NSLocalizedDescription for http errors

Author: johnno1962

CoreFoundation/URL.subproj/CFURLSessionInterface.c

@@ -31,6 +31,10 @@ static CFURLSessionMultiCode MakeMultiCode(CURLMcode value) {
     return (CFURLSessionMultiCode) { value };
 }
 
+const char *CFURLSessionErrorDescription(int value) {
+    return curl_easy_strerror(value);
+}
+
 
 CFURLSessionEasyHandle _Nonnull CFURLSessionEasyHandleInit() {
     return curl_easy_init();

CoreFoundation/URL.subproj/CFURLSessionInterface.h

@@ -48,6 +48,8 @@ typedef struct CFURLSessionEasyCode {
     int value;
 } CFURLSessionEasyCode;
 
+CF_EXPORT const char * _Nonnull CFURLSessionErrorDescription(int value);
+
 /// CURLcode
 CF_EXPORT CFURLSessionEasyCode const CFURLSessionEasyCodeOK; // CURLE_OK
 CF_EXPORT CFURLSessionEasyCode const CFURLSessionEasyCodeUNSUPPORTED_PROTOCOL; // CURLE_UNSUPPORTED_PROTOCOL

Foundation/URLSession/http/EasyHandle.swift

@@ -56,6 +56,7 @@ internal final class _EasyHandle {
     fileprivate var headerList: _CurlStringList?
     fileprivate var pauseState: _PauseState = []
     internal var timeoutTimer: _TimeoutSource!
+    private var errorBuffer = [UInt8](repeating: 0, count: 1000)
     #if os(Android)
     static fileprivate var _CAInfoFile: UnsafeMutablePointer<Int8>?
     #endif
@@ -89,8 +90,8 @@ extension _EasyHandle {
 }
 
 internal extension _EasyHandle {
-    func completedTransfer(withErrorCode errorCode: Int?) {
-        delegate?.transferCompleted(withErrorCode: errorCode)
+    func completedTransfer(withErrorInfo errorInfo: URLErrorInfo?) {
+        delegate?.transferCompleted(withErrorInfo: errorInfo)
     }
 }
 internal protocol _EasyHandleDelegate: class {
@@ -107,7 +108,7 @@ internal protocol _EasyHandleDelegate: class {
     func fill(writeBuffer buffer: UnsafeMutableBufferPointer<Int8>) -> _EasyHandle._WriteBufferResult
     /// The transfer for this handle completed.
     /// - parameter errorCode: An NSURLError code, or `nil` if no error occured.
-    func transferCompleted(withErrorCode errorCode: Int?)
+    func transferCompleted(withErrorInfo errorInfo: URLErrorInfo?)
     /// Seek the input stream to the given position
     func seekInputStream(to position: UInt64) throws
     /// Gets called during the transfer to update progress.
@@ -170,6 +171,9 @@ extension _EasyHandle {
         let protocols = (CFURLSessionProtocolHTTP | CFURLSessionProtocolHTTPS)
         try! CFURLSession_easy_setopt_long(rawHandle, CFURLSessionOptionPROTOCOLS, protocols).asError()
         try! CFURLSession_easy_setopt_long(rawHandle, CFURLSessionOptionREDIR_PROTOCOLS, protocols).asError()
+        errorBuffer.withUnsafeMutableBufferPointer {
+            try! CFURLSession_easy_setopt_ptr(rawHandle, CFURLSessionOptionERRORBUFFER, $0.baseAddress).asError()
+        }
         #if os(Android)
             // See https://curl.haxx.se/docs/sslcerts.html
             // For SSL to work you need "cacert.pem" to be accessable

Foundation/URLSession/http/HTTPURLProtocol.swift

@@ -136,7 +136,7 @@ fileprivate extension _HTTPURLProtocol {
             //     NSURLErrorNoPermissionsToReadFile
             //     NSURLErrorFileDoesNotExist
             self.internalState = .transferFailed
-            failWith(errorCode: errorCode(fileSystemError: e), request: request)
+            failWith(errorCode: errorCode(fileSystemError: e), errorDescription: "File system error", request: request)
             return
         }
 
@@ -330,12 +330,13 @@ internal extension _HTTPURLProtocol {
         case stream(InputStream)
     }
 
-    func failWith(errorCode: Int, request: URLRequest) {
+    func failWith(errorCode: Int, errorDescription: String?, request: URLRequest) {
         //TODO: Error handling
         let userInfo: [String : Any]? = request.url.map {
             [
                 NSURLErrorFailingURLErrorKey: $0,
                 NSURLErrorFailingURLStringErrorKey: $0.absoluteString,
+                NSLocalizedDescriptionKey: errorDescription ?? "Unknown http error",
                 ]
         }
         let error = URLError(_nsError: NSError(domain: NSURLErrorDomain, code: errorCode, userInfo: userInfo))
@@ -530,16 +531,16 @@ extension _HTTPURLProtocol: _EasyHandleDelegate {
         }
     }
 
-    func transferCompleted(withErrorCode errorCode: Int?) {
+    func transferCompleted(withErrorInfo errorInfo: URLErrorInfo?) {
         // At this point the transfer is complete and we can decide what to do.
         // If everything went well, we will simply forward the resulting data
         // to the delegate. But in case of redirects etc. we might send another
         // request.
         guard case .transferInProgress(let ts) = internalState else { fatalError("Transfer completed, but it wasn't in progress.") }
         guard let request = task?.currentRequest else { fatalError("Transfer completed, but there's no current request.") }
-        guard errorCode == nil else {
+        guard errorInfo == nil else {
             internalState = .transferFailed
-            failWith(errorCode: errorCode!, request: request)
+            failWith(errorCode: errorInfo!.code, errorDescription: errorInfo!.description, request: request)
             return
         }
 
@@ -557,7 +558,7 @@ extension _HTTPURLProtocol: _EasyHandleDelegate {
             completeTask()
         case .failWithError(let errorCode):
             internalState = .transferFailed
-            failWith(errorCode: errorCode, request: request)
+            failWith(errorCode: errorCode, errorDescription: "Completion failure", request: request)
         case .redirectWithRequest(let newRequest):
             redirectFor(request: newRequest)
         }
@@ -575,6 +576,10 @@ extension _HTTPURLProtocol: _EasyHandleDelegate {
     }
 }
 
+internal struct URLErrorInfo {
+    let code: Int, description: String?
+}
+
 extension _HTTPURLProtocol {
     /// The is independent of the public `state: URLSessionTask.State`.
     enum _InternalState {

Foundation/URLSession/http/MultiHandle.swift

@@ -214,12 +214,14 @@ fileprivate extension URLSession._MultiHandle {
         }
         let easyHandle = easyHandles[idx]
         // Find the NSURLError code
-        let errorCode = easyHandle.urlErrorCode(for: easyCode)
-        completedTransfer(forEasyHandle: easyHandle, errorCode: errorCode)
+        let errorInfo = easyHandle.urlErrorCode(for: easyCode).map {
+            URLErrorInfo(code: $0, description: String(cString: CFURLSessionErrorDescription(easyCode.value)))
+        }
+        completedTransfer(forEasyHandle: easyHandle, errorInfo: errorInfo)
     }
     /// Transfer completed.
-    func completedTransfer(forEasyHandle handle: _EasyHandle, errorCode: Int?) {
-        handle.completedTransfer(withErrorCode: errorCode)
+    func completedTransfer(forEasyHandle handle: _EasyHandle, errorInfo: URLErrorInfo?) {
+        handle.completedTransfer(withErrorInfo: errorInfo)
     }
 }