测试Express的错误处理

test_express_error_handle.js

/*
 * 创建类似DB服务
 */
var net = require("net");
var server = net.createServer(function(c) {
	console.log('DB-SERVER: client connected');
	c.on('end', function() {
		console.log('DB-SERVER: client disconnected');
	});
	c.on('data', function(chunk) {
		chunk.toString().split("\n").forEach(time => {
			var _tcp_req_id = time.split("|")[0];
			var time = +time.substr(_tcp_req_id.length + 1);
			if (!time) {
				return
			}
			setTimeout(function() {
				c.write(_tcp_req_id + "kill " + time);
			}, time)
		});
	});
});
server.listen(8125, function() {
	console.log('TCP SERVER START!');
});
/*
 * 与DB服务初始化连接，单例模式
 */
var client = net.connect({
	port: 8125
}, function() { //'connect' listener
	console.log('DB-client: connected to server!');

	/*
	 * 初始化WEB服务
	 */
	var express = require("express");
	var app = express();
	app.get('/', function(req, res, next) {
		//根据传进来的时间参数来设定抛出错误的时间
		console.log(req.query)
		var _tcp_req_id = Math.random();
		client.write(_tcp_req_id + "|" + req.query.t + "\n");
		client.once('data', function _cb(chunk) {
			chunk = chunk.toString().split(_tcp_req_id);
			if (chunk.length <= 1) {
				client.once("data", _cb); //重新注册事件
				return
			}
			chunk = chunk[1];
			//直接抛出，client是不守express-app所管制，所以express-app是捕捉不到这个错误的
			var err = new Error(chunk);
			if (req.query.use_next) {
				next(err);
			} else {
				throw err
			}
		});
	});

	var server = app.listen(2333, function() {
		var host = server.address().address;
		var port = server.address().port;

		console.log('Example app listening at http://%s:%s', host, port);
	});

	//Error handling
	app.use(function(err, req, res, next) {
		console.error(err.stack);
		res.status(500).send('Something broke!');
	});

	/*
	 * 请求web服务
	 */
	var http = require("http");
	http.get("http://localhost:2333?t=2000&use_next=true");
	http.get("http://localhost:2333?t=1000&use_next=true");
	http.get("http://localhost:2333?t=4000");
	http.get("http://localhost:2333?t=3000");
});