Question

我正在试图弄清楚如何使用$ resource的timeout属性动态取消挂起的请求。理想情况下，我希望能够取消具有某些属性的请求（基于发送的参数），但似乎这可能是不可能的。与此同时，我只是尝试取消所有挂起的请求，然后重置超时承诺以允许新请求。

问题似乎是$ resource配置只允许一个静态的超时值承诺。如果我正在进行单独的$ http调用，那么我可以做到这一点是有道理的，因为我可以为超时传递新的承诺，但是如何才能为$资源工作呢？我在这里设置了一个示例plunker：http://plnkr.co/edit/PP2tqDYXh1NAOU3yqCwP?p=preview

这是我的控制器代码：

app.controller('MainCtrl', function($scope, $timeout, $q, $resource) {
  $scope.canceller = $q.defer();
  $scope.pending = 0;
  $scope.actions = [];
  var API = $resource(
    'index.html', {}, {
      get: {
        method: 'GET',
        timeout: $scope.canceller.promise
      }
    }
  )

  $scope.fetchData = function() {
    if ($scope.pending) {
      $scope.abortPending();
    }
    $scope.pending = 1;
    $scope.actions.push('request');
    API.get({}, function() {
      $scope.actions.push('completed');
      $scope.pending = 0;
    }, function() {
      $scope.actions.push('aborted');
    });
  }

  $scope.abortPending = function() {
    $scope.canceller.resolve();
    $scope.canceller = $q.defer();
  }
});

现在，当有待处理的请求时，取消器工作，但我似乎无法重置它 - 一旦一个请求被中止，所有未来的请求也将被中止。

我确定我错过了一些东西，因为能够取消待处理的请求似乎是大多数Web应用程序的一个非常重要的功能（至少我已经构建了）。

由于

Answer 1

Gecko IT的回答对我有用，但我必须做一些修改才能：

启用资源ajax调用以多次取消，而无需重新创建资源
使资源向后兼容 - 这意味着无需更改除资源工厂之外的任何应用程序（Controller）代码
使代码符合JSLint

这是完整的服务工厂实现（您只需要输入正确的模块名称）：

'use strict';

/**
 * ResourceFactory creates cancelable resources.
 * Work based on: https://stackoverflow.com/a/25448672/1677187
 * which is based on: https://developer.rackspace.com/blog/cancelling-ajax-requests-in-angularjs-applications/
 */
/* global array */
angular.module('module_name').factory('ResourceFactory', ['$q', '$resource',
    function($q, $resource) {

        function abortablePromiseWrap(promise, deferred, outstanding) {
            promise.then(function() {
                deferred.resolve.apply(deferred, arguments);
            });

            promise.catch(function() {
                deferred.reject.apply(deferred, arguments);
            });

            /**
             * Remove from the outstanding array
             * on abort when deferred is rejected
             * and/or promise is resolved/rejected.
             */
            deferred.promise.finally(function() {
                array.remove(outstanding, deferred);
            });
            outstanding.push(deferred);
        }

        function createResource(url, options, actions) {
            var resource;
            var outstanding = [];
            actions = actions || {};

            Object.keys(actions).forEach(function(action) {
                var canceller = $q.defer();
                actions[action].timeout = canceller.promise;
                actions[action].Canceller = canceller;
            });

            resource = $resource(url, options, actions);

            Object.keys(actions).forEach(function(action) {
                var method = resource[action];

                resource[action] = function() {
                    var deferred = $q.defer(),
                    promise = method.apply(null, arguments).$promise;

                    abortablePromiseWrap(promise, deferred, outstanding);

                    return {
                        $promise: deferred.promise,

                        abort: function() {
                            deferred.reject('Aborted');
                        },
                        cancel: function() {
                            actions[action].Canceller.resolve('Call cancelled');

                            // Recreate canceler so that request can be executed again
                            var canceller = $q.defer();
                            actions[action].timeout = canceller.promise;
                            actions[action].Canceller = canceller;
                        }
                    };
                };
            });

            /**
             * Abort all the outstanding requests on
             * this $resource. Calls promise.reject() on outstanding [].
             */
            resource.abortAll = function() {
                for (var i = 0; i < outstanding.length; i++) {
                    outstanding[i].reject('Aborted all');
                }
                outstanding = [];
            };

            return resource;
        }

        return {
            createResource: function (url, options, actions) {
                return createResource(url, options, actions);
            }
        };
    }
]);

用法与Gecko IT示例相同。服务工厂：

'use strict';

angular.module('module_name').factory('YourResourceServiceName', ['ResourceFactory', function(ResourceFactory) {
    return ResourceFactory.createResource('some/api/path/:id', { id: '@id' }, {
        create: {
            method: 'POST'
        },
        update: {
            method: 'PUT'
        }
    });
}]);

控制器中的用法（向后兼容）：

var result = YourResourceServiceName.create(data);
result.$promise.then(function success(data, responseHeaders) {
    // Successfully obtained data
}, function error(httpResponse) {
    if (httpResponse.status === 0 && httpResponse.data === null) { 
        // Request has been canceled
    } else { 
        // Server error 
    }
});
result.cancel(); // Cancels XHR request

替代方法：

var result = YourResourceServiceName.create(data);
result.$promise.then(function success(data, responseHeaders) {       
    // Successfully obtained data
}).catch(function (httpResponse) {
    if (httpResponse.status === 0 && httpResponse.data === null) { 
        // Request has been canceled
    } else { 
        // Server error 
    }
});
result.cancel(); // Cancels XHR request

进一步改进：

我不想检查请求是否已被取消。更好的方法是在请求被取消时附加属性httpResponse.isCanceled，并且类似于中止。

Answer 2

（对于Angular 1.2.28+）大家好，我只是想让它易于理解，我如何处理该问题如下：

这里我声明了超时参数

$scope.stopRequestGetAllQuestions=$q.defer();

然后在我使用它如下

return $resource(urlToGet, {}, {get:{ timeout: stopRequestGetAllQuestions.promise }});

如果我想停止以前的$ resource调用，我只需要解析这个stopRequestGetAllQuestions对象。

stopRequestGetAllQuestions.resolve();

但如果我想停止之前的那个并开始一个新的$ resource调用，那么我会在stopRequestGetAllQuestions.resolve();之后执行此操作：

stopRequestGetAllQuestions = $q.defer();

Answer 3

目前有很多例子。我发现以下两个内容非常丰富：

这一个显示了如何处理$ resource和$ http请求的示例： https://developer.rackspace.com/blog/cancelling-ajax-requests-in-angularjs-applications/

和

这个更简单，只适用于$ http： http://odetocode.com/blogs/scott/archive/2014/04/24/canceling-http-requests-in-angularjs.aspx

Answer 4

您好我根据https://developer.rackspace.com/blog/...

制作了自定义处理程序

.factory('ResourceFactory', ["$q", "$resource", function($q, $resource) {
    function createResource(url, options, actions) {
        var actions = actions || {},
        resource,
        outstanding = [];

        Object.keys(actions).forEach(function (action) {
            console.log(actions[action]);
            var canceller = $q.defer();
            actions[action].timeout = canceller.promise;
            actions[action].Canceller = canceller;
        });

        resource = $resource(url, options, actions);

        Object.keys(actions).forEach(function (action) {
            var method = resource[action];

            resource[action] = function () {
                var deferred = $q.defer(),
                promise = method.apply(null, arguments).$promise;

                abortablePromiseWrap(promise, deferred, outstanding);

                return {
                    promise: deferred.promise,

                    abort: function () {
                        deferred.reject('Aborted');
                    },
                    cancel: function () {
                        console.log(actions[action]);
                        actions[action].Canceller.resolve("Call cancelled");
                    }
                };
            };
        });

        /**
        * Abort all the outstanding requests on
        * this $resource. Calls promise.reject() on outstanding [].
        */
        resource.abortAll = function () {
            for (var i = 0; i < outstanding.length; i++) {
                outstanding[i].reject('Aborted all');
            }
            outstanding = [];
        };

        return resource;
    }

    return {
        createResource: function (url, options, actions) {
            return createResource(url, options, actions);
        }
    }
}])

function abortablePromiseWrap(promise, deferred, outstanding) {
    promise.then(function () {
        deferred.resolve.apply(deferred, arguments);
    });

    promise.catch(function () {
        deferred.reject.apply(deferred, arguments);
    });
    /**
    * Remove from the outstanding array
    * on abort when deferred is rejected
    * and/or promise is resolved/rejected.
    */
    deferred.promise.finally(function () {
        array.remove(outstanding, deferred);
    });
    outstanding.push(deferred);
}


//Usage SERVICE
factory("ServiceFactory", ["apiBasePath", "$resource", "ResourceFactory", function (apiBasePath, $resource, QiteResourceFactory) {
    return ResourceFactory.createResource(apiBasePath + "service/:id", { id: '@id' }, null);
}])

//Usage Controller
var result = ServiceFactory.get();
console.log(result);
result.promise.then(function (data) {       
    $scope.services = data;
}).catch(function (a) {
    console.log("catch", a);
})
//Actually cancels xhr request
result.cancel();

Answer 5

一种解决方案是每次需要时重新创建资源。

// for canceling an ajax request
$scope.canceler = $q.defer();

// create a resource
// (we have to re-craete it every time because this is the only
// way to renew the promise)
function getAPI(promise) {
    return $resource(
        'index.html', {}, {
            get: {
                method: 'GET',
                timeout: promise
            }
        }
    );
}

$scope.fetchData = function() {

    // abort previous requests if they are still running
    $scope.canceler.resolve();

    // create a new canceler
    $scope.canceler = $q.defer();

    // instead of using "API.get" we use "getAPI().get"
    getAPI( $scope.canceler.promise ).get({}, function() {
        $scope.actions.push('completed');
        $scope.pending = 0;
    }, function() {
        $scope.actions.push('aborted');
    });

}

Answer 6

在我们尝试解决此任务时，我们得到了以下解决方案：

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8" />
  <title>Cancel resource</title>
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.9/angular.js"></script>
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.9/angular-resource.js"></script>
  <script>
angular.module("app", ["ngResource"]).
factory(
  "services",
  ["$resource", function($resource)
  {
    function resolveAction(resolve)
    {
      if (this.params)
      {
        this.timeout = this.params.timeout;
        this.params.timeout = null;
      }

      this.then = null;
      resolve(this);
    }

    return $resource(
      "http://md5.jsontest.com/",
      {},
      {
        MD5:
        {
          method: "GET",
          params: { text: null },
          then: resolveAction
        },
      });
  }]).
controller(
  "Test",
  ["services", "$q", "$timeout", function(services, $q, $timeout)
  {
    this.value = "Sample text";
    this.requestTimeout = 100;

    this.call = function()
    {
      var self = this;

      self.result = services.MD5(
      {
        text: self.value,
        timeout: $q(function(resolve)
        {
          $timeout(resolve, self.requestTimeout);
        })
      });
    }
  }]);
  </script>
</head>
<body ng-app="app" ng-controller="Test as test">
  <label>Text: <input type="text" ng-model="test.value" /></label><br/>
  <label>Timeout: <input type="text" ng-model="test.requestTimeout" /></label><br/>
  <input type="button" value="call" ng-click="test.call()"/>
  <div ng-bind="test.result.md5"></div>
</body>
</html>

如何运作

$ resource合并操作定义，请求参数和数据以构建$ http请求的配置参数。
传递给$ http请求的配置参数被视为类似对象的promise，因此它可能包含初始化配置的函数。
action的then函数可以将超时承诺从params传递到config。

有关详细信息，请查看“Cancel Angularjs resource request”。

如何取消$资源请求

6 个答案:

如何运作