如何将数据存储在did-receive-data中的NS-Mutable-data中，然后写入文件

Question

我从2天卡住了，我想要显示downlaod进度条。 我发送json发送到服务器，并在响应服务器发送给我的视频数据。 要显示进度条我写像

一些逻辑代码在ASIhttep我正在与附加全球NSmutabledata和在请求做方法接收数据didreceivedata方法我写，全球Nsmutalbedata成文件。 但文件是空白的，它不会得到存储到文件。

我知道ASIHttprequest是旧图书馆，但每个人都建议我使用AFnetworking，但我不想更改代码，因为它会花费很多时间，我必须再次阅读文档。

任何人都可以帮助我如何追加数据，并在downlaod完成后将附加数据写入文件？

ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[[NSURL alloc] initWithString:@"http://testing.io/dev.php/video/verifyReceipt"]]; 

    [request setDidReceiveDataSelector:@selector(request:didReceiveData:)]; 
    [request setPostValue:resultAsString forKey:@"verify"]; 
    [request setDidFinishSelector:@selector(requestDone:)]; 
    [request setTimeOutSeconds:120]; 
    [request setDelegate:self]; 
    [request setNumberOfTimesToRetryOnTimeout:2]; 
    [request setDownloadProgressDelegate:progressBar]; 
    request.showAccurateProgress = YES; 

    [request startSynchronous]; 
    } 
    -(void)request:(ASIHTTPRequest *)request didReceiveData:(NSData *)data 
    { 
      [videoData appendData:data]; 
      NSLog(@"data is %@",data); 
    } 

    - (void)requestDone:(ASIHTTPRequest *)request 
    { 
    //[MBProgressHUD hideHUDForView:self.view animated:YES]; 

    // SAVED PDF PATH 
    // Get the Document directory 
     NSString *documentDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; 
    // Add your filename to the directory to create your saved pdf location 
    NSString* movLocation = [documentDirectory stringByAppendingPathComponent:[fileName stringByAppendingString:@".mov"]]; 

    if(request.responseStatusCode==200) 
    { 
     [videoData writeToFile:movLocation atomically:NO]; 
     NSLog(@"in request done sucsessfully downlaod and store in database %d",request.responseStatusCode); 
     [DBHelper savePurchaseId:fileName]; 
     [self movieReceived]; 
    } 
    else 
    {   
     NSLog(@"in request downlaod and store in database failed %@",request.responseHeaders); 

    } 
} 

Answer 1

对这样的任务使用异步请求会更好。您可以使用相同的ASIHTTPRequest类，但采用块方式。尝试编写类似于此的代码：

-(void) verifyReceipt { 
    NSURL *theURL = [NSURL URLWithString:@"http://testing.io/dev.php/video/verifyReceipt"]; 
    NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:theURL cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10.0f]; 
[theRequest setHTTPMethod:@"POST"]; 

    NSString *param1 = [self getParam1]; // getParam1 - some method to get useful data for request's body 
    NSNumber *param2 = [self getParam2]; 
    NSString *postString = [NSString stringWithFormat:@"param1=%@&param2=%@", param1, param2]; 

    [theRequest setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]]; 

    NSOperationQueue *queue = [[NSOperationQueue alloc] init]; 
    [NSURLConnection sendAsynchronousRequest:theRequest queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) 
    { 
     if ([data length] > 0 && error == nil) { 
      //[delegate receivedData:data]; // - if you want to notify some delegate about data arrival 
      NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; 
      NSString *filePath = [NSString stringWithFormat:@"%@/fileArrived.ext", rootPath]; 

      //try to access that local file for writing to it... 
      NSFileHandle *hFile = [NSFileHandle fileHandleForWritingAtPath:filePath]; 
      //did we succeed in opening the existing file? 
      if (!hFile) 
      { //nope->create that file! 
       [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil]; 
       //try to open it again... 
       hFile = [NSFileHandle fileHandleForWritingAtPath:filePath]; 
      } 
      //did we finally get an accessable file? 
      if (!hFile) 
      { //nope->bomb out! 
       NSLog(@"could not write to file %@", filePath); 
       return; 
      } 
      //we never know - hence we better catch possible exceptions! 
      @try 
      { 
       //seek to the end of the file 
       [hFile seekToEndOfFile]; 
       //finally write our data to it 
       [hFile writeData:data]; 
      } 
      @catch (NSException * e) 
      { 
       NSLog(@"exception when writing to file %@", filePath); 
      } 
      [hFile closeFile]; 
     } else if ([data length] == 0 && error == nil) { 
      //   [delegate emptyReply]; 
     } else if (error != nil && error.code == NSURLErrorTimedOut) { 
      //   [delegate timedOut]; 
     } else if (error != nil) { 
      //   [delegate downloadError:error]; 
     } 
     [queue release]; 
    }]; 
} 

这会将每个到达的大数据块添加到文件中，如您所愿。 为您的需求自定义请求POST正文，这应该工作。异步:)

Answer 2

好吧，首先检查你的文件的路径，我通常喜欢引用文件路径是这样的：

你需要让你的应用程序的根以这样的方式

NSString* rootPath = NSHomeDirectory(); 

并通过Apple file system guide line

NSString* fullPath = [rootPath stringByAppendingPathComponent:@"subFoldeder/file.extension"]; 

指定关于新数据添加到旧的数据非常快速的解决方案可能是initiali保存在子文件中的一个数据泽你这样可视数据：

NSMutableData *videoData = [[NSMutableData alloc] initWithContentsOfFile:@"filePath"]; 

之后，你可以PROCEDE像你已经史稿您收到的附加数据，并写在最后

做正确的事情完整的文件，以不要使用太多的内存，应该打开一个文件，将其查找到最后并将数据追加到文件中