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我正在开发一个网络摄像头查看器，对于这些摄像头：http: //www.canvision.net/support/pt300-cgi/GetData.htm 数据是这样到达的： 

HTTP/1.0 200 OK
Date: Wed, 19 Feb 2003 03:40:16 GMT
Server: WYM/1.0
Connection: close
Content-Type: multipart/x-mixed-replace;boundary=WINBONDBOUDARY
Last-Modified: Wed, 19 Feb 2003 03:40:16 GMT
Pragma: no-cache
Cache-Control: no-cache
Expires: 01 Jan 1970 00:00:00 GMT
--WINBONDBOUDARY
Content-Type: image/jpeg

--WINBONDBOUDARY
Content-Type: image/jpeg

这些是我的 NSURLConnection 委托方法： 

- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)data
{
     [currentData appendData:data];
}



    

  • (void)connection:(NSURLConnection *)theConnection didReceiveResponse:(NSURLResponse *)response{
 NSLog(@"response with mime: %@ length:%i",[response MIMEType],[currentData length]);
 if([[response MIMEType] isEqualToString:@"image/jpeg"] && [currentData length] != 0){
      currentFrame = [UIImage imageWithData:currentData];
      NSLog(@"valid frame");
      [image setImage:currentFrame];
      frameCounter++;
 }
 else {
      NSLog(@"other data:%@",currentData);
 }
 currentFrame = nil;
 if (currentData == receivedData1)//swap buffers
    currentData = receivedData2;
    
else
    currentData = receivedData1;
    
 [currentData setLength:0];
 [currentFrame release];
}
这一切都很好，控制台输出看起来像你期望的那样： 

[Session started at 2011-02-21 20:20:39 +0100.]
2011-02-21 20:20:43.237 MotionJPEG[16330:207] response with mime: multipart/x-mixed-replace length:0
2011-02-21 20:20:43.261 MotionJPEG[16330:207] other data:<>
2011-02-21 20:20:43.262 MotionJPEG[16330:207] response with mime: image/jpeg length:0
2011-02-21 20:20:43.263 MotionJPEG[16330:207] other data:<>
2011-02-21 20:20:43.340 MotionJPEG[16330:207] response with mime: image/jpeg length:4608
2011-02-21 20:20:43.340 MotionJPEG[16330:207] valid frame
2011-02-21 20:20:43.445 MotionJPEG[16330:207] response with mime: image/jpeg length:4600
2011-02-21 20:20:43.446 MotionJPEG[16330:207] valid frame
2011-02-21 20:20:43.544 MotionJPEG[16330:207] response with mime: image/jpeg length:4580
2011-02-21 20:20:43.545 MotionJPEG[16330:207] valid frame

但是，Cam 支持另一种模式，其中附加信息嵌入在 jpeg 之间：

HTTP/1.0 200 OK
Date: Wed, 19 Feb 2003 03:40:16 GMT
Server: WYM/1.0
Connection: close
Content-Type: multipart/x-mixed-replace;boundary=WINBONDBOUDARY
Last-Modified: Wed, 19 Feb 2003 03:40:16 GMT
Pragma: no-cache
Cache-Control: no-cache
Expires: 01 Jan 1970 00:00:00 GMT
--WINBONDBOUDARY
Content-Type: image/jpeg

--WINBONDBOUDARY
Content-Type: text/plain

--WINBONDBOUDARY
Content-Type: image/jpeg

--WINBONDBOUDARY
Content-Type: text/plain

在这种模式下，我希望代码可以正常工作，并且 text/plain 部分将由

NSLog(@"other data:%@",currentData);

线。但是，由于某种原因，输出看起来完全一样，它从来没有用 mime: text/plain 表示响应，而是将纯文本部分附加到 jpeg 中，并且 UIImageView 无法显示数据。为什么 NSURLConnection 不能识别 text/plain 部分？这是完整的来源：http ://renehopf.de/MotionJPEG.zip 但要重现问题，您需要相同的网络摄像头...

谢谢，

雷内

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