CODEWITHSUNDEEP
javascriptangularjshttpgethttp-get
mayankcpdixit
mayankcpdixit

Reputation: 2464

How to deal with "Random HTTP GET" error

I need to send multiple get requests(required) one by one. When the count is 2-3, it works fine, but with almost 6 HTTP Get requests, sometimes some of them fails and give Internal Sever Error(500). Opening the error link in new tab gives required results.

So there is nothing wrong from server side.

I'm facing this problem both in : localhost and production. How to deal with this situation from client side?

I've tried:

  1. NodeJS + SocketIO to send data from server without asking. [with so much data if socket keeps writing till 60 sec. socket re-registers & restarts from beginning.]
  2. Angular + NGResource. [internally uses http get. issue persists.]
  3. Angular + Restangular Lib. [internally uses http get. issue persists.]

Please suggest how do I know what the problem is. Then only I can think of a solution.

Thnx!!

Upvotes: 2

Views: 486

Answers (1)

Robert Balicki
Robert Balicki

Reputation: 1633

Here's a function in which you can wrap your HTTP calls. It will repeat the call until it passes. Beware! If the HTTP call fails 100% of the time (for example, malformed URL), then the function will not stop (In testing, the function was called >70,000 times. Apparently there is no recursion limit with promises). For that case, I've included a limited version of the function that stops after n attempts.

var persistentRequest = function(requestFn) {
  var deferred = $q.defer();
  requestFn().then(function() {
    deferred.resolve();
  }, function() {
    persistentRequest(requestFn).then(
      function() {
        deferred.resolve();
      }
    );
  });

  return deferred.promise;
}

var persistentRequestLimited = function(requestFn, n) {
  var deferred = $q.defer();
  if (n <= 0) {
    deferred.reject('Did not complete in given number of tries');
  } else {
    requestFn().then(function(data) {
      deferred.resolve(data);
    }, function() {
      persistentRequestLimited(requestFn, n-1).then(
        function(data) {
          deferred.resolve(data);
        },
        function(rejection) {
          deferred.reject(rejection);
        }
      );
    });
  }

  return deferred.promise;
}

For example, use it like:

persistentRequest(function() {
  return $http.get('/myurl');
});

persistentRequestLimited(function() {
  return $http.get('/myurl');
}, 10);

Don't forget to inject $q into your controller/service/etc.

Upvotes: 1

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