NSURLSession and NSOperationQueue working together
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Correct the spelling of CocoaPods in README
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README.md

TRVSURLSessionOperation

By @travisjeffery.

NSURLSession and NSOperationQueue working together

TRVSURLSessionOperation is an NSOperation subclass that wraps NSURLSessionTask so you can use them in a NSOperationQueue.

With this you can:

  • Schedule network requests (i.e. run request A then request B, and give requests priority)
  • Limit the number of concurrent network requests (e.g. have 5 network requests running at any given time)
  • Control these network operations the same as other NSOperation objects (e.g. you have an NSOperation that creates an image, then an TRVSURLSessionOperation that uploads that image to a web service)

Usage

NSOperationQueue *queue = [[NSOperationQueue alloc] init];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://twitter.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

Run a request on the completion of another, specific request

For example, you have an initial request to log a user in or fetch their settings, and you want subsequent requests to wait for that initial request to finish and then they run.

NSOperationQueue *queue = [[NSOperationQueue alloc] init];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

TRVSURLSessionOperation *settingsOperation = [[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"..."] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }];

TRVSURLSessionOperation *anotherOperation = [[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"..."] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }];

// get some settings for your app from your server, and queue subsequent requests that depend on those settings.
[anotherOperation addDependency:settingsOperation];

[queue addOperations:@[ loginOperation, settingsOperation ] waitUntilAllOperationsAreFinished:NO];

Pause and resume/suspend requests from executing

NSOperationQueue *queue = [[NSOperation alloc] init];
queue.suspended = YES;

// these request/operations won't run
[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://twitter.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://github.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

queue.suspended = NO;
// until now

Limit the number of concurrent requests

NSOperationQueue *queue = [[NSOperationQueue alloc] init];
queue.maxConcurrentOperationCount = 1; // only one request will run at once

NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://twitter.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://github.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

Wait until all requests are finished

NSOperationQueue *queue = [[NSOperationQueue alloc] init];

NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://twitter.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

[queue addOperation:[[TRVSURLSessionOperation alloc] initWithSession:session request:[NSURLRequest requestWithURL:@"https://github.com/travisjeffery"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { ... }]];

[queue waitUntilAllOperationsAreFinished];

NSLog(@"All requests are done!");

Install

Use CocoaPods, and put the following in your Podfile:

pod 'TRVSURLSessionOperation', '~> 0.0.1'

Or manually drag the TRVSURLSessionOperation folder into your Xcode project.