Merge pull request #2104 from barijaona/RSS-button

Use FeedDiscoverer to enable browser's RSS button
This adds the discovery of JSON Feeds to BrowserTab.

Vienna/Sources/Main window/BrowserTab+RSSSource.swift

@@ -21,10 +21,7 @@ import Foundation
 
 extension BrowserTab: RSSSource {
 
-    static let extractRssLinkScript = """
-        Array.from( document.querySelectorAll("link[type*='rss'], link[type*='atom']"),
-            function(link) {return new URL(link.getAttribute('href'), document.baseURI).href;} );
-    """
+    static let extractHTMLSource = "document.documentElement.outerHTML"
 
     var rssUrls: [URL] {
         get {
@@ -80,13 +77,13 @@ extension BrowserTab: RSSSource {
         // use javascript to detect RSS feed link
         // TODO: deal with multiple links
         waitForAsyncExecution(until: DispatchTime.now() + DispatchTimeInterval.milliseconds(200)) { [weak self] finishHandler in
-            self?.webView.evaluateJavaScript(BrowserTab.extractRssLinkScript) { result, error in
+            self?.webView.evaluateJavaScript(BrowserTab.extractHTMLSource) { result, error in
                 defer { finishHandler() }
-                if let result = result as? [String], error == nil {
-                    // RSS feed link(s) detected
-                    self?.rssUrls = result.compactMap { URL(string: $0 as String) }
+                if let html = result as? String, let data = html.data(using: .utf8), let baseUrl = self?.url, error == nil {
+                    let discoverer = FeedDiscoverer(data: data, baseURL: baseUrl)
+                    self?.rssUrls = discoverer.feedURLs().map(\.absoluteURL)
                 } else {
-                    // error or no rss url available
+                    // error or conversion problem
                     self?.rssUrls = []
                 }
             }