Call another address with AJAX() from the server

Total.js 5 · total5@0.0.19 httprequestsajax Executed against Total.js 5

AJAX('METHOD url', [data], [callback]) makes an HTTP request and gives you the parsed answer. It is the short form of REQUEST() for APIs that talk JSON: the same call that jComponent has in the browser, so the code of the page and of the server look alike.

The address starts with an optional method: AJAX('POST [https://example.com/api/'](https://example.com/api/'), data). Without a method it is a GET.
data, when given, is sent as a JSON body. The request carries the header x-requested-with: XMLHttpRequest, so on the other side $.xhr is true.
The answer is parsed by its content type: JSON becomes an object, application/x-www-form-urlencoded becomes an object, anything else arrives as text.
When the status is 400 or more, the promise is rejected (or the callback gets the error first) with the parsed body of the answer as the error. A callback is called as callback(err, value, response).
Without a callback it returns a promise.

For XML answers use REQUEST() and parse the body yourself: AJAX() is made for JSON and text answers.

The example calls routes of the same application, whose address $.hostname('/') gives, so that it needs no other server.

controllers/calls.js

exports.install = function() {
	ROUTE('GET /api/hello/', hello);
	ROUTE('POST /api/echo/', echo);
	ROUTE('GET /api/text/', text);
	ROUTE('GET /api/xml/', xml);
	ROUTE('GET /api/fail/', fail);
	ROUTE('GET /calls/', calls);
};

function hello($) {
	$.json({ hello: 'world', xhr: $.xhr });
}

function echo($) {
	$.json({ received: $.body, xhr: $.xhr });
}

function text($) {
	$.plain('plain text');
}

function xml($) {
	$.xml('<a><b>1</b></a>');
}

function fail($) {
	$.invalid('It is wrong');
}

async function calls($) {

	const base = $.hostname('/');
	const out = {};

	out.hello = await AJAX('GET ' + base + 'api/hello/');
	out.nomethod = await AJAX(base + 'api/hello/');
	out.echo = await AJAX('POST ' + base + 'api/echo/', { a: 1 });
	out.text = await AJAX(base + 'api/text/');

	try {
		await AJAX(base + 'api/fail/');
	} catch (err) {
		out.error = err.message || err;
	}

	out.callback = await new Promise(resolve => AJAX(base + 'api/hello/', (err, value, response) => resolve({ err: err, hello: value.hello, status: response.status })));

	out.xml = await Promise.race([
		AJAX(base + 'api/xml/').then(() => 'answered', () => 'rejected'),
		new Promise(resolve => setTimeout(() => resolve('never answered'), 1000))
	]);

	$.json(out);
}