Doing 1+ async API calls before doing final async API

Question

I have a iOS app where at a given moment I have do 1+ async api calls which needs to be completed before I can send the final async call to my server. What is the best way to do it? e.g.

Start

async call to server 1
async call to server 2
wait for #1 and #2 to get over before async call to server 3

I am using Obj-c

What have you tried? Did you try to search for a way how to achieve this? Many ways. Show some effort and code which doesn't work for you. — zrzka
– zrzka, Commented Jul 20, 2020 at 19:48

skaak · Accepted Answer · 2020-07-21 15:58:59Z

0

As zrzka points out there are many ways to do this. Here is one suggestion.

Use an NSOperationQueue and set async call to server 1 and 2 as dependencies on call to server 3. Here is an outline.

NSOperationQueue * queue = ...

// s1, s2 and s3 are blocks that do your work
NSOperation * server1 = [NSBlockOperation blockOperationWithBlock:s1];
NSOperation * server2 = [NSBlockOperation blockOperationWithBlock:s2];
NSOperation * server3 = [NSBlockOperation blockOperationWithBlock:s3];

[server3 addDependency:server1];
[server3 addDependency:server2];

// Now you can schedule
[queue addOperation:server1];
[queue addOperation:server2];
[queue addOperation:server3];

answered Jul 21, 2020 at 15:58

skaak

3,0281 gold badge10 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Doing 1+ async API calls before doing final async API

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related