Angular - abort ajax request when using Restangula

问题:

I have a method that calls an angular service and consequently makes an ajax request via the service. I need to make sure that if this is called several times, the previous request in aborted (if it hasn't already been resolved that is).

This method can get called multiple times. This method is actually from ngTable on ngTableParams:

getData = function($defer, params) {

      myService.getRecord(params).then(function(res){ 
             ...
             $defer.resolve(res.Records);
      }); 
}

Here's the method on the service:

this.getRecords = function(params) {
    ...

    return Restangular
          .all('/api/records')
          .post(filters);
};

If ngTable makes 3 calls I want the first 2 to be aborted (unless of course they returned so fast that it got resolved)

回答1:

You can abort $http calls via the timeout config property, which can be a Promise, that aborts the request when resolved.

So in restangular, you can do this like

var abort = $q.defer();
Restangular.one('foos', 12345).withHttpConfig({timeout: abort.promise}).get();
abort.resolve();

To integrate it with your usecase, for example, you could have this in your service:

var abortGet;

this.getRecords = function(params) {
  ...
  if (abortGet) abortGet.resolve();
  abortGet = $q.defer();
  return Restangular
    .all('/api/records')
    .withHttpConfig({timeout: abortGet.promise})
    .post(filters);
}

This way calling getRecords always aborts the previous call if has not been resolved yet!

Hope this helps!

回答2:

This is another approach if you want to abort all http requests when change the state for UI-router:

angular
    .run(function(HttpHandlerSrv) {
        HttpHandlerSrv.abortAllRequestsOn('$stateChangeSuccess');
        HttpHandlerSrv.R.setFullRequestInterceptor(function(element, operation, route, url, headers, params, httpConfig) {
            httpConfig = httpConfig || {};
            if(httpConfig.timeout === undefined) {
                httpConfig.timeout = HttpHandlerSrv.newTimeout();
            }
            return { element: element, params: params, headers: headers, httpConfig: httpConfig };
        });
    })

    .factory('HttpHandlerSrv', HttpHandlerSrv);


    /** ngInject */
    function HttpHandlerSrv($q, $rootScope, Restangular) {
        var requests = [];

        return {
            R: Restangular,
            newTimeout: newTimeout,
            abortAllRequests: abortAllRequests,
            abortAllRequestsOn: abortAllRequestsOn
        };

        function newTimeout() {
            var request = $q.defer();
            requests.push(request);
            return request.promise;
        }

        function abortAllRequests() {
            angular.forEach(requests, function(request) {
                request.resolve();
            });
            requests = [];
        }

        function abortAllRequestsOn(event) {
            $rootScope.$on(event, function(event, newUrl, oldUrl) {
                if(newUrl !== oldUrl) { abortAllRequests(); }
            });
        }
    }