How to use http server in angularjs

This time I will show you how to use the http server in angularjs, and what are the precautions for using the http server in angularjs. The following is a practical case, let's take a look.

We can use the built-in $http service to communicate directly with the outside world. The $http service simply encapsulates the browser's native XMLHttpRequest object.

1. Chain call

#$http service is a function that can only accept one parameter. This parameter is an object, including the To generate the configuration content of the HTTP request. This function returns a promise object with two methods: success and error.

$http({ url:'data.json', method:'GET' }).success(function(data,header,config,status){ //响应成功 }).error(function(data,header,config,status){ //处理响应失败 });

2. Return a promise object

var promise=$http({ method:'GET', url:"data.json" });

Since the $http method returns a promise object, we can use the then method when the response returns to handle callbacks. If you use the then method, you will get a special parameter, which represents the success or failure information of the corresponding object, and can also accept two optional functions as parameters. Or you can use success and error callbacks instead.

promise.then(function(resp){ //resp是一个响应对象 },function(resp){ //带有错误信息的resp });

Or like this:

promise.success(function(data,status,config,headers){ //处理成功的响应 }); promise.error(function(data,status,hedaers,config){ //处理失败后的响应 });

The main difference between the then() method and the other two methods is that it will receive the complete response object, while success() and error() will Destruct the response object.

3. Quick get request

①$http.get('/api/users.json');

get() method returns HttpPromise object.

You can also send, for example: delete/head/jsonp/post/put. Please refer to page 148 for specific parameters acceptable in the function.

② Take the example of sending a jsonp request again: In order to send a JSONP request, where The url must contain the words JSON_CALLBACK.

jsonp(url,config) where config is optional

var promise=$http.jsonp("/api/users.json?callback=JSON_CALLBACK");

4. You can also use $http as a function. In this case, you need to pass in a setting Object, used to illustrate how to construct an XHR object.

$http({ method:'GET', url:'/api/users.json', params:{ 'username':'tan' });

The setting object can contain the following main keys:

①method

can be: GET/DELETE/HEAD/JSONP/POST/PUT

②url: absolute or relative request target

③params (string map or object)

The value of this key is a string map or object, which will be converted The query string is appended to the URL. If the value is not a string, it will be JSON serialized.

For example:

//参数会转为？name=ari的形式 $http({ params:{'name':'ari'} });

④data (string or object)

This object contains the data that will be sent to the server as the message body. Typically used when sending POST requests.

Starting from AngularJS 1.3, it can also send binary data in POST requests. To send a blob object, you can simply pass it by using the data parameter.

For example:

var blob=new Blob(['Hello world'],{type:'text/plain'}); $http({ method:'POST', url:'/', data:blob });

4. Response object

The response object passed by AngularJS to the then() method contains four attributes.

◇data: This data represents the converted response body (if conversion is defined)

◇status: The HTTP status code of the response

◇headers: This function is The getter function of the header information can accept a parameter to obtain the corresponding name value

For example, use the following code to obtain the value of X-Auth-ID:

$http({ method: 'GET', url: '/api/users.json' }).then (resp) { // 读取X-Auth-ID resp.headers('X-Auth-ID'); });

◇config: This object is The complete settings object used to generate the original request.

◇statusText (string): This string is the HTTP status text of the response.

5. Caching HTTP requests

By default, the $http service does not cache requests locally. When making individual requests, we can enable caching by passing a boolean value or a cache instance to the $http request.

$http.get('/api/users.json',{ cache: true }) .success(function(data) {}) .error(function(data) {});

The first time a request is sent, the $http service will send a GET request to /api/users.json. When the same GET request is sent for the second time, the $http service will retrieve the request result from the cache without actually sending an HTTP GET request.
In this example, because caching is enabled, AngularJS will use $cacheFactory by default. This service is automatically created by AngularJS when it starts.

If you want more custom control over the cache used by AngularJS, you can pass a custom cache instance to the request instead of true.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

Summary of commonly used JavaScript interception string methods

How to use vue keep-alive to request data

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