http拦截
,即$http服务允许我们与服务端交互,有时候我们希望在发出请求之前以及收到响应之后做些事情。 $httpProvider包含了一个interceptors的数组。我们这样创建一个interceptor。
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app.factory('myInterceptor',['$log',function($log){
$log.debug('');
var myInterceptor = {};
return myInterceptor;
}])
接着注册interceptor.
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app.config(['$httpProvider',function($httpProvider){
$httpProvider.interceptors.push('myInterceptor');
}])
以下是$http拦截的一些例子。
■ 拦截器中的异步操作
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app.factory('myInterceotpr','someAsyncServcie',function($q,someAsyncServcie){
var requestInterceptor = {
request: function(config){
var deferred = %q.defer();
someAsyncService.doAsyncoperation().then(function(){
...
deferred.resolve(config);
},function(){
...
deferred.resolve(config);
})
return deferred.promise;
}
};
return requestInterceptor;
})
以上,是一个请求拦截,做了一个异步操作,根据异步操作的结果来更新config。
当然也有响应拦截。
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app.factory('myInterceptor',['$q','someAsyncService',someAsyncSercice){
var responseInterceptor = {
response: function(response){
var deferred = $q.defer();
someAsyncService.doAsyncoperation().then(function(response){
...
deferred.resolve(response);
},function(response){
...
deferred.resolve(response);
})
return deferred.promise;
}
};
return responseInterceptor;
}])
服务端有2种类型的验证,一个是基于cookie的,一种是基于token的。对于基于token验证,当用户登录,获取一个来自服务端的token,这个token在每一次请求时发送给服务端。
创建一个有关session的injector:
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app.factory('sessionInjector',['SessionService',function(SessionService){
var sessionInjector = {
request: function(config){
if(!SessionService.isAnonymous){
config.headers['x-session-token'] = SessionService.token;
}
return config;
}
};
return sessionInjector;
}])
可见,把从服务端返回的token放在了config.headers中。
注册injector:
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app.config(['$httpProvider',function($httpProvider){
$httpProvider.interceptors.push('sessionInjector');
}])
发出一个请求:
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$http.get('');
拦截前大致是:
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{
"transformRequest":[null],"transformResponse":[null],"method":"GET","url":"","headers":{
"Accept": "application/json,text/plain,*/*"
}
}
拦截后,在headers中多两个一个x-session-token字段:
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{
"transformRequest":[null],*/*","x-session-token":......
}
}
■ 时间戳,请求和响应拦截
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app.factory('timestampMarker',[function(){
var timestampMarker = {
request:function(config){
config.requestTimestamp = new Date().getTime();
return config;
},response: function(response){
response.config.responseTimestamp = new Date().getTime();
return config;
}
};
return timestampMarker;
}])
以上,在请求和响应时拦截,在config.requestTimestamp和config.responseTimestamp赋上当前的时间。
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app.config(['$httpProvider',function($httpProvider){
$httpProvider.interceptors.push('timestampMarker');
}])
然后在运用的时候可以算出请求响应所耗去的时间。
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$http.get('').then(function(response){
var time = response.config.responseTime - response.config.requestTimestamp;
console.log('请求耗去的时间为 ' + time);
})
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app.factory('requestRejector',function($q){
var requestRejector = {
request: function(config){
return $q.reject('requestRejector');
}
};
return requestRejector;
}])
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app.factory('requestRecoverer',function($q){
var requestRecoverer = {
requestError: function(rejectReason){
if(rejectReason === 'requestRejector'){
//恢复请求
return {
transformRequest:[],transformResponse:[],method:'GET',url:'',headers:{
Accept:'application/json,*/*'
}
};
} else {
return $q.reject(rejectReason);
}
}
};
return requestRecoverer;
}])
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app.config(['$httpProvider',function($httpProvider){
$httpProvider.interceptors.push('requestRejector');
$httpProvider.interceptors.push('requestRecoverer');
}])
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app.factory('sessionRecoverer','$injector',$injector){
var sessionRecoverer = {
responseError: function(response){
//如果Session过期
if(response.status == 419){
var SessionService = $injector.get('SessionService');
var $http = $injector.get('$http');
var deferred = $q.defer();
//创建<a href="https://www.jb51.cc/tag/yige/" target="_blank" class="keywords">一个</a>新的session
SessionService.login().then(deferred.resolve,deferred.reject);
return deferred.promise.then(function(){
reutrn $http(response.con<a href="https://www.jb51.cc/tag/fig/" target="_blank" class="keywords">fig</a>);
})
}
return $q.reject(response);
}
};
return sessionRecoverer;
}])
以上就是本文的全部内容,希望对大家的学习有所帮助。