POST JSON data to specific object iOS - ios

Question

I have read several posts on Stack about how to POST data using both XML and JSON however nothing is standing out to me about how to update a selected object.
I am pulling down data from my boss' job tracking API fine, all things are accounted for. However I want to update individual selected object's variables.
Example:
If I have a recipe site API and I am pulling down 100 recipes and displaying the titles in a table. I select a row and it displays a new screen which shows all the details about the recipe with textfields for updating content and a button that will save to the website. How do I update an ingredient on the selected recipe so that it is represented on the website?
Bare in mind I am using my business' API and not Parse.com or another server based database.
I would prefer to use JSON however if there are better solutions using XML I am fine with that.
New Thought
Do I have to replace the entire object when updating?
More Info
Due to using an API, I do not have links directly to a specific object. I get given the block (100 recipes), have to iterate through the block to save each object as NSObject and then sort the newly stored NSObjects how I like to. When I select a row, I am selecting an object that has been sorted and displaying that objects contents. I don't know if this information is helpful or not.
The reason for this extra information is:
When trying to update the Object through the API, how do I know I am updating that specific object and not the entire list of objects?

Answer 1

I think you want to POST data onto the existing fields:
You can try this to POST the data:
NSString *post = [NSString stringWithFormat:#"text_field1=%#",text_field.text];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:#"%lu",(unsigned long)[postData length]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init] ;
[request setURL:[NSURL URLWithString:[NSString stringWithFormat:#"http://your api to recieve the data into the fields"]]];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self];
if(conn) {
NSLog(#"Connection Successful");
} else {
NSLog(#"Connection could not be made");
}
}

Answer 2

I think you can use Mantle on GitHub.
https://github.com/Mantle/Mantle