floodesh-lib/lib/core.js

core library for floodesh, which contains core request, response and context class, also used for flowesh

'use strict';

const Mof = require('mof')
const Emitter = require('events')
//const merge = require('utils-merge')
const Context = require('./context.js')
const request = require('./request.js')
const response = require('./response.js')

/*
 * depart into 3 stags, onrequest, onresponse, onparsed
 * get task
 * normalize task(could use a middleware)
 * send to other middleware
 *
 * events raised by `Core`: `resquest`, `response`,`process`
 * events subscribed by `Core`: `responding`, `parsed`
 * 
 *
 */

module.exports = class Core extends Emitter{
    constructor() {
	super();
	this.middleware = new Mof();
    }
    
    /**
     * normalize a request options. (keep it simple)
     *
     * @reqopt String or Object of options
     * @api private
     *
     */
    
    // _normalize(reqopt){
    // 	let opt = {
    // 	    gzip:true,
    // 	    encoding:null
    // 	};
	
    // 	if(typeof reqopt === 'string') return (opt.uri=reqopt && opt);
    // 	if(typeof reqopt === 'object') return merge(opt,reqopt);
	
    // 	throw new TypeError("request options must be a string or an object.");
    // }

    /**
     * delegate `use` function of Mof
     **/
    use(fn){
	this.middleware.use(fn);
	return this;
    }

    /**
     * enqueue jobs.
     *
     * @opt `options` of request
     * @theTime callback of bottleneck when it's time
     * 
     * @api protected
     */
    
    enqueue(opt){
	let self = this;
	let ctx = this._createContext(opt);

	process.nextTick(()=>{
	    this.middleware.callback(ctx => self.emit('complete',ctx), (err, ctx) => self.emit('error', err,ctx ) )( ctx );    
	});
	
	return ctx;
    }
    
    /**
     * Initialize a new context.
     *
     * @api private
     */

    _createContext(task){
	const ctx = Context();
	const rq = ctx.request = Object.create(request);
	const rs = ctx.response = Object.create(response);
	ctx.opt = task//this._normalize(task);
	ctx.request.req = ctx.response.res = null;
	rq.ctx = rs.ctx = ctx;
	ctx.app = rq.app = rs.app = this;
	ctx.meta = new Map();
	ctx.dataSet = new Map();
	ctx.tasks = [];
	ctx.resourceList = Object.create(null);
	// ctx.performance = {
	//     enqueueTimestamp:enqueueTimestamp,
	//     bottleneckTimestamp:Date.now(),
	//     requestTimestamp:null,
	//     responseTimestamp:null,
	//     responsemwTimestamp:null,
	//     parsedTimestamp:null
	// };
	return ctx;
    }

    toJSON(){
	return "";
    }
}