Friday 1 May 2015

http request

What is HTTP?

The Hypertext Transfer Protocol (HTTP) is designed to enable communications between clients and servers.
HTTP works as a request-response protocol between a client and server.
A web browser may be the client, and an application on a computer that hosts a web site may be the server.
Example: A client (browser) submits an HTTP request to the server; then the server returns a response to the client. The response contains status information about the request and may also contain the requested content.



Two HTTP Request Methods: GET and POST

Two commonly used methods for a request-response between a client and server are: GET and POST.
  • GET - Requests data from a specified resource
  • POST - Submits data to be processed to a specified resource

 Simple GET request example :


$http.get('/someUrl').
  success(function(data, status, headers, config) {
    // this callback will be called asynchronously
    // when the response is available
  }).
  error(function(data, status, headers, config) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
  });

 Simple POST request example (passing data) :


$http.post('/someUrl', {msg:'hello word!'}).
  success(function(data, status, headers, config) {
    // this callback will be called asynchronously
    // when the response is available
  }).
  error(function(data, status, headers, config) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
  });



In addition, you can supply a headers property in the config object passed when calling $http(config), which overrides the defaults without changing them globally.

To explicitly remove a header automatically added by $httpProvider.defaults.headers on a per request basis, Use the headers property, setting the desired header to undefined. For example:

 var req = {
 method: 'POST',
 url: 'http://example.com',
 headers: {
   'Content-Type': undefined
 },
 data: { test: 'test' }
}

$http(req).success(function(){...})
      .error(function(){...});



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