$http service cache when the method is post

Question

when I set the $http to cache requests, I still see duplicate requests (with the same url and same data) sent to the server from browser network,

$http.post(url, data, {cache:true} ).success(function(response) {

I have following questions:

• Is this a right behaviour?
• Can we cache post requests?
• Is this the right way to do so or should I be doing it manually with the $cachefactory ?

Answer 1

From the docs:

Only GET and JSONP requests are cached.

If you want to cache POST-requests you would have to do it manually. You will need to make a service/factory that caches responses and serves as a layer before $http. You can use $cacheFactory or just a plain object.

function cacheService($http, $q){      
  var cache = {};      
  this.callSomething = function(postData){
    let deferred = $q.defer();
    let hash = angular.toJson(postData);
    if(cache[hash]){
      deferred.resolve(cache[hash]);
    } else {
      $http.post('path/to/resource', postData).then(function(response){
        cache[hash] = response;
        deferred.resolve(response);
      });
    }        
    return deferred.promise;
  }
}

This is a simple example, you could of course use the same principle and make a more generalized service that takes an URL, postData and a cache object and returns a function that does the request and caches it.

Answer 2

I am not sure about cache working. But you can use $cacheFactory for same.

app.factory('Cache', function ($cacheFactory) {
    return $cacheFactory('Cache');
});

app.controller('MyController', function ($scope, $http, Cache) {
    $http.post(url, data, {cache:Cache} ).success(function(response) {}
});

EDIT:

Only GET and JSONP requests are cached.

The cache key is the request URL including search parameters; headers are not considered.

Cached responses are returned asynchronously, in the same way as responses from the server.

If multiple identical requests are made using the same cache, which is not yet populated, one request will be made to the server and remaining requests will return the same response.

A cache-control header on the response does not affect if or how responses are cached.