-1

检查下面的代码，try/catch 块怎么可能捕获“路由错误”？我的理解是注册到“/”路由的回调在主事件循环上执行，因此指定的 try/catch 块无法捕获异常，因为它不是执行回调的调用堆栈的一部分。

var express = require('express')   ;
var app = express();
var http = require('http');

var mongod = require('mongodb');

var server_conf = new mongod.Server('localhost', 27017, {auto_reconnect:true});

//dummy logger
var logger =  {
    error:function(message, object) {console.log('anything')},
    log:function(message, object) {console.log('anything')},
    debug:function(message, object) {console.log('anything')}}

var db_container = {db: new mongod.Db('test', server_conf,
    {w:1,
        journal:true, native_parser:true, logger: logger})}

app.use(express.bodyParser());
app.use(app.router);

db_container.db.open(function(err, index_info){

    if(err) throw err;
    var testcol = db_container.db.collection('testcol');
    try{
        app.get('/', function(request, res){
           throw new Error("Route Error");
            testcol.insert({hello:"moto"}, function(err,doc){

                if(err){
                    throw err;
                }
                testcol.find({}).toArray(function(err,docs){
                    res.send(docs);
                });
            });

        });
    }
    catch(e){
        res.send("err caught "+ e);
    }
    http.createServer(app).listen(3000, function () {
        console.log('Express server listening on port ' + '3000');
    });
});

一个相关的问题是为什么以下“Crash Me”错误不会导致节点应用程序崩溃。毕竟抛出此错误的所有函数都在主事件循环上运行，并且应该导致未捕获的异常，从而使应用程序崩溃，不是吗？除非本机 mongo 驱动程序捕捉到错误并悄悄地扼杀它......

var express = require('express')   ;
var app = express();
var http = require('http');

var mongod = require('mongodb');

var server_conf = new mongod.Server('localhost', 27017, {auto_reconnect:true});

//dummy logger
var logger =  {
    error:function(message, object) {console.log('anything')},
    log:function(message, object) {console.log('anything')},
    debug:function(message, object) {console.log('anything')}}

var db_container = {db: new mongod.Db('test', server_conf,
    {w:1,
        journal:true, native_parser:true, logger: logger})}

app.use(express.bodyParser());
app.use(app.router);

db_container.db.open(function(err, index_info){

    if(err) throw err;
    var testcol = db_container.db.collection('testcol');
    try{
        app.get('/', function(request, res){

            testcol.insert({hello:"moto"}, function(err,doc){
                throw new Error("Crash Me");

                if(err){
                    throw err;
                }
                testcol.find({}).toArray(function(err,docs){
                    res.send(docs);
                });
            });

        });
    }
    catch(e){
        res.send("err caught "+ e);
    }
    http.createServer(app).listen(3000, function () {
        console.log('Express server listening on port ' + '3000');
    });
});
4

1 回答 1

0

The answer for the first part of the question is here

As for the second part, the question remains open but I believe that it is due to some try catch in the node-mongodb-native silently snuffing the thrown exception.

You can find any associated replies on the node-mongodb-native group here

于 2013-09-03T03:26:06.163 回答