Nested Json with multipart/form-data in AFNetworking 2.x - ios

Question

I am trying to send nested json with an image from my ios app using AFNetworking library.I am able to send the json data and image successfully but in server the json structure is coming differently.
HTTP request inside my app :-
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
NSDictionary *params = #{#"requestData":#{#"username":#"200OK",#"password":#"password"}};
manager.requestSerializer = [AFJSONRequestSerializer serializer];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
[manager POST:Self_URL
parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
[formData appendPartWithFileData:UIImagePNGRepresentation(image)
name:#"file"
fileName:#"file"
mimeType:#"image/jpeg"];
} success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Response: %#", responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %#", error);
}];
So in my django server I am expecting the params as a dictionary same as params but request.POST is coming as
content_type---> multipart/form-data; boundary=Boundary+247685AB6DF2B3BA
<QueryDict: {'requestData[password]': [u'password'], 'requestData[username]': [u'200OK']}>
How can I send json data so that it will be easy to access from server ?
Anything I am missing or what is going wrong?

Answer 1

constructingBodyWithBlock is overriding your AFJSONRequestSerializer and your dictionary is encoded as form data. There is no way to have two content types (multipart/form-data and application/json) for a request at the same time, so you'll have to do this another way.
One possibility is to encode the JSON as an NSData object and append it to the multipart form along with the image data:
NSError *error = nil;
NSData *paramData = [NSJSONSerialization dataWithJSONObject:params
options:0
error:&error];
[formData appendPartWithFileData:paramData
name:#"params"
filename:#"params"
mimeType:#"application/json"]
You can access the serialized parameters through request.FILES['params']. Despite the mime-type, I doubt that django will automatically parse the JSON data into a dictionary, but you could do that manually with json.loads.

Answer 2

In AFNetworking3.0, you can introduce JSON in a form using the appendPartWithFormData function
[formData appendPartWithFormData:params name:#"params"];
On the server side, you can access the serialized data using json.loads() on the object. Here is a full snippet from some code I wrote:
AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc]initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSMutableURLRequest *request = [[AFHTTPRequestSerializer serializer] multipartFormRequestWithMethod:#"POST"
URLString:requestUrl parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
[formData appendPartWithFormData:[self dictToJson:params] name:#"params"];
[formData appendPartWithFileData:fileData name:fileGeneralName fileName:fileName mimeType:mimeType];
} error:nil];
[[manager uploadTaskWithStreamedRequest:request progress:nil completionHandler:^(NSURLResponse* response, id responseObject, NSError* error) {
[self callCompletionBlock:responseObject withError:error withResponse:response completionHandler:completionBlock];
}] resume];
There's a serialization function in that snippet, which I'll also paste for completion:
+(NSData*)dictToJson:(NSDictionary*)dict {
NSError* error = nil;
return [NSJSONSerialization dataWithJSONObject:dict options:0 error:&error]; }