IOS SDK中的FTP上传流打开错误

Question

我尝试使用Apple's Sample code在FTP服务器上传图像。

但是我收到的错误如下： Stream Open Error 。

我认为模式存在问题（主动/被动）。但我怎么改变它？

我的服务器处于被动模式。

我不知道为什么会这样？

帮我解决这个问题。

我的代码如下：

- (void)startSend:(NSString *)filePath
{

    NSLog(@"%@",filePath);
    NSLog(@"%@ %@ %@",self.usernameText.text,self.urlText.text,self.passwordText.text);


    BOOL                    success;
    NSURL *                 url;

    assert(filePath != nil);
    assert([[NSFileManager defaultManager] fileExistsAtPath:filePath]);
    assert( [filePath.pathExtension isEqual:@"png"] || [filePath.pathExtension isEqual:@"jpg"] );

    assert(self.networkStream == nil);      // don't tap send twice in a row!
    assert(self.fileStream == nil);         // ditto

    // First get and check the URL.

    url = [[NetworkManager sharedInstance] smartURLForString:self.urlText.text];
    success = (url != nil);

    if (success) {
        // Add the last part of the file name to the end of the URL to form the final 
        // URL that we're going to put to.

        url = CFBridgingRelease(
            CFURLCreateCopyAppendingPathComponent(NULL, (__bridge CFURLRef) url, (__bridge CFStringRef) [filePath lastPathComponent], false)
        );
        success = (url != nil);
    }

    // If the URL is bogus, let the user know.  Otherwise kick off the connection.

    if ( ! success) {
        self.statusLabel.text = @"Invalid URL";
    } else {

        // Open a stream for the file we're going to send.  We do not open this stream; 
        // NSURLConnection will do it for us.

        self.fileStream = [NSInputStream inputStreamWithFileAtPath:filePath];
        assert(self.fileStream != nil);

       [self.fileStream open];

        // Open a CFFTPStream for the URL.

        self.networkStream = CFBridgingRelease(
            CFWriteStreamCreateWithFTPURL(NULL, (__bridge CFURLRef) url)
        );
        assert(self.networkStream != nil);

        if ([self.usernameText.text length] != 0) {
            success = [self.networkStream setProperty:self.usernameText.text forKey:(id)kCFStreamPropertyFTPUserName];
            assert(success);
            success = [self.networkStream setProperty:self.passwordText.text forKey:(id)kCFStreamPropertyFTPPassword];
            assert(success);
        }

        self.networkStream.delegate = self;

       // [self.networkStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        [self.networkStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        [self.networkStream open];

        // Tell the UI we're sending.

        [self sendDidStart];
    }
}


- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
    // An NSStream delegate callback that's called when events happen on our 
    // network stream.
{
    #pragma unused(aStream)
    assert(aStream == self.networkStream);

    switch (eventCode) {

            NSLog(@"%u",eventCode);

        case NSStreamEventOpenCompleted: {
            [self updateStatus:@"Opened connection"];
        } break;
        case NSStreamEventHasBytesAvailable: {
            [self.fileStream open];
            assert(NO);     // should never happen for the output stream
        } break;
        case NSStreamEventHasSpaceAvailable: {
            [self updateStatus:@"Sending"];

            // If we don't have any data buffered, go read the next chunk of data.

            if (self.bufferOffset == self.bufferLimit) {
                NSInteger   bytesRead;

                bytesRead = [self.fileStream read:self.buffer maxLength:kSendBufferSize];

                if (bytesRead == -1) {
                    [self stopSendWithStatus:@"File read error"];
                } else if (bytesRead == 0) {
                    [self stopSendWithStatus:nil];
                } else {
                    self.bufferOffset = 0;
                    self.bufferLimit  = bytesRead;
                }
            }

            // If we're not out of data completely, send the next chunk.

            if (self.bufferOffset != self.bufferLimit) {
                NSInteger   bytesWritten;
                bytesWritten = [self.networkStream write:&self.buffer[self.bufferOffset] maxLength:self.bufferLimit - self.bufferOffset];
                assert(bytesWritten != 0);
                if (bytesWritten == -1) {
                    [self stopSendWithStatus:@"Network write error"];
                } else {
                    self.bufferOffset += bytesWritten;
                }
            }
        } break;
        case NSStreamEventErrorOccurred: {
            [self stopSendWithStatus:@"Stream open error"];
        } break;
        case NSStreamEventEndEncountered: {
            // ignore
        } break;
        default: {
            assert(NO);
        } break;
    }
}