http - module to monitor an http request from Node.js

http-monitor.js

var http = require("http");
var log = require("./log");
var cache = require("./cache");
var getRequestTime = require("./request-time");

var requestList = []; //request buffer

//register a Node.js http request then monitor the request
//monitor means to check if the request is in process, a duplicate or it finished
function registerRequest(url){
	var start = new Date();
	var reqID = setInterval(function(){ //monitor request status and time
		log("IN PROGRESS", url, "time:", getRequestTime(start, new Date()));
	}, 1000);
	log("BEGIN", url); //request just started
	return function(){ //http request ended
		clearInterval(reqID);
		log("FINISHED", url, "time:", getRequestTime(start, new Date()));
	};
}

function ingestResponse(serviceResponse, unregisterRequest, url, httpRes){ //consume the server http response
	serviceResponse.setEncoding('utf8');
	var data = "";
	serviceResponse.on("data", function(chunk) {
		data += chunk;			
	});

	serviceResponse.on("end", function(){
		try{
			unregisterRequest();
			httpRes.json(serviceResponse.statusCode, JSON.parse(data));
		}catch(e){
			log("ERROR", e, url);
		}
	});

}

function doRequest(url, httpRes){ //Node.js http request
	log("GET", url);
	var unregisterRequest = registerRequest(url);
	http.get(url, function(serviceResponse){ 
		ingestResponse(serviceResponse, unregisterRequest, url, httpRes);
	}).on("error", function(e){
		log("ERROR", url, e);
		unregisterRequest();
		httpRes.json(500, e);
	});
}

exports = module.exports = {

	getClients: function(httpRes){ //web service request
		var url = "clients";
		doRequest(url, httpRes);
	},

	getSales: function(httpRes){ //web service request
		var url = "sales?client="+req.client;
		doRequest(url, httpRes);
	}
}