How to get Response Header location from jQuery Ge

问题:

So I am trying to get the location from a header response via jQuery get. I tried using getResponseHeader('Location') and getAllResponseHeaders() but they both seem to return null.

Here's my current code

$(document).ready(function(){
   var geturl;
   geturl = $.ajax({
      type: "GET",
      url: 'http://searchlight.cluen.com/E5/Login.aspx?URLKey=uzr7ncj8)',
   });
   var locationResponse = geturl.getResponseHeader('Location');
   console.log(locationResponse);
});

回答1:

The headers will be available when the asynchronous request returns, so you will need to read them in the success callback:

$.ajax({
    type: "GET",
    url: 'http://searchlight.cluen.com/E5/Login.aspx?URLKey=uzr7ncj8)',
    success: function(data, status, xhr) {
        console.log(xhr.getResponseHeader('Location'));
    }
});

回答2:

for some headers in jQuery Ajax you need to access XMLHttpRequest object

var xhr;
var _orgAjax = jQuery.ajaxSettings.xhr;
jQuery.ajaxSettings.xhr = function () {
  xhr = _orgAjax();
  return xhr;
};

$.ajax({
    type: "GET",
    url: 'http://example.com/redirect',
    success: function(data) {
        console.log(xhr.responseURL);
    }
});

or using plain javascript

var xhr = new XMLHttpRequest();
xhr.open('GET', "http://example.com/redirect", true);

xhr.onreadystatechange = function () {
  if (this.readyState == 4 && this.status == 200) {
    console.log(xhr.responseURL);
  }
};

xhr.send();

回答3:

jQuery abstracts the XMLHttpRequest object in a so-called "super set" that does not expose the responseURL field. It's in their docs where they talk about the "jQuery XMLHttpRequest (jqXHR) object"

For backward compatibility with XMLHttpRequest, a jqXHR object will expose the following properties and methods:

readyState
responseXML and/or responseText when the underlying request responded with xml and/or text, respectively
status
statusText
abort( [ statusText ] )
getAllResponseHeaders() as a string
getResponseHeader( name )
overrideMimeType( mimeType )
setRequestHeader( name, value ) which departs from the standard by replacing the old value with the new one rather than concatenating the new value to the old one
statusCode( callbacksByStatusCode )
No onreadystatechange mechanism is provided, however, since done, fail, always, and statusCode cover all conceivable requirements.

As you can see there is no way to get hold of the response URL because the jqXHR API does not expose it