AngularJS 中 异步请求$http 对象的使用



AngularJS 提供了一个类似jquery的$.ajax的对象，用于异步请求。
在AngularJS中对异步操作是推崇至极的，所以$http的操作都是异步的不像jquery.ajax里还提供了async参数。

对于官网的$http对象的总结和使用。

用法：

$http(config);

参数：

config （常用的参数标红，翻译了一下）

configobject

Object describing the request to be made and how it should be processed. The object has following properties:

• method – {string} – HTTP method (e.g. 'GET', 'POST', etc)  ------------------  http交互方法：GET/POST 两种
• url – {string} – Absolute or relative URL of the resource that is being requested. ------------------  URL传输地址
• params – {Object.<string|Object>} – Map of strings or objects which will be serialized with theparamSerializer and appended as GET parameters.    ------------------  Map 类型的参数，传输给后台
• data – {string|Object} – Data to be sent as the request message data. ------------------  要求传入的参数 
• headers – {Object} – Map of strings or functions which return strings representing HTTP headers to send to the server. If the return value of a function is null, the header will not be sent. Functions accept a config object as an argument.
• xsrfHeaderName – {string} – Name of HTTP header to populate with the XSRF token.
• xsrfCookieName – {string} – Name of cookie containing the XSRF token.
• transformRequest – {function(data, headersGetter)|Array.<function(data, headersGetter)>} – transform function or an array of such functions. The transform function takes the http request body and headers and returns its transformed (typically serialized) version. See Overriding the Default Transformations
• transformResponse –{function(data, headersGetter, status)|Array.<function(data, headersGetter, status)>} – transform function or an array of such functions. The transform function takes the http response body, headers and status and returns its transformed (typically deserialized) version. See Overriding the Default TransformationjqLiks
• paramSerializer - {string|function(Object<string,string>):string} - A function used to prepare the string representation of request parameters (specified as an object). If specified as string, it is interpreted as function registered with the $injector, which means you can create your own serializer by registering it as a service. The default serializer is the $httpParamSerializer; alternatively, you can use the$httpParamSerializerJQLike
• cache – {boolean|Cache} – If true, a default $http cache will be used to cache the GET request, otherwise if a cache instance built with $cacheFactory, this cache will be used for caching. ------------------  缓存，设为true的时候,默认的$ HTTP缓存将用于缓存GET请求，否则，创建Factory缓存实例.
• timeout – {number|Promise} – timeout in milliseconds, or promise that should abort the request when resolved.
• withCredentials - {boolean} - whether to set the withCredentials flag on the XHR object. See requests with credentials for more information.
• responseType - {string} - see XMLHttpRequest.responseType.

返回： 一个httpPromise对象(一般只用data和status)

HttpPromise

Returns a promise object with the standard then method and two http specific methods: success and error. Thethen method takes two arguments a success and an error callback which will be called with a response object. Thesuccess and error methods take a single argument - a function that will be called when the request succeeds or fails respectively. The arguments passed into these functions are destructured representation of the response object passed into the then method. The response object has these properties:

• data – {string|Object} – The response body transformed with the transform functions.  ------------------  返回数据
• status – {number} – HTTP status code of the response. ------------------  返回状态。等于200时为成功，否则失败。
• headers – {function([headerName])} – Header getter function.
• config – {Object} – The configuration object that was used to generate the request.  ------------------  用于生成请求的配置对象，原来传入的参数等。
• statusText – {string} – HTTP status text of the response. ------------------  返回的状态文本

方法：

get(url, [config]);         快捷的方法来执行GET请求。

post(url, data, [config]);  快捷的方法来执行POST请求。

put(url, data, [config]);

patch(url, data, [config]);

jsonp(url, [config]);

head(url, [config]);

delete(url, [config]);

我自己的使用例子（使用promise解决回调地狱问题）

          var deferred = $q.defer();          $http({            cache: false,            method: 'GET',            url: Constants.baseURL + '/loginj',            params: params,            headers: {'X-Auth-Token': $window.token}          }).then(function(res) {            if (200 === res.status && res.data.LoginResponse.success) {              if (!Array.isArray(res.data.LoginResponse.settings.account)) {                res.data.LoginResponse.settings.account = [res.data.LoginResponse.settings.account];              }                            CurrentUser.id = res.data.LoginResponse.settings.id;                            deferred.resolve(res.data.LoginResponse.settings);            } else {              deferred.reject("failed to fetch login data");            }          }, function(error) {              deferred.reject(error.status+" "+error.statusText);          });          return deferred.promise;

官网地址：https://docs.angularjs.org/api/ng/service/$http （需要翻墙）

参考文章：http://zhaoyanblog.com/archives/99.html