Waiting for async to be completed

Question

I currently have something like this

   Future<bool>  checkAvailability(String email) async {
        var client = new http.Client();
        var response = await client.get(host);
        bool result;
        if (response.statusCode == 404) {
             result= true;
        }
        else if (response.statusCode == 200) {
              result= false;
        }
        client.close();
        return result;
    }

I am calling the above method from a regular non-aysnc function in this way

void test() {
    checkAvailability(email).then((result){....}
       );
}

The problem with the above code is that its async. From what I understand is that Once checkAvailability is called its launched in a different thread ? and the ui (main) thread continues? Am I correct?

What I would like to do is to have test function wait for the result of checkAvailability. I know I can use await but then the method test will need to be marked as async and when this method is called it will be launched in a different thread. What I want is for the call to checkAvailability be synchronous and I don't mind waiting for a response.

Answer 1

Once checkAvailability is called its launched in a different thread ?

Async execution is not related to threads, async works with an event queue https://webdev.dartlang.org/articles/performance/event-loop

test will need to be marked as async and when this method is called it will be launched in a different thread.

As mentioned before, it won't be another thread. Using async on a test method usually works fine. Why do you try to avoid it?

What I want is for the call to checkAvailability be synchronous and I dont mind waiting for a response.

If you don't care about the result, just don't await it, although this would also cause the calling code to continue before checkAvailability was completed.

What I want is for the call to checkAvailability be synchronous and I dont mind waiting for a response.

There is no way to go back from async execution to sync execution. Once an async call is made, it's completion and the result will always be a Future and needs to be awaited or handled by .then(...).

If you don't care when checkAvailability completes and don't need a result from async calls it makes, then you don't need to await or use then(...). Just call the method and that's it.