how to store data in NS-Mutable-data in did-receive-data and than write to file - iphone

Question

I am stuck from 2 days i want to display downlaod progress bar.
I am sending json in post to server and in response server send me video data.
To display progress bar i write some logic code like
In didreceivedata method of ASIhttep i am appending receive data with global NSmutabledata and in request done method i write that global Nsmutalbedata into file.
but file is blank it wont get store into file.
I know ASIHttprequest is old library but everyone suggest me to use AFnetworking but I dont want to change the code because it will take so much time and i have to read documents again.
anybody can help me how can i append data and after downlaod done write that appended data to file??
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

It's better to use asynchronous requests for the task like this. You can use the same ASIHTTPRequest class, but with block approach. Try to write the code similar to this:
-(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];
}];
}
This will append every arrived chunk of your big data into a file as you wanted.
Customize the request POST body for your needs, and this should work. Asynchronously :)

Answer 2

Ok, first check your file path, I usually prefer to refer file path in this way:
you need to get the root of your application in this way:
NSString* rootPath = NSHomeDirectory();
and save the the data in one of the sub folder as specified by Apple file system guide line
NSString* fullPath = [rootPath stringByAppendingPathComponent:#"subFoldeder/file.extension"];
About append new data to old data a very quick solution could be initialize your videoData in this way:
NSMutableData *videoData = [[NSMutableData alloc] initWithContentsOfFile:#"filePath"];
After that you can procede like you are already duing appending data when you receive it, and write the complete file at the end
The correct thing to do, to don't use too much memory should be open a file seek it to the end and append data to the file