How to synchronize two NSURLSessionDataTasks?

Question

I don't know how to synchronize NSURLSessionDataTask.

How do I synchronize these two sessions in syncInfo1Info2:

- (void) syncInfo1Info2
{
  //How do I sync???
}

- (void) getSomeInfo1
{
NSString *stringToUrl = [[NSString alloc]initWithFormat:@"url"];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[stringToUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
NSURLSessionDataTask *task =[session dataTaskWithRequest: request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){
    //Some code...

        }];
[task resume];
}

- (void) getSomeInfo2
{
NSString *stringToUrl = [[NSString alloc]initWithFormat:@"url"];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[stringToUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
NSURLSessionDataTask *task =[session dataTaskWithRequest: request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){
   //Some code...

}];
[task resume];
}

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score 3 · Answer 1 · answered Dec 12 '14 at 13:51

Like this:

dispatch_group_t group = dispatch_group_create();

- (void) syncInfo1Info2
{
  [self getSomeInfo1];
  [self getSomeInfo2];
  dispatch_group_notify(group, dispatch_get_main_queue(), ^{
     //both tasks have been processed
  });
}

- (void) getSomeInfo1
{
    dispatch_group_enter(group);
    NSString *stringToUrl = [[NSString alloc]initWithFormat:@"url"];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
    NSMutableURLRequest *requestRu = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[stringToUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
    NSURLSessionDataTask *task =[session dataTaskWithRequest: requestRu completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){
        NSError *err;
        dispatch_group_leave(group);
        }];
    [task resume];
}

- (void) getSomeInfo2
{
    dispatch_group_enter(group);
    NSString *stringToUrl = [[NSString alloc]initWithFormat:@"url"];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
    NSMutableURLRequest *requestRu = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[stringToUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
    NSURLSessionDataTask *task =[session dataTaskWithRequest: requestRu completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){
        NSError *err;
        dispatch_group_leave(group);
    }];
    [task resume];
}

score 0 · Answer 2 · edited May 23 '17 at 12:09

Simple way you can use NSOperationQueue to add dependencies between operations

eg.

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

NSBlockOperation *downloadOperation1 = [[NSBlockOperation alloc] init];
 __weak NSBlockOperation *weakOperation1 = downloadOperation1;

[weakOperation1 addExecutionBlock:^{
    [self getSomeInfo1];
}];


NSBlockOperation *downloadOperation2 = [[NSBlockOperation alloc] init];
__weak NSBlockOperation *weakOperation2 = downloadOperation2;

[weakOperation2 addExecutionBlock:^{
    [self getSomeInfo2];
}];

[downloadOperation2  addDependency:downloadOperation1];
[operationQueue addOperation:downloadOperation1];
[operationQueue addOperation:downloadOperation2];

or use the method given in this link

create NSURLSession singleton in class that has its HTTPMaximumConnectionsPerHost property set to 1:

+ (NSURLSession *)session
{
    static NSURLSession *session = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{

        NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

        [configuration setHTTPMaximumConnectionsPerHost:1];

        session = [NSURLSession sessionWithConfiguration:configuration];

    });
    return session;
}

and Then use

NSURLSessionDataTask *dataTask = 
[[[self class] session] dataTaskWithURL:url 
                          completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
}
[dataTask resume]

Ashish · Answer 3 · 2018-09-23T04:23:21.073

0

We can put the api gunc in a class and creaye a shared instance on it and in view controller class we can just make call with the class instance like

ApiClient.shared.api1() ApiClient.shared.api2()

Since we have a shared instance api calls will be synchronized

edited Sep 23 '18 at 04:23

answered Feb 06 '17 at 11:26

Ashish

204
1
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How to synchronize two NSURLSessionDataTasks?

3 Answers3