Looking for solutions in Node.js

Question

I am looking for a solution for a problem in Node.js. Please help !

I have a router "find user", if user is existed in db continue do taskFunc(), else response error. But, my taskFunc() must take many time to complete, because each 30 seconds it will do a task.

I want to after check user exist, must response to client immediately, taskFunc() just run on server, if has error then throw.

router.post('/router1, function(req, res){
    var username = body.username

    User.find({where: {username: username}})
    .then(function(_data){
        if(_data){
            return taskFunc()
        }else{
            res.status(400).end()
        }
    })
})

var taskFunc = function(username){
    // function này thời gian xử lý mất nhiều thời gian
    // vì nó cứ nghỉ khoảng 30s mới thực hiện 1 nhiệm vụ khác
}

Sorry ! I mean, after find user response result to client, the taskFunc() only run on server background, client don't know and control taskFunc() — Nam Tran Thanh, Oct 26 '16 at 02:23
Cant You Get The User First And Send The Response To The Client. And Then Invoke Your Task Func? — Shankar Shastri, Oct 26 '16 at 02:30
Let me get this clear - You want to search for the user `AND` if the user doesn't exists you would send a 400 response to client `AND IF THE USER DOES EXIST` you want to return a response to the client and run the `taskFunc()` in the background? — James111, Oct 26 '16 at 02:36

Deepak Bhatia · Answer 1 · 2016-10-26T14:14:08.557

0

I think you are looking something as below:

router.post('/router1, function(req, res){
var username = body.username

User.find({where: {username: username}})
.then(function(_data){
    if(_data){
         setTimeout(taskFunc, 0)
         res.status(200).end()
    }else{
        res.status(400).end()
    }
})
})

var taskFunc = function(username){
// function này thời gian xử lý mất nhiều thời gian
// vì nó cứ nghỉ khoảng 30s mới thực hiện 1 nhiệm vụ khác
}

See here for detail on setTimeout: https://nodejs.org/docs/v0.6.1/api/timers.html

edited Oct 26 '16 at 14:14

answered Oct 26 '16 at 02:05

Deepak Bhatia

1,090
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the taskFunc() just only run on backgroud of server. client don't control it. that is I want. – Nam Tran Thanh Oct 26 '16 at 02:21
I understand your point, that is why I am asking you split you calls into two; first call will returns whether the user exists or not and the second call will return the result of "taskFunc". You can link these calls by using some kind of reference Id. – Deepak Bhatia Oct 26 '16 at 03:43
taskFunc() don't return anything. Can you give me example code? – Nam Tran Thanh Oct 26 '16 at 04:01
Now I got you, see my solution in the answer box. – Deepak Bhatia Oct 26 '16 at 05:16
I tried. But res.status(200).end() still waited until taskFunc complete. – Nam Tran Thanh Oct 26 '16 at 06:17
It should have worked. For now can you try "setTimeout" instead of "process.nextTick"? See the example updated above. – Deepak Bhatia Oct 26 '16 at 14:15
sorry. I was busy. will try and feedback you. – Nam Tran Thanh Oct 26 '16 at 14:34
Yeah. res.status(200).end() has worked. But setTimeout don't work, you know why? – Nam Tran Thanh Oct 28 '16 at 02:51
Don't understand your question, you have to use both res.status(200).end() and setTimeout to solve your problem. Can you post your updated code? – Deepak Bhatia Oct 28 '16 at 05:13
No. This is another question. why I use setTimeout with a function return Promise, but it doesn't working. do you know why ? – Nam Tran Thanh Oct 28 '16 at 06:13
This post: http://stackoverflow.com/questions/40299221/settimeout-dont-working-with-function-return-promise Thanks – Nam Tran Thanh Oct 28 '16 at 06:23
It appears you got you answer for "setTimeout" in that post, right? – Deepak Bhatia Oct 28 '16 at 08:06

score 0 · Answer 2 · answered Oct 26 '16 at 02:59

0

User.find({where: {username: username}})
.then(function(_data){
    if(_data){
        taskFunc()
        res.status(200).send('ok')
    }else{
        res.status(400).end()
    }
})

If i understand correctly, you just want to to send response and run the task in the background?

If so, just do res.status(200).send('ok')

answered Oct 26 '16 at 02:59

Tuan Anh Tran

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@NamTranThanh not effective how? – Tuan Anh Tran Oct 26 '16 at 08:58
Ideally, if it's cpu bound task, you may want to send it to a queue and write a small worker project to process it, separate it from your project. – Tuan Anh Tran Oct 26 '16 at 08:59
thanks. Do you have a demo? I haven't use queue before – Nam Tran Thanh Oct 26 '16 at 10:13

Looking for solutions in Node.js

2 Answers2