JSONEncoder/JSONDecoder and String convenience methods (#144)

Co-authored-by: Konrad `ktoso` Malawski <konrad.malawski@project13.pl>

Sources/AWSLambdaRuntime/Lambda+Codable.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 @_exported import AWSLambdaRuntimeCore
+import struct Foundation.Data
 import class Foundation.JSONDecoder
 import class Foundation.JSONEncoder
 import NIO
@@ -130,3 +131,17 @@ extension JSONEncoder: LambdaCodableEncoder {
         return buffer
     }
 }
+
+extension JSONEncoder {
+    /// Convenience method to allow encoding json directly into a `String`. It can be used to encode a payload into an `APIGateway.V2.Response`'s body.
+    public func encodeAsString<T: Encodable>(_ value: T) throws -> String {
+        try String(decoding: self.encode(value), as: Unicode.UTF8.self)
+    }
+}
+
+extension JSONDecoder {
+    /// Convenience method to allow decoding json directly from a `String`. It can be used to decode a payload from an `APIGateway.V2.Request`'s body.
+    public func decode<T: Decodable>(_ type: T.Type, from string: String) throws -> T {
+        try self.decode(type, from: Data(string.utf8))
+    }
+}