node.js - Node : Callback was already called

Question

我知道这里有几个与此相关的重复问题。但是，我不知道如何解决这个问题。我的代码是这样的:

/**
 * DEFINE
 * @connection_kill
 */
apiRoutes.post('/balancer_connection_drop', function(req, res) {
    /* BALANCER - connection kill */
    async.auto({
        decrypt_kill: function(callback, drop, user, stream) {
            /* DROP - decrypt */
            try {
                /* DEFINE - drop */
                var drop = JSON.parse(decrypt(Object.keys(req.body)[0], encryption));

                /* DROP - user & stream */
                callback(null, drop['drop'], drop['user'], drop['stream']);
            } catch(s) {
                /* CLOSE - connection */
                res.end();
            }
        },
        remove_connection: ['decrypt_kill', function(results, callback) {
            /* DROP - balancer || user & stream */
            if ((results[Object.keys(results)[0]])[0] !== 'null') {
                /* DROP - balancer users */
                if (results[Object.keys(results)[0]][0] == 'balancer') {
                    console.log('callback users...');
                    /* DROP - balancer users */
                    pool.query('UPDATE live SET remove=?',[1], function(err, results) {
                        /* DROP - failed */
                        if (err) return callback('Could NOT Drop Users From Live Table!');
                    })
                } else {
                    console.log('callback user...');
                    /* DROP - balancer user */
                    pool.query('UPDATE live SET remove=? WHERE user=? AND stream=?',[1, results[Object.keys(results)[0]][1], results[Object.keys(results)[0]][2]], function(err, results) {
                        /* DROP - failed */
                        if (err) return callback('Could NOT Drop Users From Live Table!');
                    })
                }
            } else {
                console.log('failed to kill data empty...');
                return callback('Balancer Connection Kill Data Empty!');
            }
            console.log('callback...');
            callback();
        }]
    }, function(err, results) {
        /* CHECK - error */
        if (err) return res.send(encrypt(JSON.stringify({'status': 'false'}), encryption));
        /* DROP - success */
        res.send(encrypt(JSON.stringify({'status': 'true'}), encryption));
        /* END - connection */
        res.end();
    })
})

现在，当我调用此 api C 时，会从 Node 收到此错误:

Callback was already called

因此，我放入代码 console.log 来查看两次调用的内容，并在抛出两次调用的错误之前从 console.log 中获取此信息:

callback user...
callback...

所以我发现我犯了一个错误，我调用了它两次，但我不知道如何重写上面的代码以使其在调用回调 user... 时正常工作。我需要去

function(err, results) {

函数并在该函数中将 json 返回到我的服务器 api，但我不知道如何重写它。我尝试使用上面的代码将回调移到函数之外，但回调永远不会被调用。

Answer 1

• 在 pool.query 中处理错误后进行回调

• 问题在于pool.query是异步任务， Node 跳转将异步任务推送到 libuv 后

• 在 pool.query 回调函数之前到达最后一个回调()；

• 在代码到达后调用最后一个回调pool.query回调函数

    apiRoutes.post('/balancer_connection_drop', function(req, res) {

    /* BALANCER - connection kill */
    async.auto({
        decrypt_kill: function(callback, drop, user, stream) {
            /* DROP - decrypt */
            try {
                /* DEFINE - drop */
                var drop = JSON.parse(decrypt(Object.keys(req.body)[0], encryption));

                /* DROP - user & stream */
                callback(null, drop['drop'], drop['user'], drop['stream']);
            } catch(s) {
                /* CLOSE - connection */
                res.end();
            }
        },
        remove_connection: ['decrypt_kill', function(results, callback) {
            /* DROP - balancer || user & stream */
            if ((results[Object.keys(results)[0]])[0] !== 'null') {
                /* DROP - balancer users */
                if (results[Object.keys(results)[0]][0] == 'balancer') {
                    console.log('callback users...');
                    /* DROP - balancer users */
                    pool.query('UPDATE live SET remove=?',[1], function(err, results) {
                        /* DROP - failed */
                        if (err){ return callback('Could NOT Drop Users From Live Table!');}
 
                      return callback();
                    })
                } else {
                    console.log('callback user...');
                    /* DROP - balancer user */
                    pool.query('UPDATE live SET remove=? WHERE user=? AND stream=?',[1, results[Object.keys(results)[0]][1], results[Object.keys(results)[0]][2]], function(err, results) {
                        /* DROP - failed */
                        if (err){ return callback('Could NOT Drop Users From Live Table!');}

                           return callback();
                    })
                }
            } else {
                console.log('failed to kill data empty...');
                return callback('Balancer Connection Kill Data Empty!');
            }
            
        }]
    }, function(err, results) {
        /* CHECK - error */
        if (err) return res.send(encrypt(JSON.stringify({'status': 'false'}), encryption));
        /* DROP - success */
        res.send(encrypt(JSON.stringify({'status': 'true'}), encryption));
        /* END - connection */
        res.end();
    })
})