Question

I am using the great RestKit Framework for an iPhone Application.
I have got a method, where I send requests to a webservice. Sometimes four or more requests per 30 seconds.

My sendMethod looks like:

 - (void) sendLocation {

NSString *username = [userDefaults objectForKey:kUsernameKey];    
NSString *password = [userDefaults objectForKey:kPasswordKey];
NSString *instance = [userDefaults objectForKey:kInstanceKey];
NSString *locationname = self.location.locationname;

NSString *url = [[NSString alloc] initWithFormat:@"http://www.someadress.com/%@", instance];

RKClient *client = [RKClient clientWithBaseURL:url username:username password:password];

// Building my JsonObject
NSDictionary *locationDictionary = [NSDictionary dictionaryWithObjectsAndKeys: username, @"username", locationname, @"locationname", nil];
NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjectsAndKeys:locationDictionary, @"location", nil];

NSString *JSON = [jsonDictionary JSONRepresentation];
RKParams *params = [RKRequestSerialization serializationWithData:[JSON dataUsingEncoding:NSUTF8StringEncoding]MIMEType:RKMIMETypeJSON]; 

[client  post:@"/locations" params:params delegate:self];
 }

Sometimes (especially when sending more requests after another) the value of the count property of the RKRequestQueue Object is > 1.
When my application enters background and then enters foreground the requests in the queue (when foreground is entered) are sent to my Webservice and the delegate

- (void)request:(RKRequest*)request didLoadResponse:(RKResponse*)response {)

for all requests will be called.

So the question is:
Why doesnt RestKit send some requests immediately (my Webservice doesnt receive anything while a request is stored in the queue)???

Does anyone know a solution or had/has the same problem?

Answer 1

I noticed this line where you create the RKClient:

RKClient *client = [RKClient clientWithBaseURL:url username:username password:password];

This basically creates new instance each time sendLocation method is called – are you sure this is your desired behavior? If the url, username and password does not change, you can access previously created client by calling [RKClient sharedClient]. In your current approach, new request queue is created for each new client.

Now back to the point. Take a look on this property of the RKRequestQueue:

/**
* The number of concurrent requests supported by this queue
* Defaults to 5
*/
@property (nonatomic) NSUInteger concurrentRequestsLimit;

As you can see this defaults to 5, so if you have more than that in any of your queues they will wait until the ongoing requests are processed. You also mentioned that the requests stack up when the application is moved to background, and then when it enters the foreground all of them are dispatched. You can control how your requests behave like this:

- (void)backgroundUpload {
    RKRequest* request = [[RKClient sharedClient] post:@"somewhere" delegate:self];
    request.backgroundPolicy = RKRequestBackgroundPolicyNone; // Take no action with regard to backgrounding
    request.backgroundPolicy = RKRequestBackgroundPolicyCancel; // If the app switches to the background, cancel the request
    request.backgroundPolicy = RKRequestBackgroundPolicyContinue; // Continue the request in the background
    request.backgroundPolicy = RKRequestBackgroundPolicyRequeue; // Cancel the request and place it back on the queue for next activation
}

I have found this solution here. Scroll down to Background Upload/Download section.