iOS中来自JSON的响应不完整

Question

I have a problem with the response received by Json in iOs. I don't know if it is because there is lot of informations concerning the WebService, but the response from Json is not good. I receive an answer, but when I check the string of the data with the variable NSMutableData *d, it is not complete, and in the *response, it can not init with the JSONObjectWithData.

    NSLog(@"Request: %@", bytes);

    NSMutableURLRequest *request = [[NSMutableURLRequest alloc]  initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0];
    NSData *requestData = [NSData dataWithBytes:[bytes UTF8String] length:[bytes length]];

    [request setHTTPMethod:@"POST"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    [request setValue:[NSString stringWithFormat:@"%d", [requestData length]] forHTTPHeaderField:@"Content-Length"];
    [request setHTTPBody: requestData];

    [NSURLConnection connectionWithRequest:request delegate:self];

And the answer :

- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    NSMutableData *d = [NSMutableData data];
    [d appendData:data];
    NSString *a = [[NSString alloc] initWithData:d encoding:NSASCIIStringEncoding];
    NSError *error;
    NSDictionary *response = [NSJSONSerialization JSONObjectWithData:d options:kNilOptions error:&error];
}

Answer 1

The connection:didReceiveData: delegate method is called whenever a chunk of data is received. There is no guarantee that you will receive the complete response in the first call.

The right approach is to collect the data in the connection:didReceiveData: and then process it in connectionDidFinishLoading:

Your code should look something like this:

...
self.receivedData = [NSMutableData data];
...

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [self.receivedData appendData:data]
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSError *error;
    NSDictionary *response = [NSJSONSerialization JSONObjectWithData:self.receivedData options:kNilOptions error:&error];
}