API – How to Optimize Calls to Multiple APIs at Once and Return as One Set

apiasyncweb services

I have a web app that searches across 2 APIs right now. I have my own Restful web service that I call, and it does all the work on the backend to asynchronously call the 2 APIs and concatenate them into one result set for my web app to use.

I want to scale this out and add as many other APIs as I can (currently looking at about 10 more). But as I add APIs, the call to my service gets (potentially) slower and more complex. How do I handle one API not responding … and other issues that arise?

What would be the best way to approach this? Should I create a service call for each API, that way each one is independent and not coupled to all the other calls? Is there a way on the backend to handle the multiple API calls without all the extra complexity it adds?

If I go the route of a service call per API, now my client code gets more complex (and I have a lot of clients)? And it's more work for the client, and since I have mobile apps, it will cost the client more data usage.

If I go one service call, is there a way to set up some sort of connection so I can return data as I get it, in case one service call hangs?

Best Answer

In systems like this, you always have to consider that as far as your code is powerful, at least a call will be delayed, and if your system is successful, that event will happen hundreds of times making your system slow, then maybe unstable.

I do not know the nature of the integration, maybe game providers, maybe social networks or anything else. But if your application is not academic, and it represents a real business requirements (in production) I think this is part of the things to do:

Before code

  1. if possible, all systems that are integrated, they must be aware of the timeouts that are demanded from you (anticipating this from a contractual point of view, it is a good idea mostly because no one guarantees 100% of up-time. It's myth).
  2. if point 1 is not possible, be objective and consider what we are willing to make our customers wait in front of the monitor (45 seconds, 10, 5, 2?). Found the value, we know how to set up the rest.
  3. Should be considered a constant calls/sub-calls prifile and logging;
  4. Should be planned for the possibility of suspending one or more services from the configuration (and not from code);

Technique

As for the technique, I think it is convenient to create a semaphore.

N functions will be called, the callback of each sub-function will be considered only if time set for each integration are respected.

So,

  1. A call is made to the main function,
  2. This considers what services are enabled to be contacted,
  3. The callback functions are configured,
  4. The sub-functions are called,
  5. While making calls, and while the general timer has not expired, all callbacks are considered to be unified in the response of the main function.
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