CODEWITHSUNDEEP
node.jscallback
konquestor
konquestor

Reputation: 1308

nodejs: force callback execution if method hangs

i have a situation where my asynchronus nodejs method from a third party library is taking too long. i want to set a timeout limit on this call and if it does not return within that timeout, i want a callback to happen with default(empty) values.

current code

wrapperfunct(data, function(value, err) {
  //do everything with value or err
})


wrapperfunc(data, callback) {
      thirdpartylib.getData(input, callback)
    }

i am noticing that getData sometimes hangs, that prevents the callback from happening. i want a behavior than if getData does not call the callback method in specified time, i call callback with default values, say (null, null).

Upvotes: 2

Views: 420

Answers (1)

jfriend00
jfriend00

Reputation: 707696

You can make your own timeout like this:

wrapperfunc(obj, timeout, data, callback) {
   var done = false;
   var timer = setTimeout(function() {
       done = true;
       // callback with both values null to signify a timeout
       callback(null, null);
   }, timeout);
   obj.thirdpartylib.getData(input, function(err, data) {
       if (!done) {
           clearTimeout(timer);
           done = true;
           callback(err, data);
       }
   })
}

Note: The value of this in your proposed function was probably not correct so I substituted obj. You will either have to pass that value in or you will have to use some variable that is within scope for that.

Upvotes: 3

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