Routing

Path and Params	URL Relative Endpoint (URL path)	Functional Endpoint (method/function)
/convert/temperature?unit=c&value=10	/convert/temperature	convert
/convert/length?unit=m&value=2	/convert/length	convert
/translate/english?word=hello	/translate/english	translateEnglish

routing code 💡

We first get the path and then look for endpoint matches to route to the appropriate function or method.

This is the essence of routing: URL endpoint to functional endpoint.

route() {
	const path = this.url.path();
	if (path === '/convert/temperature')
		this.convert(TemperatureConverter);
	else if (path === '/convert/length')
		this.convert(LengthConverter);
	else if (path === '/translate/english')
		this.translateEnglish();
	else
		log(`URL Path not handled: ${path}`);
}

Functional Endpoint

We are now in a functional endpoint "convert".

We grab the query params unit and value, and then construct a model, and serve the results.

convert(converterClass) {
	const
		query = this.url.query(),
		unit = query.unit,
		value = query.value;
	if (!this.validateParam('unit', unit) || !this.validateParam('value', value))
		return;
	const converter = new converterClass(unit, value);
	this.serveConversionResults(converter.getResults());
}

serve

The "serve" method logic is familiar -- writing the results as HTML to the reponse.

The result is a collection of value-unit pairs.

serveConversionResults(arrayResults) {
	//serve result to client/consumer
	const res = this.response;
	res.writeHead(statusCodes.OK, htmlContentType);
	//result is an array
	for (let pair of arrayResults)
		res.write(`${pair.value} ${pair.unit}` + br);
	res.end();
}

Output

Web browser client showing results

2 m
6.56168 ft
2000 mm
200 cm
0.002 km
78.74016 in
0.00124 mi
2.18723 yd

Source Code

Here is the example project source code.

The project will require an npm init, and then npm installs of two modules: "http-status-codes" and "url-wrapper".