use-server/dist/index.js

A light-weight, promise-based and middleware-driven web framework

'use strict';

const Emitter = require('events');
const http = require('http');
const onFinished = require('on-finished');
const compose = require('use-compose');
const bindExpress = require('./express');

const statuses = http.STATUS_CODES;

class Application extends Emitter {

  // babel 6 bug on no constructor, see https://github.com/babel/babel/issues/4254
  // after babel fix it, remove this constructor
  constructor() {
    var _this;

    //eslint-disable-line
    _this = super();
    this._middlewares = [];

    this.use = function () {
      for (var _len = arguments.length, middlewares = Array(_len), _key = 0; _key < _len; _key++) {
        middlewares[_key] = arguments[_key];
      }

      for (const middleware of middlewares) {
        if (typeof middleware !== 'function') throw new TypeError('use() only accept function');
        _this._middlewares.push(middleware);
      }
      return _this;
    };

    this.listener = () => {
      const stack = compose(this._middlewares);

      // forward the request to new url
      // usage: return req.forward('/new/path')
      const forward = (req, resp, newUrl) => {
        req.originalUrl = req.url;
        req.url = newUrl;
        return stack.call(this, req, resp);
      };

      return (req, resp) => {
        req.app = this;
        req.basePath = ''; // compatible with use-router

        req.forward = forward.bind(this, req, resp);

        const onerror = this._onerror.bind(this, resp);
        onFinished(resp, onerror);

        return stack.call(this, req, resp).then(() => {
          if (resp.headersSent) return resp.end();

          resp.statusCode = 404;
          return resp.end(statuses[404]);
        }).catch(onerror);
      };
    };

    this.listen = function () {
      const server = http.createServer(_this.listener());
      return server.listen.apply(server, arguments);
    };

    this._onerror = (resp, err) => {
      if (!err) return;

      if (this.listenerCount('error') <= 0) {
        console.error('Caught an error in use-server: %s', err.stack || err.toString());
      } else {
        this.emit('error', err);
      }

      if (resp.headersSent) return resp.end();

      let statusCode = parseInt(err.statusCode || err.status || err.code, 10);
      if (!statusCode || typeof statusCode !== 'number' || statusCode >= 1000 || statusCode < 400) {
        statusCode = 500;
      }

      resp.statusCode = statusCode;
      resp.end(err.message || statuses[statusCode] || 'Unknown Error');
    };
  }

  // used as `http.createServer(app.listerner())`
}

module.exports = () => {
  const app = new Application();
  bindExpress(app);
  return app;
};