Add support for request cancellation using AbortController

[melwyn95]

As per #11 added support for request cancellation using the abort controller exposed as CancelToken.

Added test for the same.

@developit I don't know if this the correct way to do this, please let me know what to if I'm wrong

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[melwyn95]

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[developit]

Perfect!!

[n3tr]

Do you think it is better to add support cancelToken API similar to axios cancel token instead of passing abortController signal directly?

Example from axios

const CancelToken = axios.CancelToken;
const source = CancelToken.source();

axios.get('/user/12345', {
  cancelToken: source.token
}).catch(function (thrown) {
  if (axios.isCancel(thrown)) {
    console.log('Request canceled', thrown.message);
  } else {
    // handle error
  }
});

axios.post('/user/12345', {
  name: 'new name'
}, {
  cancelToken: source.token
})

// cancel the request (the message parameter is optional)
source.cancel('Operation canceled by the user.');

We can create a CancelToken function that wrap around the AbortController and return signal as a cancel token, what do you think?

[melwyn-people-interactive]

@developit @n3tr To support the axios API I think we'll have to implement the CancelToken like this

function CancelToken(fn) {
	const ac = new AbortController();
	fn && fn(() => ac.abort());
	return ac.signal;
}
CancelToken.source = () => {
	const ac = new AbortController();
	return {
		token: ac.signal,
		cancel: () => ac.abort()
	};
};

By implementing CancelToken this we can support both the use-cases of cancel token
Use Case 1

const CancelToken = axios.CancelToken;
let cancel;

axios.get('/user/12345', {
  cancelToken: new CancelToken(function executor(c) {
    // An executor function receives a cancel function as a parameter
    cancel = c;
  })
});

// cancel the request
cancel();

Use Case 2

const CancelToken = axios.CancelToken;
const source = CancelToken.source();

axios.get('/user/12345', {
  cancelToken: source.token
}).catch(function (thrown) {
  if (axios.isCancel(thrown)) {
    console.log('Request canceled', thrown.message);
  } else {
    // handle error
  }
});

axios.post('/user/12345', {
  name: 'new name'
}, {
  cancelToken: source.token
})

// cancel the request (the message parameter is optional)
source.cancel('Operation canceled by the user.');

I have tested this locally So if you want I can push this implementation of CancelToken

[developit]

Looks good. I will have to golf it down a lot, but it's nice to see what the API is supposed to be.

[melwyn95]

@developit I pushed the changes, thought a lot about golfing it down, but no breakthrough...

[melwyn95]

Merged master and fixed conflicts

[developit]

Thanks for putting in the effort to keep this moving forward @melwyn95, I'll take another look!

[davie-robertson]

Some great work here - will this be merged into main branch soon?

[donlion]

@developit Any idea when this will be merged? Or is there something we can help with in order to get this ready for merge?

[SergkeiM]

Hi @developit @melwyn95

Any plans to merge this?

[Sreejit7]

@developit @melwyn95 bumping this

[SergkeiM]

@developit @melwyn95 bumping this