🐵 Fun(ctional) Http

Possibly the easiest way to start a HTTP server in Node.js.

HTTP server should be as stateless as possible like functions. We should write request handlers in pure funtion. Let's treat return value as responses and use promises to wrap async operations.

Usage

fun-http supports Node >= 4.

As a CLI

1. Install as global package

   $ npm install -g fun-http

2. Define the server, only need to export a function.

   // server.js
   export default async function (req) {
     return 'Hello, World!';
   }

3. Fire the server, and tada~ 🎉

   $ fun-http server.js
   $ curl -i localhost:3000
   
   HTTP/1.1 200 OK
   Date: Sun, 12 Jun 2016 22:12:41 GMT
   Connection: keep-alive
   Content-Length: 13
   
   Hello, World!

As a module

npm install --save fun-http

const FunHttp = require('fun-http').FunHttp;
const app = new FunHttp();

app.use(function (req) {
  return 'Hello, World!';
});

app.listen(3000, () => {
  console.log('server started');
});

Visit localhost:3000 will display "Hello, World!".

You can also return promise in request handlers, the resolved value will become the body of response.

app.use(function (req) {
  return Promise.resolve('Hello, World!');
});

If returned value (or promise resolved value) is not a number or string, it will be parsed into JSON string using JSON.stringify.

Customize Response

fun-http will look for special structure on values returned from request handler to customize response's status and headers.

app.use(function () {
  return {
    status: 404,
    json: {
      reason: 'not found'
    }
  };
});

$ curl -i localhost:3000

HTTP/1.1 404 Not Found
Date: Fri, 10 Jun 2016 00:14:34 GMT
Connection: keep-alive
Content-Length: 22

{"reason":"not found"}

For custom headers:

app.use(function (req) {
  return {
    headers: {
      'x-really-awesome': 'yes!'
    }
  };
});

$ curl -i localhost:3000

HTTP/1.1 200 OK
x-really-awesome: yes!
Date: Fri, 10 Jun 2016 00:14:02 GMT
Connection: keep-alive
Content-Length: 0

You can also force fun-http to return text:

app.use(function (req) {
  return {
    text: 'I just want to tell you...'
  };
});

Middleware

fun-http supports middleware similar to Koa. Calling next will invoke next middleware and return a promise wrapping the return value of that middleware.

app.use(function (req, next) {
  return next()
    .then(name => {
      return {hello: name}; // name === 'World'
    });
});

app.use(function () {
  return 'World';
});

Paire with co, you can make everything cleaner.

const co = require('co');

app.use(co.wrap(function *(req, next) {
  const name = yield next();
  return {hello: name};
}));

app.use(function () {
  return 'World';
});

Or you can even use it with async/await functions:

app.use(async function (req, next) {
  const name = await next();
  return {hello: name};
});

app.use(function () {
  return 'World';
});

Of cause, Node.js doesn't currently support async/await functions, you will need to use transpiler like Babel to transpile the source.

Examples

Check out examples.

TypeScript

Did I tell you fun-http is written using TypeScript?