我是新的iOS程序员。
我想将 Assets 库中的大文件(视频或图片)上传到服务器中，
我的原始方法是只使用 NSMutableURLRequest 并将 NSData (大视频或大图像)附加到它，然后在以下代码中发生崩溃:

    ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *asset){
        //.......some code I just skip it...
        ALAssetRepresentation *rep = [asset defaultRepresentation];
        void *buffer = [rawData mutableBytes];
        [rep getBytes:buffer fromOffset:0 length:size error:nil];
        NSData *videoData = [[NSData alloc] initWithBytes:buffer length:size];//crash here
        [self startUploading:videoData];
    }

-(NSInputStream *)connection:(NSURLConnection *)connection needNewBodyStream:(NSURLRequest *)request
{
    [NSThread sleepForTimeInterval:2];
    NSInputStream *fileStream = [NSInputStream inputStreamWithFileAtPath:pathToBodyFile];
    if (fileStream == nil) {
        NSLog(@"NSURLConnection was asked to retransmit a new body stream for a request. returning nil!");
    }
    return fileStream;
}

最佳答案

假设您的数据太大而无法容纳到内存中:

一种有效且可靠的方法将利用有限的CFStream对(请参阅CFStreamCreateBoundPair)。

绑定(bind)流对的输入流设置为NSMutableURLRequest的HTTPBodyStream属性。有界流对的输出流将用于写入从固定大小的内存缓冲区(已用ALAssetRepresentation的getBytes:fromOffset:length:error:方法填充)获得的字节。

有界流对的传输缓冲区的大小应与 Assets 表示形式的缓冲区的大小相同。

设置代码将需要几行代码，并且需要使用NSStreams并具有处理事件的经验(NSStreams通常有一些微妙之处)。

此方法的工作方式如下:

    _buffer = (uint8_t)malloc(_bufferSize);
    _buffer_end = _buffer + _bufferSize;
    _p = _buffer;
    CFReadStreamRef readStream = NULL;
    CFWriteStreamRef writeStream = NULL;
    CFStreamCreateBoundPair(NULL, &readStream, &writeStream, _bufferSize);
    self.inputStream = CFBridgingRelease(readStream);
    self.internalOutputStream = CFBridgingRelease(writeStream);        

    [self.internalOutputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:self.runLoopMode];
    [self.internalOutputStream open];
    // (Note: inputStream will be opened and scheduled by the request!)

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent
{
    if (_isCancelled) {
        return;
    }
    switch (streamEvent) {
        case NSStreamEventNone:
            break;
        case NSStreamEventOpenCompleted:
            DLogInfo(@"internal output stream: open completed");
            break;
        case NSStreamEventHasBytesAvailable:
            // n.a.
            NSAssert(0, @"bogus stream event");
            break;
        case NSStreamEventHasSpaceAvailable:
            NSAssert(theStream == _internalOutputStream, @"bogus stream event");
            DLogInfo(@"destination stream: has space available");
            [self write];
            break;
        case NSStreamEventErrorOccurred:
            DLogInfo(@"destination stream: error occurred");
            [self finish];
            break;
        case NSStreamEventEndEncountered:
            // weird error: the output stream is full or closed prematurely, or canceled.
            DLogWarn(@"destination stream: EOF encountered");
            if (_result == nil) {
                self.result = [NSError errorWithDomain:NSStringFromClass([self class])
                                                  code:-2
                                              userInfo:@{NSLocalizedDescriptionKey: @"output stream EOF encountered"}];
            }
            [self finish];
            break;
    }
}

关于ios - iOS如何通过流式传输将大型 Assets 文件上传到服务器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18348863/