Add headers.contains(...) method and make use of it in HTTPRequestEnc…

…oder + minimize access to headers in encoder when possible

Sources/NIOHTTP1/HTTPEncoder.swift

@@ -82,10 +82,6 @@ private func writeHead(wrapOutboundOut: (IOData) -> NIOAny, writeStartLine: (ino
     ctx.write(wrapOutboundOut(.byteBuffer(buffer)), promise: promise)
 }
 
-private func isChunkedPart(_ headers: HTTPHeaders) -> Bool {
-    return headers["transfer-encoding"].contains("chunked")
-}
-
 /// Adjusts the response/request headers to ensure that the response/request will be well-framed.
 ///
 /// This method strips Content-Length and Transfer-Encoding headers from responses/requests that must
@@ -95,16 +91,23 @@ private func isChunkedPart(_ headers: HTTPHeaders) -> Bool {
 ///
 /// Note that for HTTP/1.0 if there is no Content-Length then the response should be followed
 /// by connection close. We require that the user send that connection close: we don't do it.
-private func sanitizeTransportHeaders(hasBody: HTTPMethod.HasBody, headers: inout HTTPHeaders, version: HTTPVersion) {
+///
+/// Returns true if its chunked.
+private func sanitizeTransportHeaders(hasBody: HTTPMethod.HasBody, headers: inout HTTPHeaders, version: HTTPVersion) -> Bool {
     switch hasBody {
     case .no:
         headers.remove(name: "content-length")
         headers.remove(name: "transfer-encoding")
-    case .yes where headers["content-length"].count == 0 && version.major == 1 && version.minor >= 1:
+        return false
+    case .yes where version.major == 1 && version.minor >= 1:
+        if headers.contains(name: "content-length") {
+            return false
+        }
         headers.replaceOrAdd(name: "transfer-encoding", value: "chunked")
+        return true
     case .yes, .unlikely:
         /* leave alone */
-        ()
+        return headers.contains(name: "transfer-encoding", value: "chunked")
     }
 }
 
@@ -123,9 +126,8 @@ public final class HTTPRequestEncoder: ChannelOutboundHandler {
     public func write(ctx: ChannelHandlerContext, data: NIOAny, promise: EventLoopPromise<Void>?) {
         switch self.unwrapOutboundIn(data) {
         case .head(var request):
-            sanitizeTransportHeaders(hasBody: request.method.hasRequestBody, headers: &request.headers, version: request.version)
 
-            self.isChunked = isChunkedPart(request.headers)
+            self.isChunked = sanitizeTransportHeaders(hasBody: request.method.hasRequestBody, headers: &request.headers, version: request.version)
 
             writeHead(wrapOutboundOut: self.wrapOutboundOut, writeStartLine: { buffer in
                 request.method.write(buffer: &buffer)
@@ -158,9 +160,9 @@ public final class HTTPResponseEncoder: ChannelOutboundHandler {
     public func write(ctx: ChannelHandlerContext, data: NIOAny, promise: EventLoopPromise<Void>?) {
         switch self.unwrapOutboundIn(data) {
         case .head(var response):
-            sanitizeTransportHeaders(hasBody: response.status.mayHaveResponseBody ? .yes : .no, headers: &response.headers, version: response.version)
 
-            self.isChunked = isChunkedPart(response.headers)
+            self.isChunked = sanitizeTransportHeaders(hasBody: response.status.mayHaveResponseBody ? .yes : .no, headers: &response.headers, version: response.version)
+
             writeHead(wrapOutboundOut: self.wrapOutboundOut, writeStartLine: { buffer in
                 response.version.write(buffer: &buffer)
                 buffer.write(staticString: " ")

Sources/NIOHTTP1/HTTPTypes.swift

@@ -354,6 +354,30 @@ public struct HTTPHeaders: CustomStringConvertible {
         return array
     }
 
+    /// Checks if a header is present
+    ///
+    /// - parameters:
+    ///     - name: The name of the header
+    ///     - value: The value of the header or nil if the name should not be checked
+    //  - returns: `true` if a header with the name (and value) exists, `false` otherwise.
+    public func contains(name: String, value: String? = nil) -> Bool {
+        guard !self.headers.isEmpty else {
+            return false
+        }
+
+        let utf8 = name.utf8
+        let stringLength = utf8.count
+        for header in headers {
+            if stringLength == header.name.length && self.buffer.equalCaseInsensitiveASCII(seq: utf8, at: header.name) {
+                if let value = value {
+                    return value.count == header.value.length && self.buffer.getString(at: header.value.start, length: header.value.length) == value
+                }
+                return true
+            }
+        }
+        return false
+    }
+
     /// Serializes this HTTP header block to bytes suitable for writing to the wire.
     ///
     /// - Parameter buffer: A buffer to write the serialized bytes into. Will increment