在node.js中捕获异常 [英] Catch exception in node.js

问题描述

我有一个简单的程序，需要确保可以连接到Redis服务器。我使用node-redis进行连接，需要等待Redis启动。我使用这段代码：

I have a simple program, which needs to make sure I can connect to a Redis server. I use node-redis to connect and need to wait until Redis is started. I use this piece of code:

function initializeRedis(callback) {
    (function createClient(){
        var runner;
        try {
            client = redis.createClient();
        } catch (e) {
            setTimeout(createClient, 1000);
        }
        callback();
    })();
};

initializeRedis(function() {
// Work here
});

这是因为没有try / catch，我从node.js得到了一个异常：

This is because without the try/catch, I got an exception from node.js:

 node.js:134
         throw e; // process.nextTick error, or 'error' event on first tick
         ^ Error: Redis connection to 127.0.0.1:6379 failed - ECONNREFUSED, Connection refused
     at Socket.<anonymous> (/var/www/php-jobs/node_modules/redis/index.js:88:28)
     at Socket.emit (events.js:64:17)
     at Array.<anonymous> (net.js:830:27)
     at EventEmitter._tickCallback (node.js:126:26)

当我启动redis-server（Ubuntu计算机）并启动此脚本时，一切正常。如果我停止redis-server并启动脚本，它不会捕获该异常，但仍会引发该异常。那怎么可能？我有一条try / catch语句！

When I start redis-server (Ubuntu machine) and start this script, everything works fine. If I stop redis-server and start the script, it doesn't catch the exception and still throws this same exception. How is that possible? I have a try/catch statement!

推荐答案

在 client = redis.createClient（）; ，设置错误事件的处理程序：

After client = redis.createClient();, set a handler for the error event:

client.on('error', function(err) {
  // handle async errors here
});

看看堆栈跟踪-您的代码不在其中，所以没有地方尝试/捕获可能会捕获错误。

Have a look at the stack trace - your code isn't in it, so there's no place where a try/catch could catch the error.

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