RestKit - how to queue resource loading? - iphone

Question

So, here is my question.
What I want to do, is to queue resources loading; so that every resource request load is done one at a time, and one after the other (controlling the order I receive those resources).
What would be the correct, and cleaner way to complete such a behaviour?

Answer 1

Ok, I think I got it.
Every RKObjectLoader is a subclass of a RKRequest object. So it may be associated to a customized RKRequestQueue.
Let that RKRequestQueue be configured so that only 1 element can be treated at a time we could achieve the ordering. By setting its concurrency to 1.
I have the pseudo-code :
Create a RKRequestQueue and define its concurrency to 1.
Mark it as suspended, so that it will wait load until I'm done with queueing my resource loading requests.
Loop over my resource loading requests and add them in the order I want them to be executed.
We start with a lazy loading of the request queue
- (RKRequestQueue *)mainDownloadRequestQueue {
if (!_mainDownloadRequestQueue) {
// Creating the request queue
RKRequestQueue * queue = [RKRequestQueue requestQueue];
//queue.delegate = self;
queue.concurrentRequestsLimit = 1;
queue.showsNetworkActivityIndicatorWhenBusy = YES;
// Start processing!
[queue start];
_mainDownloadRequestQueue = [queue retain];
}
return _mainDownloadRequestQueue;
}
And the main methods could/should look like this, we set the queue in the blocks, just before it is checked by RestKit that a queue is available for handling download.
- (void)setUpMainQueue {
// We lock the download queue so that, no download will start until, we want it
[[self mainDownloadRequestQueue] setSuspended:YES];
// Fill up the queue
[self fillQueueWithMandatoryDownloads];
// No, let's start and wait for data to be there
[[self mainDownloadRequestQueue] setSuspended:NO];
}
- (void)fillQueueWithMandatoryDownloads {
// Add the first request
[self addLanguagesRequest];
// Add another request
[self addLanguagesRequest];
// … Add any other request
}
- (void)addLanguagesRequest {
// Load the object model via RestKit
RKObjectManager *objectManager = [RKObjectManager sharedManager];
objectManager.client.baseURL = [RKURL URLWithString:kFoundationHost];
__unsafe_unretained OMResourceLoader * wSelf = self;
[objectManager loadObjectsAtResourcePath:#"/sources/api/languages" usingBlock:^(RKObjectLoader * loader) {
// Set the queue there, this is the one defined
loader.queue = [wSelf mainDownloadRequestQueue];
// Do other configuration or behaviour for that
loader.onDidLoadObjects = ^(NSArray *objects) {
[[OMLogManager sharedLogManager] log:[objects description] logLevelParam:OM_LOG_LEVEL_INFO exceptionParam:nil errorParam:nil];
};
}];
}
- (void)addCategoriesRequest {
// Load the object model via RestKit
RKObjectManager *objectManager = [RKObjectManager sharedManager];
objectManager.client.baseURL = [RKURL URLWithString:kFoundationHost];
__unsafe_unretained OMResourceLoader * wSelf = self;
[objectManager loadObjectsAtResourcePath:#"/sources/api/categories" usingBlock:^(RKObjectLoader * loader) {
// Set the queue
loader.queue = [wSelf mainDownloadRequestQueue];
loader.onDidFailLoadWithError = ^(NSError * error) {
[[OMLogManager sharedLogManager] log:#"Categories loading error" logLevelParam:OM_LOG_LEVEL_ERROR exceptionParam:nil errorParam:error];
};
loader.onDidFailWithError = ^(NSError * error) {
[[OMLogManager sharedLogManager] log:#"Categories loading error" logLevelParam:OM_LOG_LEVEL_ERROR exceptionParam:nil errorParam:error];
};
loader.onDidLoadResponse = ^(RKResponse *response) {
[[OMLogManager sharedLogManager] log:[[response bodyAsString] description] logLevelParam:OM_LOG_LEVEL_INFO exceptionParam:nil errorParam:nil];
};
loader.onDidLoadObjects = ^(NSArray *objects) {
[[OMLogManager sharedLogManager] log:[objects description] logLevelParam:OM_LOG_LEVEL_INFO exceptionParam:nil errorParam:nil];
};
}];
}