[Message] Unify Request & Response coding

Author: tonyfreeman

Sources/HTTP/Client/Client.swift

@@ -2,7 +2,6 @@ import Log
 import URL
 import Network
 import Stream
-import DCompression
 
 public class Client {
     public var bufferSize = 4096
@@ -77,7 +76,7 @@ public class Client {
         try await outputStream.flush()
 
         var response = try await Response.decode(from: inputStream)
-        try await decode(&response)
+        try await Coder.decode(&response)
         return response
     }
 
@@ -108,25 +107,6 @@ public class Client {
         }
         request.acceptEncoding = acceptEncoding
     }
-
-    private func decode(_ response: inout Response) async throws {
-        guard let contentEncoding = response.contentEncoding else {
-            return
-        }
-        // FIXME: use GZip/Deflate stream
-        // instead of changing contentLength
-        let bytes = try await response.readBody()
-        let stream = InputByteStream(bytes)
-        if contentEncoding.contains(.gzip) {
-            let bytes = try await GZip.decode(from: stream)
-            response.body = .input(bytes)
-            response.contentLength = bytes.count
-        } else if contentEncoding.contains(.deflate) {
-            let bytes = try await Deflate.decode(from: stream)
-            response.body = .input(bytes)
-            response.contentLength = bytes.count
-        }
-    }
 }
 
 extension Client {

Sources/HTTP/Coding/CodableMessage.swift

@@ -2,13 +2,20 @@ import Stream
 
 public protocol DecodableMessage: AnyObject {
     var contentType: ContentType? { get }
+    var contentEncoding: [ContentEncoding]? { get }
     var transferEncoding: [TransferEncoding]? { get }
-    var contentLength: Int? { get }
+    var contentLength: Int? { get set }
     var body: Body { get set }
 }
 
-extension Request: DecodableMessage {}
-extension Response: DecodableMessage {}
+public protocol EncodableMessage: AnyObject {
+    var contentType: ContentType? { get set }
+    var contentLength: Int? { get set }
+    var body: Body { get set }
+}
+
+extension Request: DecodableMessage, EncodableMessage {}
+extension Response: DecodableMessage, EncodableMessage {}
 
 extension DecodableMessage {
     public func readBody() async throws -> [UInt8] {

Sources/HTTP/Coding/Coder.swift

@@ -2,6 +2,7 @@ import URL
 import JSON
 import Stream
 import Network
+import DCompression
 
 // MARK: Coder
 
@@ -59,24 +60,24 @@ public struct Coder {
     }
 
     @usableFromInline
-    static func encode(
+    static func encode<Message: EncodableMessage>(
         object: Encodable,
-        to response: Response,
+        to message: Message,
         contentType type: ApplicationSubtype) throws
     {
         switch type {
         case .json:
             // TODO: Use stream + chunked?
             let bytes = try JSON.encode(encodable: object)
-            response.body = .output(bytes)
-            response.contentLength = bytes.count
-            response.contentType = .json
+            message.body = .output(bytes)
+            message.contentLength = bytes.count
+            message.contentType = .json
 
         case .formURLEncoded:
             let bytes = try FormURLEncoded.encode(encodable: object)
-            response.body = .output(bytes)
-            response.contentLength = bytes.count
-            response.contentType = .formURLEncoded
+            message.body = .output(bytes)
+            message.contentLength = bytes.count
+            message.contentType = .formURLEncoded
 
         default:
             throw HTTP.Error.unsupportedContentType
@@ -171,3 +172,25 @@ public struct Coder {
         return try type.init(from: decoder)
     }
 }
+
+// GZip, Deflate
+extension Coder {
+    static func decode<Message: DecodableMessage>(_ message: inout Message) async throws {
+        guard let contentEncoding = message.contentEncoding else {
+            return
+        }
+        // FIXME: use GZip/Deflate stream
+        // instead of changing contentLength
+        let bytes = try await message.readBody()
+        let stream = InputByteStream(bytes)
+        if contentEncoding.contains(.gzip) {
+            let bytes = try await GZip.decode(from: stream)
+            message.body = .input(bytes)
+            message.contentLength = bytes.count
+        } else if contentEncoding.contains(.deflate) {
+            let bytes = try await Deflate.decode(from: stream)
+            message.body = .input(bytes)
+            message.contentLength = bytes.count
+        }
+    }
+}

Sources/HTTP/Message/Request/Request.swift

@@ -63,22 +63,6 @@ extension Request {
         contentType type: ApplicationSubtype = .json
     ) throws {
         self.init(url: url, method: method)
-
-        switch type {
-        case .json:
-            let bytes = try JSON.encode(body)
-            self.contentType = .json
-            self.body = .output(bytes)
-            self.contentLength = bytes.count
-
-        case .formURLEncoded:
-            let bytes = try FormURLEncoded.encode(body)
-            self.contentType = .formURLEncoded
-            self.body = .output(bytes)
-            self.contentLength = bytes.count
-
-        default:
-            throw Error.unsupportedContentType
-        }
+        try Coder.encode(object: body, to: self, contentType: type)
     }
 }