How can i post json string to server

Question

This is json string that I have to post...

{
    \"data\": {
        \"description\": \"\",
        \"current_value\": \"\",
        \"serialno\": \"\",
            


        

Answer 1

Surely this Q us a duplicate, but here's full example code, as one long routine. Just copy and paste.

First set up the JSON...

-(void)sendTestJsonCommand
    {
    NSMutableDictionary *dict = @{
        @"heights":@"4_5_7",
        @"score":@"4",
        @"title":@"Some Title",
        @"textBody":@"Some Long Text",
        @"happy":@"y"
        }.mutableCopy;

    NSError *serr;

    NSData *jsonData = [NSJSONSerialization
        dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&serr];

    if (serr)
        {
        NSLog(@"Error generating json data for send dictionary...");
        NSLog(@"Error (%@), error: %@", dict, serr);
        return;
        }

    NSLog(@"Successfully generated JSON for send dictionary");
    NSLog(@"now sending this dictionary...\n%@\n\n\n", dict);

Next, correctly asynchronously send the command and json to your server...

#define appService [NSURL \
  URLWithString:@"http://www.corp.com/apps/function/user/pass/id/etc"]

    // Create request object
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:appService];

    // Set method, body & content-type
    request.HTTPMethod = @"POST";
    request.HTTPBody = jsonData;
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];

    [request setValue:
        [NSString stringWithFormat:@"%lu",
        (unsigned long)[jsonData length]] forHTTPHeaderField:@"Content-Length"];

    // you would almost certainly use MBProgressHUD at this point
    // to display some sort of spinner or similar action on the UX

Finally, (A) connect correctly using NSURLConnection, and (B) correctly interpret the information which comes back to you from your server.

    [NSURLConnection sendAsynchronousRequest:request
        queue:[NSOperationQueue mainQueue]
        completionHandler:^(NSURLResponse *r, NSData *data, NSError *error)
        {

        if (!data)
            {
            NSLog(@"No data returned from server, error ocurred: %@", error);
            NSString *userErrorText = [NSString stringWithFormat:
               @"Error communicating with server: %@", error.localizedDescription]
            return;
            }

        NSLog(@"got the NSData fine. here it is...\n%@\n", data);
        NSLog(@"next step, deserialising");

        NSError *deserr;
        NSDictionary *responseDict = [NSJSONSerialization
                                      JSONObjectWithData:data
                                      options:kNilOptions
                                      error:&deserr];

        NSLog(@"so, here's the responseDict\n\n\n%@\n\n\n", responseDict);

        // LOOK at that output on your console to learn how to parse it.
        // to get individual values example blah = responseDict[@"fieldName"];
        }];

    }

Hope it saves someone some typing!