Objective C Update RESTful Webservice - objective-c

Question

I have a web service that allows me to update records on in our database.
The columns in the table are as follows:
allowsActions
assetID
inventoryObjectID
objectDescription
quantity
retired
serialNumber
action
I'm using the following to GET data from the webservice.
NSString *urlString = [NSString stringWithFormat:#"%#", inventoryAndActionsWebservice];
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:#"GET"];
Then shoving into a dictionary like so:
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError)
{
if (data.length > 0 && connectionError == nil)
{
NSLog(#"WE HAS THE DATAS");
NSDictionary *inventory = [NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];
// Then storing the values in CoreData here
}
}
What would be the syntax for updating the webservice? It expects an object in the body of the service call (POST).

Answer 1

NSMutableURLRequest let's you setHTTPBody: and setHTTPMethod:.#"POST"is the way to do a post. Most services need to know the body length and encoding set in headers. (seeaddValue:forHTTPHeaderField:`) for that.
The only reason this topic is tricky is because the developer is forced to grapple with two problems at once: what constitutes a valid request for my server, and (2) how do I form that request with iOS? Part (2) is actually pretty easy once you get a valid request.
The best way to proceed is to get an example working using curl (or something equivalent). Then move on to producing that request in iOS. If you have trouble, ask a question here of the form: "I know my server needs X, here's my code to produce X, but I'm getting this error Y".

Answer 2

So the syntax that I was looking for was ultimately this:
NSString *jSONString = [NSString stringWithFormat:#"{\"MediaInventoryObjectsId\":%d,\"AssetId\":%d,\"Quantity\":%d,\"SerialNumber\":\"%#\",\"Description\":\"%#\",\"AllowActions\":%d,\"Retired\":%d}",inventoryObjectId, assetID, quantity, serialNumber, description, allowActions, retired];
// Convert jSON string to data
NSData *putData = [jSONString dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
// Instantiate a url request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
// Set the request url format
[request setURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#/%d", inventoryAndActionsWebservice, inventoryObjectId]]];
[request setHTTPMethod:#"PUT"];
[request setHTTPBody:putData];
[request setValue:#"application/json" forHTTPHeaderField:#"content-type"];
// Send data to the webservice
NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];