A complete NSURLRequest
represents a complete request by containing a path, query params or body, headers, etc. You can build several of these to represent your several server requests.
NSURLConnection
provides an asynch send (sendAsynchronousRequest:queue:completionHandler:
). A naive way to sequence a series of requests, is to nest the requests in completion blocks as follows...
[NSURLConnection sendAsynchronousRequest:request0 queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (!error) {
[NSURLConnection sendAsynchronousRequest:request1 queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (!error) {
// and so on... yikes, we'll have code in column 1000 pretty soon
But it should be clear that this is a weak idea. You can get the same effect for sequencing an arbitrary number of requests with pretty compact code as follows:
- (void)doManyRequests:(NSArray *)requests withResults:(NSMutableArray *)results completion:(void (^)(void))completion {
if (!requests.count) {
return completion();
}
NSURLRequest *nextRequest = requests[0];
NSArray *remainingRequests = [requests subarrayWithRange:NSMakeRange(1, requests.count-1)];
[NSURLConnection sendAsynchronousRequest:nextRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
[results addObject:data];
[self doManyRequests:remainingRequests withResults:results completion:completion];
}];
}
Now, as you suggested, prepare several requests and place them in an array:
NSURLRequest *request0 = // however you build this for a given user id
NSURLRequest *request1 = // etc.
NSURLRequest *request2 = // etc.
NSArray *requests = @[request0, request1, request2];
NSMutableArray *results = [NSMutableArray array];
[self doManyRequests:requests withResults:results completion:^{
NSLog(@"this will be an array of NSData objects %@", results);
}];