NSURLSession didReceiveData called continuously for same request with same response

Question

krsunmoon OP

Created Sep ’17

Replies 2

Boosts 0

Views 1.4k

Participants 2

Hello Everyone,

I am facing a strange problem with NSURLSession which i never faced before.

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
    NSMutableData *responseData = self.responsesData[@(dataTask.taskIdentifier)];
     if (!responseData) {
        responseData = [NSMutableData dataWithData:data];
        self.responsesData[@(dataTask.taskIdentifier)] = responseData;
    } else {
        [responseData appendData:data];
    }
 }

The above delegate method is called repeatedly so that the below delegate method is not called and app is hanged because of that.

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(nullable NSError *)error { }

Methods used to create NSURLSessionDataTask are given below.

-(void)fetchDataAboveiOS7:(NSMutableURLRequest*)request :(void(^)(NSURLResponse *response, NSData *data, NSError *error))completionHandler 
{ 
__block NSURLSessionDataTask *task;
 task = [[self getSessionConfiguration] dataTaskWithRequest:request];
__block NSMutableArray *networkError;

if (!networkError) { 
networkError = [[NSMutableArray alloc]init]; 
}

[task setTaskDescription:[request allHTTPHeaderFields][kTempId]]; 
[task resume]; 
}

-(NSURLSession *)getSessionConfiguration { 
if (self.session) { 
return self.session; 
} 
NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration]; 
config.timeoutIntervalForRequest = kRequestTimeOut; config.allowsCellularAccess = YES; 
config.HTTPMaximumConnectionsPerHost = kMaximumConnectionPerHost; 
config.requestCachePolicy = NSURLRequestReloadIgnoringLocalCacheData; 
self.session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]]; 
return self.session; 
}

Additional Code which used for creating NSURLRequest and this object is sent to fetchDataAboveiOS7

NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:_url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:timeOutInterval]; 
/method*/ 
[request setHTTPMethod:method]; 
if (self.sessionCookie != nil) 
{ 
[request setValue:self.sessionCookie forHTTPHeaderField:kCookie]; 
} 
NSMutableDictionary *headerDict = [[NSMutableDictionary alloc] init]; 
[headerDict setValue:@"application/json;charset=UTF-8" forKey:@"Accept"]; 
[headerDict setValue:@"application/json;charset=UTF-8" forKey:@"Content-Type"]; 
for (NSString *key in [headerDict allKeys]) 
{ 
[request addValue:[headerDict valueForKey:key] forHTTPHeaderField:key]; 
} 
if (bodyDict) { 
[request setHTTPBody:[NSJSONSerialization dataWithJSONObject:bodyDict options:kNilOptions error:&error]]; 
} 
[self fetchDataAboveiOS7:request :^(NSURLResponse *response, NSData *data, NSError *error) { 
}];

Thanks in Advance..

Boost

Answer 1

DTS Engineer OP

Apple

Sep ’17

It’s expected that ‘didReceiveData’ will be called multiple times, as you’re well aware based on the code that you have in your implementation. So, the question isn’t “Why is this called multiple times?” but rather “Why is this called multiple times with the same data?” And the first step there is to rule out the possibility that the server is sending you multiple copies of the same data. If you enable CFNetwork diagnostic logging (per QA1887 CFNetwork Diagnostic Logging), you do see multiple copies of the data come up from ‘below’?

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Apple Developer Relations, Developer Technical Support, Core OS/Hardware

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0

Answer 2

krsunmoon OP

Sep ’17

Thanks for the reply.

I enabled the CFNetwork diagnostic log in my Project. I can see the multiple copies of the data coming in the log as well. below is the snapshot of the log. Can u tell me what's going wrong?

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406814] 19:05:22.937 {

{ fd: 21, local 192.168.2.49:50082 => peer 192.168.2.200:443 } SSL-READ 254: (null)

SSL-READ (21) | < data [ 144 ] bytes {

SSL-READ (21) | < 00000000: 7b22 7265 7370 6f6e 7365 223a 5b7b 2272 {"response":[{"r

SSL-READ (21) | < 00000010: 6571 7565 7374 223a 7b22 6f70 6572 6174 equest":{"operat

SSL-READ (21) | < 00000020: 696f 6e22 3a22 6372 6561 7465 227d 2c22 ion":"create"},"

SSL-READ (21) | < 00000030: 6461 7461 223a 7b22 7665 7222 3a31 2c22 data":{"ver":1,"

SSL-READ (21) | < 00000040: 6373 7622 3a22 3022 2c22 7072 6f70 6572 csv":"0","proper

SSL-READ (21) | < 00000050: 7479 5479 7065 223a 2274 7365 7422 2c22 tyType":"tset","

SSL-READ (21) | < 00000060: 6e61 6d65 223a 2248 6f6d 6520 222c 226e name":"Home ","n

SSL-READ (21) | < 00000070: 7622 3a22 3022 2c22 7072 6f6a 6563 7422 v":"0","project"

SSL-READ (21) | < 00000080: 3a22 7465 7374 222c 2269 6422 3a22 683a :"test","id":"h:

SSL-READ (21) | < }

} [3:406814]

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406818] 19:05:22.938 { touchConnection: (null)

Loader: <CFMutableURLRequest 0x1781b4820 [0x1b1432bb8]> {url = https://192.168.2.200:443/IHAMobile1?requestType=updateConfiguration, cs = 0x0}

Timeout Interval: 10.000 seconds

} [3:406818]

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406819] 19:05:22.938 {

{ fd: 21, local 192.168.2.49:50082 => peer 192.168.2.200:443 } SSL-READ continuation: (null)

SSL-READ (21) | < data [ 110 ] bytes {SSL-READ (21) | < 00000000: 6135 6637 222c 2274 7970 6522 3a22 7072 a5f7","type":"pr

SSL-READ (21) | < 00000010: 6f70 6572 7479 222c 2270 726f 7065 7274 operty","propert

SSL-READ (21) | < 00000020: 7949 6422 3a22 7465 732d 7473 652d 3030 yId":"tes-tse-00

SSL-READ (21) | < 00000030: 3236 2d41 3430 3622 2c22 7369 6422 3a34 26-A406","sid":4

SSL-READ (21) | < 00000040: 3234 3837 7d2c 2273 7461 7475 7322 3a22 2487},"status":"

SSL-READ (21) | < 00000050: 7375 6363 6573 7322 7d5d 2c22 7374 6174 success"}],"stat

SSL-READ (21) | < 00000060: 7573 223a 2273 7563 6365 7373 227d us":"success"}

SSL-READ (21) | < }

} [3:406819]

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406820] 19:05:22.938 {

Load Data: (null)

Loader: <CFMutableURLRequest 0x1781b4820 [0x1b1432bb8]> {url = https://192.168.2.200:443/IHAMobile1?requestType=updateConfiguration, cs = 0x0}

Length: 254

Original Length: 254

} [3:406820]

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406821] 19:05:22.939 {

touchConnection: (null)

Loader: <CFMutableURLRequest 0x1781b4820 [0x1b1432bb8]> {url = https://192.168.2.200:443/IHAMobile1?requestType=updateConfiguration, cs = 0x0}

Timeout Interval: 10.000 seconds

} [3:406821]

Sep 15 19:05:22 iPad IHA(CFNetwork)[249] <Notice>: CFNetwork Diagnostics [3:406822] 19:05:22.939 {