(NSURLResponse *response, NSURL *bodyLocation) {
 					if ([response isKindOfClass:NSHTTPURLResponse.class]) {
 						NSHTTPURLResponse *httpResponse = (id)response;
 						if (!(httpResponse.statusCode >= 200 && httpResponse.statusCode <= 299)) {
 							NSDictionary *errorInfo = @{
 								NSLocalizedDescriptionKey: NSLocalizedString(@"Update download failed", nil),
 								NSLocalizedRecoverySuggestionErrorKey: NSLocalizedString(@"The server sent an invalid response. Try again later.", nil),
-								SQRLUpdaterServerDataErrorKey: bodyData,
 							};
 							NSError *error = [NSError errorWithDomain:SQRLUpdaterErrorDomain code:SQRLUpdaterErrorInvalidServerResponse userInfo:errorInfo];
 							return [RACSignal error:error];
 						}
 					}

-					return [RACSignal return:bodyData];
+					return [[RACSignal
+						return:bodyLocation]
+						tryMap:^ NSURL * (NSURL *bodyLocation, NSError **errorRef) {
+							NSURL *updateLocation = [downloadDirectory URLByAppendingPathComponent:response.suggestedFilename];
+							if (![NSFileManager.defaultManager moveItemAtURL:bodyLocation toURL:updateLocation error:errorRef]) return nil;
+							return updateLocation;
+						}];
 				}]
 				flatten]
-				flattenMap:^(NSData *data) {
-					NSURL *zipOutputURL = [downloadDirectory URLByAppendingPathComponent:zipDownloadURL.lastPathComponent];
-
-					NSError *error = nil; 
-					if ([data writeToURL:zipOutputURL options:NSDataWritingAtomic error:&error]) {
-						return [RACSignal return:zipOutputURL];
-					} else {
-						return [RACSignal error:error];
-					}
-				}];
+				concat:[[downloadManager
+					removeAllResumableDownloads]
+					catchTo:RACSignal.empty]];
 		}]
 		doNext:^(NSURL *zipOutputURL) {
 			NSLog(@"Download completed to: %@", zipOutputURL);
 		}]
-		flattenMap:^(NSURL *zipOutputURL) {
-			return [SQRLZipArchiver unzipArchiveAtURL:zipOutputURL intoDirectoryAtURL:downloadDirectory];
-		}]
-		concat:[self updateBundleMatchingCurrentApplicationInDirectory:downloadDirectory]]
-		setNameWithFormat:@"%@ -downloadBundleForUpdate: %@ intoDirectory: %@", self, update, downloadDirectory];
+		setNameWithFormat:@"%@ -downloadArchiveForUpdate: %@ intoDirectory: %@", self, update, downloadDirectory];
 }

 #pragma mark File Management

- (RACSignal *)uniqueTemporaryDirectoryForUpdate {
-	return [[[RACSignal
+- (RACSignal *)unpackArchiveAtURL:(NSURL *)archiveURL intoDirectory:(NSURL *)directoryURL {
+	NSParameterAssert(archiveURL != nil);
+	NSParameterAssert(directoryURL != nil);
+
+	return [[RACSignal
 		defer:^{
-			SQRLDirectoryManager *directoryManager = [[SQRLDirectoryManager alloc] initWithApplicationIdentifier:SQRLShipItLauncher.shipItJobLabel];
-			return [directoryManager applicationSupportURL];
+			return [SQRLZipArchiver unzipArchiveAtURL:archiveURL intoDirectoryAtURL:directoryURL];
 		}]
-		flattenMap:^(NSURL *appSupportURL) {
-			NSURL *updateDirectoryTemplate = [appSupportURL URLByAppendingPathComponent:@"update.XXXXXXX"];
-			char *updateDirectoryCString = strdup(updateDirectoryTemplate.path.fileSystemRepresentation);
-			@onExit {
-				free(updateDirectoryCString);
-			};
-			
-			if (mkdtemp(updateDirectoryCString) == NULL) {
-				int code = errno;
-
-				NSDictionary *userInfo = @{
-					NSLocalizedDescriptionKey: NSLocalizedString(@"Could not create temporary directory", nil),
-					NSURLErrorKey: updateDirectoryTemplate
-				};
-
-				return [RACSignal error:[NSError errorWithDomain:NSPOSIXErrorDomain code:code userInfo:userInfo]];
-			}
-
-			NSString *updateDirectoryPath = [NSFileManager.defaultManager stringWithFileSystemRepresentation:updateDirectoryCString length:strlen(updateDirectoryCString)];
-			return [RACSignal return:[NSURL fileURLWithPath:updateDirectoryPath isDirectory:YES]];
-		}]
-		setNameWithFormat:@"%@ -uniqueTemporaryDirectoryForUpdate", self];
+		setNameWithFormat:@"%@ unpackArchiveAtURL: %@ intoDirectory: %@", self, archiveURL, directoryURL];
 }

 - (RACSignal *)updateBundleMatchingCurrentApplicationInDirectory:(NSURL *)directory {
@@ -0,0 +1,23 @@
+//
+//  NSHTTPURLResponseExtensionsSpec.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 04/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "NSHTTPURLResponse+SQRLExtensions.h"
+
+SpecBegin(NSHTTPURLResponseExtensions)
+
+it(@"should perform case insensitive key look up", ^{
+	NSDictionary *headers = @{
+		@"ETag": @"foo",
+	};
+	NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:[NSURL URLWithString:@"http://localhost"] statusCode:200 HTTPVersion:(__bridge NSString *)kCFHTTPVersion1_1 headerFields:headers];
+
+	expect([response sqrl_valueForHTTPHeaderField:@"etag"]).to.equal(@"foo");
+	expect([response sqrl_valueForHTTPHeaderField:@"ETAG"]).to.equal(@"foo");
+});
+
+SpecEnd
@@ -0,0 +1,87 @@
+//
+//  SQRLDownloadControllerSpec.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 27/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLDownloadManager.h"
+#import "SQRLResumableDownload.h"
+#import "NSError+SQRLVerbosityExtensions.h"
+#import <ReactiveCocoa/ReactiveCocoa.h>
+
+SpecBegin(SQRLDownloadManager)
+
+__block SQRLDownloadManager *downloadManager = nil;
+
+beforeAll(^{
+	downloadManager = SQRLDownloadManager.defaultDownloadManager;
+
+	NSError *removeError = nil;
+	BOOL remove = [[downloadManager removeAllResumableDownloads] waitUntilCompleted:&removeError];
+	if (!remove) {
+		if ([removeError.domain isEqualToString:NSCocoaErrorDomain] && removeError.code == NSFileNoSuchFileError) return;
+		
+		NSLog(@"Couldn’t remove resumable downloads %@", removeError.sqrl_verboseDescription);
+	}
+});
+
+NSURL * (^newTestURL)() = ^ () {
+	return [[NSURL alloc] initWithScheme:@"http" host:@"localhost" path:[@"/" stringByAppendingString:NSProcessInfo.processInfo.globallyUniqueString]];
+};
+
+NSURL * (^newDownloadURL)() = ^ () {
+	NSError *error = nil;
+	SQRLResumableDownload *download = [[downloadManager downloadForRequest:[NSURLRequest requestWithURL:newTestURL()]] firstOrDefault:nil success:NULL error:&error];
+	expect(download).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSURL *downloadURL = download.fileURL;
+	expect(downloadURL).notTo.beNil();
+
+	return downloadURL;
+};
+
+it(@"should return a file that doesn't exist yet for new URLs", ^{
+	NSURL *downloadURL = newDownloadURL();
+
+	BOOL exists = [NSFileManager.defaultManager fileExistsAtPath:downloadURL.path];
+	expect(exists).to.beFalsy();
+});
+
+it(@"should return a path in a writable directory for new URLs", ^{
+	NSURL *downloadURL = newDownloadURL();
+
+	BOOL writable = [NSFileManager.defaultManager isWritableFileAtPath:downloadURL.URLByDeletingLastPathComponent.path];
+	expect(writable).to.beTruthy();
+});
+
+it(@"should return the same path for the same URL", ^{
+	NSURL *testURL = newTestURL();
+
+	SQRLDownload *download1 = [[downloadManager downloadForRequest:[NSURLRequest requestWithURL:testURL]] first];
+	SQRLDownload *download2 = [[downloadManager downloadForRequest:[NSURLRequest requestWithURL:testURL]] first];
+	expect(download1).notTo.beNil();
+	expect(download1).to.equal(download2);
+});
+
+it(@"should remember a response", ^{
+	NSURLRequest *request = [NSURLRequest requestWithURL:newTestURL()];
+	NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:request.URL statusCode:200 HTTPVersion:(__bridge NSString *)kCFHTTPVersion1_1 headerFields:@{ @"ETag": NSProcessInfo.processInfo.globallyUniqueString }];
+
+	SQRLDownload *initialDownload = [[downloadManager downloadForRequest:request] first];
+
+	SQRLResumableDownload *newDownload = [[SQRLResumableDownload alloc] initWithRequest:request response:response fileURL:initialDownload.fileURL];
+	expect(newDownload).notTo.equal(initialDownload);
+
+	NSError *error = nil;
+	BOOL setNewDownload = [[downloadManager setDownload:newDownload forRequest:request] waitUntilCompleted:&error];
+	expect(setNewDownload).to.beTruthy();
+	expect(error).to.beNil();
+
+	SQRLResumableDownload *resumedDownload = [[downloadManager downloadForRequest:request] first];
+	expect(newDownload).to.equal(resumedDownload);
+});
+
+SpecEnd
@@ -0,0 +1,40 @@
+//
+//  SQRLDownloadedUpdateSpec.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 04/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+SpecBegin(SQRLDownloadedUpdate)
+
+it(@"should serialise to JSON", ^{
+	NSError *error = nil;
+	SQRLUpdate *update = [SQRLUpdate modelWithDictionary:@{
+		@keypath(SQRLUpdate.new, updateURL) : [NSURL URLWithString:@"http://fake.domain/path"],
+	} error:&error];
+	expect(update).notTo.beNil();
+
+	NSURL *testApplicationURL = [self createTestApplicationUpdate];
+	NSBundle *testApplicationBundle = [NSBundle bundleWithURL:testApplicationURL];
+	expect(testApplicationBundle).notTo.beNil();
+
+	SQRLDownloadedUpdate *downloadedUpdate = [[SQRLDownloadedUpdate alloc] initWithUpdate:update bundle:testApplicationBundle];
+	expect(downloadedUpdate).notTo.beNil();
+
+	NSDictionary *JSONDictionary = [MTLJSONAdapter JSONDictionaryFromModel:downloadedUpdate];
+	expect(JSONDictionary).notTo.beNil();
+
+	NSData *JSONData = [NSJSONSerialization dataWithJSONObject:JSONDictionary options:0 error:&error];
+	expect(JSONData).notTo.beNil();
+	expect(error).to.beNil();
+
+	JSONDictionary = [NSJSONSerialization JSONObjectWithData:JSONData options:0 error:&error];
+	expect(JSONDictionary).notTo.beNil();
+
+	SQRLDownloadedUpdate *downloadedUpdate2 = [MTLJSONAdapter modelOfClass:SQRLDownloadedUpdate.class fromJSONDictionary:JSONDictionary error:&error];
+	expect(downloadedUpdate2).to.equal(downloadedUpdate);
+	expect(error).to.beNil();
+});
+
+SpecEnd
@@ -0,0 +1,18 @@
+//
+//  SQRLHTTPServer.h
+//  Squirrel
+//
+//  Created by Keith Duncan on 03/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface SQRLHTTPServer : NSObject
+
+- (NSURL *)start:(NSError **)errorRef;
+- (void)invalidate;
+
+@property (copy, nonatomic) CFHTTPMessageRef (^responseBlock)(CFHTTPMessageRef request);
+
+@end
@@ -0,0 +1,165 @@
+//
+//  SQRLHTTPServer.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 03/12/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLHTTPServer.h"
+
+#import <sys/socket.h>
+#import <netinet/in.h>
+
+@interface SQRLHTTPServer ()
+@property (assign, nonatomic) dispatch_source_t listenerSource;
+@property (strong, nonatomic) NSMutableArray *cleanupBlocks;
+@end
+
+@implementation SQRLHTTPServer
+
+- (id)init {
+	self = [super init];
+	if (self == nil) return nil;
+
+	_cleanupBlocks = [[NSMutableArray alloc] init];
+
+	return self;
+}
+
+- (void)dealloc {
+	[self invalidate];
+}
+
+- (NSURL *)start:(NSError **)errorRef {
+	NSParameterAssert(self.listenerSource == NULL);
+
+	int listenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+	struct sockaddr_in listenAddress = {
+		.sin_len = sizeof(listenAddress),
+		.sin_family = AF_INET,
+		.sin_port = 0,
+		.sin_addr = {
+			.s_addr = htonl(INADDR_LOOPBACK),
+		},
+	};
+	int bindError = bind(listenSocket, (struct sockaddr const *)&listenAddress, listenAddress.sin_len);
+	if (bindError != 0) {
+		close(listenSocket);
+
+		if (errorRef != NULL) *errorRef = [NSError errorWithDomain:NSPOSIXErrorDomain code:bindError userInfo:nil];
+		return nil;
+	}
+
+	listen(listenSocket, 128);
+
+	dispatch_source_t source = dispatch_source_create(DISPATCH_SOURCE_TYPE_READ, listenSocket, 0, NULL);
+	dispatch_source_set_event_handler(source, ^{
+		int connectionSocket = accept(listenSocket, NULL, NULL);
+		// Wait to close the connection until after the test case is complete.
+		// We need NSURLConnection to timeout, closing the connection causes it
+		// to error immediately.
+		[self addCleanupBlock:^{
+			close(connectionSocket);
+		}];
+
+		CFHTTPMessageRef request = (__bridge CFHTTPMessageRef)CFBridgingRelease(CFHTTPMessageCreateEmpty(kCFAllocatorDefault, true));
+
+		while (1) {
+			uint8_t buffer;
+			ssize_t readLength = read(connectionSocket, &buffer, 1);
+			if (readLength < 0) {
+				return;
+			}
+
+			CFHTTPMessageAppendBytes(request, (UInt8 const *)&buffer, readLength);
+			if (!CFHTTPMessageIsHeaderComplete(request)) {
+				continue;
+			}
+
+			// Doesn't support reading requests with a body for simplicity
+			NSString *contentLength = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("Content-Length")));
+			if (contentLength != nil) {
+				return;
+			}
+
+			break;
+		}
+
+		NSLog(@"Received Request:");
+		NSLog(@"%@", [[NSString alloc] initWithData:CFBridgingRelease(CFHTTPMessageCopySerializedMessage(request)) encoding:NSASCIIStringEncoding]);
+
+		CFHTTPMessageRef response = self.responseBlock(request);
+		NSData *responseData = CFBridgingRelease(CFHTTPMessageCopySerializedMessage(response));
+
+		NSLog(@"Sending Response:");
+		NSLog(@"%@", [[NSString alloc] initWithData:responseData encoding:NSASCIIStringEncoding]);
+
+		size_t bufferLength = responseData.length;
+		uint8_t const *buffer = responseData.bytes;
+
+		while (1) {
+			ssize_t writeLength = write(connectionSocket, buffer, bufferLength);
+			if (writeLength < 0) {
+				return;
+			}
+
+			buffer += writeLength;
+			bufferLength -= writeLength;
+
+			if (bufferLength == 0) {
+				break;
+			}
+		}
+	});
+	dispatch_source_set_cancel_handler(source, ^{
+		close(listenSocket);
+	});
+	dispatch_resume(source);
+
+	struct sockaddr_storage localAddress = {};
+	socklen_t localAddressLength = sizeof(localAddress);
+	int localAddressError = getsockname(listenSocket, (struct sockaddr *)&localAddress, &localAddressLength);
+	if (localAddressError != 0) {
+		dispatch_release(source);
+
+		if (errorRef != NULL) *errorRef = [NSError errorWithDomain:NSPOSIXErrorDomain code:localAddressError userInfo:nil];
+		return nil;
+	}
+
+	self.listenerSource = source;
+
+	// IPv4 and IPv6 address transport layer port fields are at the same offset
+	// and are the same size
+	in_port_t port = ntohs(((struct sockaddr_in *)&localAddress)->sin_port);
+
+	return [NSURL URLWithString:[NSString stringWithFormat:@"http://localhost:%ld/", (unsigned long)port]];
+}
+
+- (void)invalidate {
+	dispatch_source_t listenerSource = self.listenerSource;
+	if (listenerSource == NULL) return;
+
+	dispatch_source_cancel(listenerSource);
+	dispatch_release(listenerSource);
+
+	self.listenerSource = NULL;
+
+	[self performCleanup];
+}
+
+- (void)addCleanupBlock:(void (^)(void))block {
+	[self.cleanupBlocks addObject:[block copy]];
+}
+
+- (void)performCleanup {
+	NSArray *blocks = [self.cleanupBlocks copy];
+	[self.cleanupBlocks removeAllObjects];
+
+	for (void (^currentBlock)(void) in blocks) {
+		currentBlock();
+	}
+}
+
+@end
@@ -0,0 +1,311 @@
+//
+//  SQRLURLConnectionSpec.m
+//  Squirrel
+//
+//  Created by Keith Duncan on 27/09/2013.
+//  Copyright (c) 2013 GitHub. All rights reserved.
+//
+
+#import "SQRLURLConnection.h"
+#import "SQRLDownloadManager.h"
+#import "SQRLResumableDownload.h"
+#import <ReactiveCocoa/EXTScope.h>
+#import "NSError+SQRLVerbosityExtensions.h"
+#import "SQRLHTTPServer.h"
+
+SpecBegin(SQRLURLConnection);
+
+__block SQRLDownloadManager *downloadManager;
+
+beforeAll(^{
+	downloadManager = SQRLDownloadManager.defaultDownloadManager;
+
+	NSError *removeError = nil;
+	BOOL remove = [[downloadManager
+		removeAllResumableDownloads]
+		waitUntilCompleted:&removeError];
+	expect(remove).to.beTruthy();
+	expect(removeError).to.beNil();
+});
+
+beforeEach(^{
+	Expecta.asynchronousTestTimeout = 60.;
+});
+
+afterAll(^{
+	Expecta.asynchronousTestTimeout = 1.;
+});
+
+describe(@"file scheme URLs", ^{
+	NSURL *fileLocation = [self.temporaryDirectoryURL URLByAppendingPathComponent:@"test"];
+	NSData *testContents = [@"test" dataUsingEncoding:NSUTF8StringEncoding];
+
+	NSError *error;
+	BOOL write = [testContents writeToURL:fileLocation options:0 error:&error];
+	expect(write).to.beTruthy();
+	expect(error).to.beNil();
+
+	NSURLRequest *request = [NSURLRequest requestWithURL:fileLocation];
+
+	__block SQRLURLConnection *connection;
+
+	beforeEach(^{
+		connection = [[SQRLURLConnection alloc] initWithRequest:request];
+	});
+
+	void (^testBodyEqualTestContents)(NSData *) = ^ (NSData *body) {
+		expect(body.length).to.equal(testContents.length);
+		expect(body).to.equal(testContents);
+	};
+
+	it(@"should retrieve file:// scheme URLs", ^{
+		NSError *error;
+		RACTuple *result = [[connection retrieve] firstOrDefault:nil success:NULL error:&error];
+		expect(result).notTo.beNil();
+		expect(error).to.beNil();
+
+		testBodyEqualTestContents(result[1]);
+	});
+
+	it(@"should download file:// scheme URLs", ^{
+		NSError *error;
+		RACTuple *result = [[connection download:downloadManager] firstOrDefault:nil success:NULL error:&error];
+		expect(result).notTo.beNil();
+		expect(error).to.beNil();
+
+		NSURL *location = result[1];
+
+		NSData *body = [NSData dataWithContentsOfURL:location options:0 error:&error];
+		expect(error).to.beNil();
+		testBodyEqualTestContents(body);
+	});
+});
+
+static NSData * (^stringTimes)(NSString *, NSUInteger) = ^ (NSString *string, NSUInteger times) {
+	NSData *stringData = [string dataUsingEncoding:NSUTF8StringEncoding];
+	NSMutableData *data = [NSMutableData dataWithCapacity:(stringData.length + 2) * times];
+	for (NSUInteger idx = 0; idx < times; idx++) {
+		[data appendData:stringData];
+		[data appendData:[NSData dataWithBytes:"\r\n" length:2]];
+	}
+	return data;
+};
+
+static SQRLHTTPServer * (^newHttpServer)(SQRLTestCase *) = ^ (SQRLTestCase *self) {
+	SQRLHTTPServer *server = [[SQRLHTTPServer alloc] init];
+
+	[self addCleanupBlock:^{
+		[server invalidate];
+	}];
+
+	return server;
+};
+
+it(@"should resume a download", ^{
+	// Start server
+
+	SQRLHTTPServer *server = newHttpServer(self);
+
+	NSError *error = nil;
+	NSURL *baseURL = [server start:&error];
+	expect(baseURL).notTo.beNil();
+	expect(error).to.beNil();
+
+	error = nil;
+
+
+	// Prepare half response
+
+	NSData *firstHalf = stringTimes(@"the quick brown fox", 100);
+	NSData *secondHalf = stringTimes(@"jumped over the lazy doge", 100);
+
+	NSString *ETag = NSProcessInfo.processInfo.globallyUniqueString;
+
+	CFHTTPMessageRef serverResponse = (__bridge CFHTTPMessageRef)CFBridgingRelease(CFHTTPMessageCreateResponse(kCFAllocatorDefault, 200, NULL, kCFHTTPVersion1_1));
+	NSDictionary *responseHeaders = @{
+		@"Content-Length": [@(firstHalf.length + secondHalf.length) stringValue],
+		@"ETag": ETag,
+	};
+	[responseHeaders enumerateKeysAndObjectsUsingBlock:^(NSString *key, NSString *obj, BOOL *stop) {
+		CFHTTPMessageSetHeaderFieldValue(serverResponse, (__bridge CFStringRef)key, (__bridge CFStringRef)obj);
+	}];
+	CFHTTPMessageSetBody(serverResponse, (__bridge CFDataRef)firstHalf);
+
+	server.responseBlock = ^ (CFHTTPMessageRef request) {
+		NSString *ifRange = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("If-Range")));
+		expect(ifRange).to.beNil();
+
+		NSString *range = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("Range")));
+		expect(range).to.beNil();
+
+		return serverResponse;
+	};
+
+
+	// Issue first request
+
+	NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:baseURL];
+	request.timeoutInterval = 1.;
+	SQRLURLConnection *connection = [[SQRLURLConnection alloc] initWithRequest:request];
+	RACTuple *result = [[connection download:downloadManager] firstOrDefault:nil success:NULL error:&error];
+	expect(result).to.beNil();
+	expect(error).notTo.beNil();
+
+	error = nil;
+
+	SQRLResumableDownload *download = [[downloadManager downloadForRequest:request] firstOrDefault:nil success:NULL error:&error];
+	expect(download).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSData *downloadedData = [NSData dataWithContentsOfURL:download.fileURL options:0 error:&error];
+	expect(downloadedData.length).to.equal(firstHalf.length);
+	expect(downloadedData).to.equal(firstHalf);
+	expect(error).to.beNil();
+
+
+	// Prepare remainder response
+
+	serverResponse = CFHTTPMessageCreateResponse(kCFAllocatorDefault, 206, NULL, kCFHTTPVersion1_1);
+	responseHeaders = @{
+		@"Content-Length": [@(secondHalf.length) stringValue],
+		@"Range": [NSString stringWithFormat:@"%lu-%lu", firstHalf.length, secondHalf.length - 1],
+		@"ETag": ETag,
+	};
+	[responseHeaders enumerateKeysAndObjectsUsingBlock:^(NSString *key, NSString *obj, BOOL *stop) {
+		CFHTTPMessageSetHeaderFieldValue(serverResponse, (__bridge CFStringRef)key, (__bridge CFStringRef)obj);
+	}];
+	CFHTTPMessageSetBody(serverResponse, (__bridge CFDataRef)secondHalf);
+
+	server.responseBlock = ^ (CFHTTPMessageRef request) {
+		NSString *ifRange = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("If-Range")));
+		expect(ifRange).to.equal(ETag);
+
+		NSString *range = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("Range")));
+		expect(range).to.equal(([NSString stringWithFormat:@"%lu-", firstHalf.length]));
+
+		return serverResponse;
+	};
+
+
+	// Issue second request
+
+	connection = [[SQRLURLConnection alloc] initWithRequest:request];
+	result = [[connection download:downloadManager] firstOrDefault:nil success:NULL error:&error];
+	expect(result).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSURL *location = result[1];
+
+	NSMutableData *fullBody = [firstHalf mutableCopy];
+	[fullBody appendData:secondHalf];
+
+	downloadedData = [NSData dataWithContentsOfURL:location options:0 error:&error];
+	expect(downloadedData.length).to.equal(fullBody.length);
+	expect(downloadedData).to.equal(fullBody);
+	expect(error).to.beNil();
+});
+
+it(@"should not resume downloads for a response with a different ETag", ^{
+	// Start server
+
+	SQRLHTTPServer *server = newHttpServer(self);
+
+	NSError *error = nil;
+	NSURL *baseURL = [server start:&error];
+	expect(baseURL).notTo.beNil();
+	expect(error).to.beNil();
+
+	error = nil;
+
+
+	// Prepare first response
+
+	NSData *firstBody = stringTimes(@"the quick brown fox", 100);
+	NSString *firstETag = NSProcessInfo.processInfo.globallyUniqueString;
+
+	CFHTTPMessageRef serverResponse = (__bridge CFHTTPMessageRef)CFBridgingRelease(CFHTTPMessageCreateResponse(kCFAllocatorDefault, 200, NULL, kCFHTTPVersion1_1));
+	NSDictionary *responseHeaders = @{
+		// Claim the response to be longer so that the connection will timeout
+		// waiting for the extra bytes
+		@"Content-Length": [@(firstBody.length + 100) stringValue],
+		@"ETag": firstETag,
+	};
+	[responseHeaders enumerateKeysAndObjectsUsingBlock:^(NSString *key, NSString *obj, BOOL *stop) {
+		CFHTTPMessageSetHeaderFieldValue(serverResponse, (__bridge CFStringRef)key, (__bridge CFStringRef)obj);
+	}];
+	CFHTTPMessageSetBody(serverResponse, (__bridge CFDataRef)firstBody);
+
+	server.responseBlock = ^ (CFHTTPMessageRef request) {
+		NSString *ifRange = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("If-Range")));
+		expect(ifRange).to.beNil();
+
+		NSString *range = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("Range")));
+		expect(range).to.beNil();
+
+		return serverResponse;
+	};
+
+
+	// Issue first request
+
+	NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:baseURL];
+	request.timeoutInterval = 1.;
+	SQRLURLConnection *connection = [[SQRLURLConnection alloc] initWithRequest:request];
+	RACTuple *result = [[connection download:downloadManager] firstOrDefault:nil success:NULL error:&error];
+	expect(result).to.beNil();
+	expect(error).notTo.beNil();
+
+	error = nil;
+
+	SQRLResumableDownload *download = [[downloadManager downloadForRequest:request] firstOrDefault:nil success:NULL error:&error];
+	expect(download).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSData *downloadedData = [NSData dataWithContentsOfURL:download.fileURL options:0 error:&error];
+	expect(downloadedData.length).to.equal(firstBody.length);
+	expect(downloadedData).to.equal(firstBody);
+	expect(error).to.beNil();
+
+
+	// Prepare second response
+
+	NSData *secondBody = stringTimes(@"jumps over the lazy doge", 100);
+	NSString *secondETag = NSProcessInfo.processInfo.globallyUniqueString;
+
+	serverResponse = (__bridge CFHTTPMessageRef)CFBridgingRelease(CFHTTPMessageCreateResponse(kCFAllocatorDefault, 200, NULL, kCFHTTPVersion1_1));
+	responseHeaders = @{
+		@"Content-Length": [@(secondBody.length) stringValue],
+		@"ETag": secondETag,
+	};
+	[responseHeaders enumerateKeysAndObjectsUsingBlock:^(NSString *key, NSString *obj, BOOL *stop) {
+		CFHTTPMessageSetHeaderFieldValue(serverResponse, (__bridge CFStringRef)key, (__bridge CFStringRef)obj);
+	}];
+	CFHTTPMessageSetBody(serverResponse, (__bridge CFDataRef)secondBody);
+
+	server.responseBlock = ^ (CFHTTPMessageRef request) {
+		NSString *ifRange = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("If-Range")));
+		expect(ifRange).to.equal(firstETag);
+
+		NSString *range = CFBridgingRelease(CFHTTPMessageCopyHeaderFieldValue(request, CFSTR("Range")));
+		expect(range).to.equal(([NSString stringWithFormat:@"%lu-", firstBody.length]));
+
+		return serverResponse;
+	};
+
+
+	// Issue second request
+
+	connection = [[SQRLURLConnection alloc] initWithRequest:request];
+	result = [[connection download:downloadManager] firstOrDefault:nil success:NULL error:&error];
+	expect(result).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSURL *location = result[1];
+
+	downloadedData = [NSData dataWithContentsOfURL:location options:0 error:&error];
+	expect(downloadedData.length).to.equal(secondBody.length);
+	expect(downloadedData).to.equal(secondBody);
+	expect(error).to.beNil();
+});
+
+SpecEnd
@@ -39,13 +39,17 @@ it(@"should validate release name and notes", ^{
 });

 it(@"should parse Central style dates", ^{
-	SQRLUpdate *update = [MTLJSONAdapter modelOfClass:SQRLUpdate.class fromJSONDictionary:@{ @"url": @"http://example.com/update", @"pub_date": @"Tue Sep 17 10:24:27 -0700 2013" } error:NULL];
+	NSError *error = nil;
+	SQRLUpdate *update = [MTLJSONAdapter modelOfClass:SQRLUpdate.class fromJSONDictionary:@{ @"url": @"http://example.com/update", @"pub_date": @"Tue Sep 17 10:24:27 -0700 2013" } error:&error];
 	expect(update.releaseDate).notTo.beNil();
+	expect(error).to.beNil();
 });

 it(@"should parse ISO 8601 dates", ^{
-	SQRLUpdate *update = [MTLJSONAdapter modelOfClass:SQRLUpdate.class fromJSONDictionary:@{ @"url": @"http://example.com/update", @"pub_date": @"2013-09-18T13:17:07+01:00" } error:NULL];
+	NSError *error = nil;
+	SQRLUpdate *update = [MTLJSONAdapter modelOfClass:SQRLUpdate.class fromJSONDictionary:@{ @"url": @"http://example.com/update", @"pub_date": @"2013-09-18T13:17:07+01:00" } error:&error];
 	expect(update.releaseDate).notTo.beNil();
+	expect(error).to.beNil();
 });

 SpecEnd
@@ -9,6 +9,9 @@
 #import "SQRLTestUpdate.h"
 #import "SQRLZipArchiver.h"
 #import "OHHTTPStubs/OHHTTPStubs.h"
+#import "SQRLDirectoryManager.h"
+#import "SQRLURLConnection.h"
+#import "SQRLDownloadManager.h"

 SpecBegin(SQRLUpdater)

@@ -179,4 +182,83 @@ describe(@"response handling", ^{
 	});
 });

+it(@"should clean up resumable downloads after a successful download", ^{
+	SQRLDirectoryManager *directoryManager = [[SQRLDirectoryManager alloc] initWithApplicationIdentifier:@"com.github.Squirrel.TestApplication"];
+	SQRLDownloadManager *downloadManager = [[SQRLDownloadManager alloc] initWithDirectoryManager:directoryManager];
+
+	NSError *error = nil;
+	BOOL remove = [[downloadManager removeAllResumableDownloads] asynchronouslyWaitUntilCompleted:&error];
+	expect(remove).to.beTruthy();
+	expect(error).to.beNil();
+
+	NSURL *updateApplicationBundle = [self createTestApplicationUpdate];
+
+	NSURL *firstDownload = zipUpdate(updateApplicationBundle);
+	SQRLURLConnection *connection = [[SQRLURLConnection alloc] initWithRequest:[NSURLRequest requestWithURL:firstDownload]];
+	BOOL download = [[connection download:downloadManager] asynchronouslyWaitUntilCompleted:&error];
+	expect(download).to.beTruthy();
+	expect(error).to.beNil();
+
+	NSURL *downloadDirectory = [[directoryManager downloadDirectoryURL] firstOrDefault:nil success:NULL error:&error];
+	expect(downloadDirectory).notTo.beNil();
+	expect(error).to.beNil();
+
+	NSArray *contents = [NSFileManager.defaultManager contentsOfDirectoryAtURL:downloadDirectory includingPropertiesForKeys:@[] options:0 error:&error];
+	expect(contents.count).to.equal(1);
+
+	SQRLTestUpdate *update = [[SQRLTestUpdate alloc] initWithDictionary:@{
+		@"updateURL": zipUpdate(updateApplicationBundle),
+		@"final": @YES,
+	} error:NULL];
+
+	writeUpdate(update);
+
+	NSRunningApplication *app = launchWithEnvironment(nil);
+	expect(app.terminated).will.beTruthy();
+	expect(self.testApplicationBundleVersion).will.equal(SQRLTestApplicationUpdatedShortVersionString);
+
+	contents = [NSFileManager.defaultManager contentsOfDirectoryAtURL:downloadDirectory includingPropertiesForKeys:@[] options:0 error:&error];
+	if (contents == nil) {
+		expect(error.domain).to.equal(NSCocoaErrorDomain);
+		expect(error.code).to.equal(NSFileReadNoSuchFileError);
+	} else {
+		expect(contents.count).to.equal(0);
+	}
+});
+
+it(@"should unpack update archives into a .noindex directory", ^{
+	NSURL *zippedUpdateLocation = zipUpdate([self createTestApplicationUpdate]);
+
+	SQRLTestUpdate *update = [[SQRLTestUpdate alloc] initWithDictionary:@{
+		@keypath(update.updateURL): zippedUpdateLocation,
+	} error:NULL];
+
+	writeUpdate(update);
+
+	__block SQRLDownloadedUpdate *downloadedUpdate;
+
+	[[[[[NSDistributedNotificationCenter.defaultCenter
+		rac_addObserverForName:@"com.github.Squirrel.TestApplication.updateReceived" object:nil]
+		map:^(NSNotification *notification) {
+			return notification.userInfo[@"update"];
+		}]
+		tryMap:^(NSString *serialisedUpdate, NSError **errorRef) {
+			NSData *JSONData = [serialisedUpdate dataUsingEncoding:NSUTF8StringEncoding];
+			return [NSJSONSerialization JSONObjectWithData:JSONData options:0 error:errorRef];
+		}]
+		tryMap:^(NSDictionary *JSONDictionary, NSError **errorRef) {
+			return [MTLJSONAdapter modelOfClass:SQRLDownloadedUpdate.class fromJSONDictionary:JSONDictionary error:errorRef];
+		}]
+		subscribeNext:^(SQRLDownloadedUpdate *update) {
+			downloadedUpdate = update;
+		}];
+
+	launchWithEnvironment(nil);
+
+	expect(downloadedUpdate).willNot.beNil();
+
+	NSURL *bundleURL = downloadedUpdate.bundle.bundleURL;
+	expect([bundleURL.path rangeOfString:@".noindex"].location).notTo.equal(NSNotFound);
+});
+
 SpecEnd
@@ -9,7 +9,7 @@
 #import "SQRLCodeSignature.h"
 #import "SQRLZipArchiver.h"

-SpecBegin(SQRLZipArchiver)
+SpecBegin(SQRLZipOperation)

 it(@"should extract a zip archive created by the Finder", ^{
 	NSURL *zipURL = [[NSBundle bundleForClass:self.class] URLForResource:@"TestApplication.app" withExtension:@"zip"];
@@ -10,6 +10,7 @@
 #import "SQRLDirectoryManager.h"
 #import "SQRLShipItLauncher.h"
 #import "SQRLTestUpdate.h"
+#import "SQRLDownloadedUpdate.h"
 #import <ReactiveCocoa/EXTScope.h>
 #import <ReactiveCocoa/ReactiveCocoa.h>

@@ -74,6 +75,10 @@
 		}]
 		doNext:^(SQRLDownloadedUpdate *update) {
 			NSLog(@"Got a candidate update: %@", update);
+
+			NSString *serialisedUpdate = [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:[MTLJSONAdapter JSONDictionaryFromModel:update] options:0 error:NULL] encoding:NSUTF8StringEncoding];
+
+			[NSDistributedNotificationCenter.defaultCenter postNotificationName:@"com.github.Squirrel.TestApplication.updateReceived" object:nil userInfo:@{ @"update": serialisedUpdate }];
 		}]
 		// Retry until we get the expected release.
 		repeat]