POSIX错误12（“不能分配内存”），而从iPhone上传文件

我正在开发一个iPhone应用程序，其中包括从相机上传完整照片（一般在1.5到2.0 MB之间）以及缩略图（小得多）到Amazon S3。

缩略图总是成功上传，但有时全部图像不会，而且当失败时，它们会以POSIX错误代码12，即ENOMEM失败。但是，我添加了debugging代码来打印错误发生时的可用内存量，总是有相当多的空闲空间，通常超过100 MB。

此外，当上传发生在3G上的时候，这个错误会更频繁地出现，而当它上传到wifi上的时候，这种错误会更加频繁 – 这似乎很奇怪，因为请求没有被下载太多，上传的文件已经在内存中了stream媒体从磁盘没有改善）。

我已经尝试使用NSURLConnection，Foundation CFHTTP *函数和ASIHTTPRequest库来上传文件，但无论如何，错误都是以相同的频率发生的。更奇怪的是，我的所有Googlesearch都显示，最终用户有时会从Safari获取错误代码12 – 我还没有看到任何iOS开发人员提到它。我正在使用一个inheritance的代码库，所以有可能是有问题的，但我甚至不知道要找什么。任何有识之士将不胜感激！

我能够解决此问题的唯一方法是直接使用套接字并手动形成HTTP标头。所以我的上传代码目前看起来像这样：

- (void)socketClose { [_inputStream setDelegate:nil]; [_inputStream close]; [_inputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; SCR_RELEASE_SAFELY(_inputStream); [_outputStream setDelegate:nil]; [_outputStream close]; [_outputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; SCR_RELEASE_SAFELY(_outputStream); SCR_RELEASE_SAFELY(_headerBuffer); } - (void)sendRequest { [self socketClose]; SCR_RELEASE_SAFELY(_headerBuffer); if (!_shouldCancel) { NSString *httpMessage = [NSString stringWithFormat:@"POST upload.php HTTP/1.1\r\n" "Host:" #ifndef TESTBED " %@" #endif "\r\n" "User-Agent: MyApp/3.0.0 CFNetwork/534 Darwin/10.7.0\r\n" "Content-Length: %d\r\n" "Accept: */*\r\n" "Accept-Language: en-us\r\n" "Accept-Encoding: gzip, deflate\r\n" "Content-Type: application/x-www-form-urlencoded\r\n" "Connection: keep-alive\r\n\r\n" "data=" #ifndef TESTBED , [self.serverUrl host] #endif , _bytesToUpload]; NSString *key = @"data="; NSData *keyData = [key dataUsingEncoding:NSASCIIStringEncoding]; _bytesToUpload -= [keyData length]; _bytesToUpload = MAX(0, _bytesToUpload); _headerBuffer = [[NSMutableData alloc] initWithData:[httpMessage dataUsingEncoding:NSUTF8StringEncoding]]; _writtenDataBytes = 0; CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault , (CFStringRef)[self.serverUrl host] #ifdef TESTBED , 8888 #else , 80 #endif , (CFReadStreamRef *)(&_inputStream) , (CFWriteStreamRef *)(&_outputStream)); [_inputStream setDelegate:self]; [_outputStream setDelegate:self]; [_inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [_outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [_inputStream open]; [_outputStream open]; } } - (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent { if (_outputStream == theStream) { switch (streamEvent) { case NSStreamEventOpenCompleted: { [self regenerateTimeoutTimer]; break; } case NSStreamEventHasSpaceAvailable: { SCR_RELEASE_TIMER(_timeoutTimer); NSInteger length = _headerBuffer.length; if (length > 0) { NSInteger written = [_outputStream write:(const uint8_t *)[_headerBuffer bytes] maxLength:length]; NSInteger rest = length - written; if (rest > 0) { memmove([_headerBuffer mutableBytes], (const uint8_t *)[_headerBuffer mutableBytes] + written, rest); } [_headerBuffer setLength:rest]; } else { const uint8_t *dataBytes = [_data bytes]; while ([_outputStream hasSpaceAvailable] && (_writtenDataBytes < _bytesToUpload)) { NSInteger written = [_outputStream write:dataBytes maxLength:MIN(_dataLength, _bytesToUpload - _writtenDataBytes)]; if (written > 0) { _writtenDataBytes += written; } } } [self regenerateTimeoutTimer]; break; } case NSStreamEventErrorOccurred: { SCR_RELEASE_TIMER(_timeoutTimer); [self reportError:[theStream streamError]]; break; } case NSStreamEventEndEncountered: { SCR_RELEASE_TIMER(_timeoutTimer); [self socketClose]; break; } } } else if (_inputStream == theStream) { switch (streamEvent) { case NSStreamEventHasBytesAvailable: { SCR_RELEASE_TIMER(_timeoutTimer); /* Read server response here if you wish */ [self socketClose]; break; } case NSStreamEventErrorOccurred: { SCR_RELEASE_TIMER(_timeoutTimer); [self reportError:[theStream streamError]]; break; } case NSStreamEventEndEncountered: { SCR_RELEASE_TIMER(_timeoutTimer); [self socketClose]; break; } } } }

虽然ASIHTTPRequest可以在这里工作，但是我们决定摆脱这种依赖关系，以便获得性能，并准确地把所有东西都控制在我们自己的控制之下。你可以使用Wireshark工具来debugging这种事情。

解决此问题的关键是使用stream上载文件。当使用NSMutableURLRequest时，可以使用类似于以下内容的方法来完成：

 NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPBodyStream:[NSInputStream inputStreamWithFileAtPath:filePath]];

在使用ASIHTTPRequest时，stream式传输文件是通过以下方式完成的：

 ASIHTTPRequest* request = [ASIHTTPRequest requestWithURL:url]; [request setPostBodyFilePath:filePath]; rRequest.shouldStreamPostDataFromDisk = YES;

使用@autorelease{}为主函数使用请求操作（ NSMutableUrlConnection ）解决了此错误。 NSPOXIS有时只出现。

 - (void)main NSURLConnection* connection; @autoreleasepool //urgently needed for 3G upload { self.currentRequest = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"test.php"]]; [self.currentRequest setHTTPMethod:@"PUT"]; [self.currentRequest setHTTPBody:self.data];//inpustStream doesn't work connection = [NSURLConnection connectionWithRequest:self.currentRequest delegate:self]; [connection start]; }//end autorelease pool do { [[NSRunLoop currentRunLoop] runMode: NSDefaultRunLoopMode beforeDate: [NSDate distantFuture]]; if ([self isCancelled]) { connection = nil; isFailed = YES; break; } self.status(statusUpdateMessage); } while (!isFailed && !isCompleted); [timer invalidate];//test timer = nil; //corresponding of status via blocks self.completed(!isFailed); self.status(isFailed ? errorMessage : @"Completed"); if (isFailed) { self.failed(errorMessage != nil ? errorMessage : @"Undefined error"); } self.data = nil; self.currentRequest = nil; connection = nil; }