Angularjs中的拦截器
$httpAngularJS 的 什么是拦截器? <!-- lang: js --> module.factory('myInterceptor',['$log',function($log) { $log.debug('$log is here to show you that this is a regular factory with injection'); var myInterceptor = { .... .... .... }; return myInterceptor; }]);
然后通过它的名字添加到 <!-- lang: js --> module.config(['$httpProvider',function($httpProvider) { $httpProvider.interceptors.push('myInterceptor'); }]);
拦截器允许你:
有时候需要在拦截器中做一些异步操作。幸运的是, AngularJS 允许我们返回一个 <!-- lang: js -->
module.factory('myInterceptor',['$q','someAsyncService',function($q,someAsyncService) { var requestInterceptor = { request: function(config) { var deferred = $q.defer(); someAsyncService.doAsyncOperation().then(function() { // Asynchronous operation succeeded,modify config accordingly ... deferred.resolve(config); },function() { // Asynchronous operation failed,modify config accordingly ... deferred.resolve(config); }); return deferred.promise; } }; return requestInterceptor; }]);
这个例子中,请求拦截器使用了一个异步操作,根据结果来更新配置。然后它用更新后的配置继续执行操作。如果 响应拦截器的例子一样: function(response) { var deferred = $q.defer(); someAsyncService.doAsyncOperation().then(function() { // Asynchronous operation succeeded,modify response accordingly ... deferred.resolve(response); },modify response accordingly ... deferred.resolve(response); }); return deferred.promise; } }; return responseInterceptor; }]);
只有当 例子本节中我将提供一些 AngularJS 拦截器的例子,以便让你更好的理解它们是如何使用的,并且可以展示一下它们能怎样帮助你。不过请记住,我这里提供的解决案不一定是最好或者最准确的解决案。 Session 注入(请求拦截器) 这里有两种方式来实现服务端的认证。第一种是传统的 下面的 <!-- lang: js -->
module.factory('sessionInjector',['SessionService',function(SessionService) { var sessionInjector = { request: function(config) { if (!SessionService.isAnonymus) { config.headers['x-session-token'] = SessionService.token; } return config; } }; return sessionInjector; }]); module.config(['$httpProvider',255)">function($httpProvider) { $httpProvider.interceptors.push('sessionInjector'); }]);
然后创建一个请求: <!-- lang: js --> $http.get('https://api.github.com/users/naorye/repos');
被 <!-- lang: js --> { "transformRequest": [ null ],"transformResponse": [ null ],21)">"method": "GET","url": "https://api.github.com/users/naorye/repos","headers": { "Accept": "application/json,text/plain,*/*" } }
被 ,"x-session-token": 415954427904 } }
时间戳(请求和响应拦截器)让我们用拦截器来测一下从后台返回响应需要多少时间。可以通过给每个请求和响应加上时间戳。 'timestampMarker',[function() { var timestampMarker = { request: function(config) { config.requestTimestamp = new Date().getTime(); return config; },response: function(response) { response.config.responseTimestamp = new Date().getTime(); return response; } }; return timestampMarker; }]); module.config(['timestampMarker'); }]);
然后我们可以这样: <!-- lang: js --> $http.get('https://api.github.com/users/naorye/repos').then(function(response) { var time = response.config.responseTimestamp - response.config.requestTimestamp; console.log('The request took ' + (time / 1000) + ' seconds.'); });
完整代码:example for the Timestamp Marker 请求恢复 (请求异常拦截)为了演示请求异常拦截,我们需要模拟前一个拦截器拒绝了请求这种情况。我们的请求异常拦截器会拿到被拒绝的原因以及恢复请求。 让我们来创建两个拦截器: 'requestRejector',255)">function($q) { var requestRejector = { request: function(config) { return $q.reject('requestRejector'); } }; return requestRejector; }]); module.factory('requestRecoverer',255)">var requestRecoverer = { requestError: function(rejectReason) { if (rejectReason === 'requestRejector') { // Recover the request return { transformRequest: [],transformResponse: [],method: 'GET',url: 'https://api.github.com/users/naorye/repos',headers: { Accept: 'application/json,*/*' } }; } else { return $q.reject(rejectReason); } } }; return requestRecoverer; }]); module.config([function($httpProvider) { $httpProvider.interceptors.push('requestRejector'); // Removing 'requestRecoverer' will result to failed request $httpProvider.interceptors.push('requestRecoverer'); }]);
然后,如果你像下面这样请求,我们会在 log 中看到 <!-- lang: js --> $http.get('https://api.github.com/users/naorye/repos').then(function() { console.log('success'); },255)">function(rejectReason) { console.log('failure'); });
完整代码:example for the Request Recover Session 恢复 (响应异常拦截器)有时候,我们的单页面应用中,会发生丢失 session 情况。这种情况可能由于 session 过期了或者服务器异常。我们来创建一个拦截器,用于恢复 session 然后自动重新发送原始请求(假设 session 过期的情况)。 为了演示目的,我们来假设发生了 session 过期返回 http 状态码 419。 'sessionRecoverer','$injector',255)">function($q,$injector) { var sessionRecoverer = { responseError: function(response) { // Session has expired if (response.status == 419){ var SessionService = $injector.get('SessionService'); var $http = $injector.get('$http'); var deferred = $q.defer(); // Create a new session (recover the session) // We use login method that logs the user in using the current credentials and // returns a promise SessionService.login().then(deferred.resolve,deferred.reject); // When the session recovered,make the same backend call again and chain the request return deferred.promise.then(function() { return $http(response.config); }); } return $q.reject(response); } }; return sessionRecoverer; }]); module.config(['sessionRecoverer'); }]);
以这种方式,如果后台调用失败引起 session 过期, (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |