Implement GzipServerMiddleware

Sources/GzipMiddleware/GzipMiddleware.swift

@@ -1,47 +1,15 @@
 import HTTP
 import Vapor
-import gzip
 import Foundation
-
-public enum GzipMiddlewareError: Error {
-    case unsupportedStreamType
-}
-
-/// Client Gzip middlere:
-/// 1. sets the "Accept-Encoding" header to "gzip"
-/// 2. if the response has "Content-Encoding" == "gzip", uncompresses the body
-public struct GzipClientMiddleware: Middleware {
-
-    public init() { }
-
-    public func respond(to request: Request, chainingTo next: Responder) throws -> Response {
-
-        request.headers["Accept-Encoding"] = "gzip"
-
-        let response = try next.respond(to: request)
-
-        guard response.headers["Content-Encoding"] == "gzip" else {
-            return response
-        }
-
-        let zipped = response.body
-        switch zipped {
-        case .data(let bytes):
-            response.body = .data(Array(try Data(bytes: bytes).gzipUncompressed()))
-        case .chunked(let chunker):
-            response.body = .chunked({ (stream: ChunkStream) in
-                let gzipStream = try GzipStream(mode: .uncompress, stream: stream.raw)
-                try chunker(ChunkStream(stream: gzipStream))
-            })
-        }
-        return response
-    }
-}
+import ZIPFoundation
 
 /// Server Gzip middlere:
 /// 1. checks if the "Accept-Encoding" header contains "gzip"
 /// 2. if so, compresses the body and sets the response header "Content-Encoding" to "gzip",
-public struct GzipServerMiddleware: Middleware {
+public struct GzipServerMiddleware: Middleware, ServiceType {
+    public static func makeService(for worker: Container) throws -> GzipServerMiddleware {
+        return .init()
+    }
 
     private let shouldGzip: (_ request: Request) -> Bool
 
@@ -51,26 +19,48 @@ public struct GzipServerMiddleware: Middleware {
         self.shouldGzip = shouldGzip
     }
 
-    public func respond(to request: Request, chainingTo next: Responder) throws -> Response {
-
-        let acceptsGzip = request.headers["Accept-Encoding"]?.contains("gzip") == true
+    public func respond(to request: Request, chainingTo next: Responder) throws -> EventLoopFuture<Response> {
+        let acceptsGzip = request.http.headers[.acceptEncoding].first?.contains("gzip") ?? false
         guard acceptsGzip && shouldGzip(request) else {
             return try next.respond(to: request)
         }
 
         let response = try next.respond(to: request)
-        response.headers["Content-Encoding"] = "gzip"
-
-        let unzipped = response.body
-        switch unzipped {
-        case .data(let bytes):
-            response.body = .data(Array(try Data(bytes: bytes).gzipCompressed()))
-        case .chunked(let chunker):
-            response.body = .chunked({ (stream: ChunkStream) in
-                let gzipStream = try GzipStream(mode: .compress, stream: stream.raw)
-                try chunker(ChunkStream(stream: gzipStream))
-            })
+        return response.flatMap { response in
+            var headers = response.http.headers
+            headers.replaceOrAdd(name: .contentEncoding, value: "gzip")
+            return response.http.body.consumeData(on: request).map { data in
+                let stream  = HTTPChunkedStream(on: request)
+                let bufSize = 4096
+                var buffer  = ByteBufferAllocator().buffer(capacity: bufSize)
+                let header  : [UInt8] = [0x1f, 0x8b, 0x08, 0x00]
+                let header2 : [UInt8] = [0x00, 0x03]
+                buffer.write(bytes: header)
+                buffer.write(integer: UInt32(Date().timeIntervalSince1970), endianness: .little)
+                buffer.write(bytes: header2)
+                var write   = stream.write(.chunk(buffer))
+                let crc32   = try Data.compress(size: data.count, bufferSize: bufSize,
+                    provider: {(offset, readSize) -> Data in
+                        return data.subdata(in: offset..<offset+readSize)
+                    },
+                    consumer: { data -> Void in
+                        write = write.flatMap {
+                            buffer.clear()
+                            buffer.write(bytes: data)
+                            return stream.write(.chunk(buffer))
+                        }
+                    })
+                write.always {
+                    buffer.clear()
+                    buffer.write(integer: crc32, endianness: .little)
+                    buffer.write(integer: UInt32(data.count), endianness: .little)
+                    stream.write(.chunk(buffer)).always {
+                        _ = stream.write(.end)
+                    }
+                }
+                let httpResponse = HTTPResponse(status: response.http.status, headers: headers, body: stream)
+                return request.response(http: httpResponse)
+            }
         }
-        return response
     }
 }