Question

I am using RestKit 0.9.4. I would like to post a JSON that has a key that needs to be populated from an object’s attribute.
The JSON is as follows:

{
    "types":[ {
        "1" : "value1"
     },
     {  
         "7" : "value2"
     } ]
} 

I have an object with 2 NSString data members named keytype and value respectively .
keytype is the variable that has the values that appear for the key in the nested json above ( “1”, “7” etc above ). mapKeyOfNestedDictionaryToAttribute will probably not work here because the dynamic attribute( to be used as key) is at the inner most level..
Can this be posted using RestKit?

Answer 1

Here’s how you make that structure in an NSDictionary, and then post it as JSON using RestKit. Also, the response then maps to a model.

// make the inner dictionaries (probably would use a for loop for this
NSDictionary *dict1 = [[NSDictionary alloc] initWithObjectsAndKeys:@"value1", @"1", nil];
NSDictionary *dict7 = [[NSDictionary alloc] initWithObjectsAndKeys:@"value2", @"7", nil];
// put them in an array
NSArray *types = [[NSArray alloc] initWithObjects:dict1, dict7, nil];
// now put the array in a dictionary
NSDictionary *finalDict = [[NSDictionary alloc] initWithObjectsAndKeys:types, @"types", nil];

// create a JSON string from your NSDictionary
NSError *error; 
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:finalDict 
                                                   options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                                                     error:&error];
NSString *jsonString = [[NSString alloc] init];
if (!jsonData) {
    NSLog(@"Got an error: %@", error);
} else {
    jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

// make the post using the objectManager if you want to map the response to a model
RKObjectManager* objectManager = [RKObjectManager sharedManager];  
[objectManager loadObjectsAtResourcePath:@"/api/" delegate:self block:^(RKObjectLoader* loader) {
    loader.serializationMIMEType = RKMIMETypeJSON; // We want to send this request as JSON
    loader.objectMapping = [objectManager.mappingProvider objectMappingForClass:[Plan class]];
    loader.resourcePath = @"/api/";
    loader.method = RKRequestMethodPOST;
    loader.params = [RKRequestSerialization serializationWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding] MIMEType:RKMIMETypeJSON];
}];