CODEWITHSUNDEEP
objective-cjsonios6afnetworking
rich
rich

Reputation: 2136

AFNetworking JSON Issue

I keep receiving the following error message: 2013-01-22 01:44:43.091 Section3App2[16625:6703] -[__NSCFArray length]: unrecognized selector sent to instance 0x23a48780 after submitting my AFNetworking Request. The idea behind the request is that we are sending a post request to a REST API with a JSON Request Body via POST. I have been fiddling with this all day and can't seem to figure out whats causing the problem.

CODE

NSString *string = @"[{\"code\": \"105N14560\"}]";
    NSString * jsonString = string;
    NSData * data = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError * error = nil;
    id json = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
        [request setHTTPBody:json];
       // [request setValue:[NSString stringWithFormat:@"%d", string.length] forHTTPHeaderField:@"Content-Length"];
        NSLog(@"request body:%@", request.HTTPBody);
       // NSLog(@"json: %@",json);
//    if (!json) {
//        // handle error
//        NSLog(@"fail");
//    }
        AFJSONRequestOperation *operation2 = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
            NSLog(@"JSON: %@", JSON);
        } failure:nil];
        [operation2 start];

That code successfully creates the request body but when it tries to run the block it throws the error and I'm completely stumped. All help would be greatly appreciated.

Upvotes: 0

Views: 1565

Answers (1)

Matt
Matt

Reputation: 1563

Never try to build the JSON string yourself like you're doing in the first line. Use NSJSONSerialization to convert from a JSON-compatible Obj-C data structure (like NSDictionary or NSArray) directly to an NSData object to use as the body of the request. For example:

NSDictionary *JSON = [NSDictionary dictionaryWithObject:@"105N14560" forKey:@"code"];
id JSONData = [NSJSONSerialization dataWithJSONObject:JSON options:0 error:error];

You should use the resulting JSONData object for both the HTTPBody of the request as well as the content-length of the request. Here is a complete example:

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:URL]; // URL = wherever the request should be sent to 

[request setHTTPMethod:@"POST"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"content-type"];

id JSONData = [NSJSONSerialization dataWithJSONObject:JSON options:0 error:error];
if (JSONData) {
    [request setValue:[NSString stringWithFormat:@"%d",[(NSData *)JSONData length]] forHTTPHeaderField:@"content-length"];
    [request setHTTPBody:JSONData];
}

This just creates the request. The rest of it is straightforward using AFNetworking, where using AFJSONRequestOperation you just pass in the request as you've already done.

Upvotes: 3

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