关于ajax跨域访问cookie丢失的解决方法的讲解

来源：五一七教育网

ajax跨域访问，可以使用jsonp方法或设置Access-Control-Allow-Origin实现，关于设置Access-Control-Allow-Origin实现跨域访问可以参考之前我写的文章《ajax 设置Access-Control-Allow-Origin实现跨域访问》

1.ajax跨域访问,cookie丢失

首先创建两个测试域名
a.fdipzone.com 作为客户端域名
b.fdipzone.com 作为服务端域名

测试代码

setcookie.php 用于设置服务端cookie

<?phpsetcookie('data', time(), time()+3600);?>

server.php 用于被客户端请求

<?php$name = isset($_POST['name'])? $_POST['name'] : '';$ret = array( 'success' => true, 'name' => $name, 'cookie' => isset($_COOKIE['data'])? $_COOKIE['data'] : '');// 指定允许其他域名访问header('Access-Control-Allow-Origin:http://a.fdipzone.com');// 响应类型header('Access-Control-Allow-Methods:POST'); 

// 响应头设置header('Access-Control-Allow-Headers:x-requested-with,content-type');

header('content-type:application/json');echo json_encode($ret);?>

test.html 客户端请求页面

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html>
 <head>
 <meta http-equiv="content-type" content="text/html;charset=utf-8">
 <script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
 <title> ajax 跨域访问cookie丢失的解决方法 </title>
 </head>

 <body>
 <script type="text/javascript">
 $(function(){

 $.ajax({
 url: 'http://b.fdipzone.com/server.php', // 跨域
 dataType: 'json',
 type: 'post',
 data: {'name':'fdipzone'},
 success:function(ret){
 if(ret['success']==true){
 alert('cookie:' + ret['cookie']);
 }
 }
 });

 }) </script>

 </body></html>

首先先执行http://b.fdipzone.com/setcookie.php, 创建服务端cookie。
然后执行http://a.fdipzone.com/test.html

输出

{"success":true,"name":"fdipzone","cookie":""}

获取cookie失败。

2.解决方法

客户端
请求时将withCredentials属性设置为true
使可以指定某个请求应该发送凭据。如果服务器接收带凭据的请求，会用下面的HTTP头部来响应。

服务端
设置header

header("Access-Control-Allow-Credentials:true");

允许请求带有验证信息
test.html 修改如下

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html>
 <head>
 <meta http-equiv="content-type" content="text/html;charset=utf-8">
 <script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
 <title> ajax 跨域访问cookie丢失的解决方法 </title>
 </head>

 <body>
 <script type="text/javascript">
 $(function(){

 $.ajax({
 url: 'http://b.fdipzone.com/server.php', // 跨域
 xhrFields:{withCredentials: true}, // 发送凭据
 dataType: 'json',
 type: 'post',
 data: {'name':'fdipzone'},
 success:function(ret){
 if(ret['success']==true){
 alert('cookie:' + ret['cookie']);
 }
 }
 });

 }) </script>

 </body></html>

server.php 修改如下

<?php$name = isset($_POST['name'])? $_POST['name'] : '';$ret = array( 'success' => true, 'name' => $name, 'cookie' => isset($_COOKIE['data'])? $_COOKIE['data'] : '');// 指定允许其他域名访问header('Access-Control-Allow-Origin:http://a.fdipzone.com');// 响应类型header('Access-Control-Allow-Methods:POST'); 

// 响应头设置header('Access-Control-Allow-Headers:x-requested-with,content-type');// 是否允许请求带有验证信息header('Access-Control-Allow-Credentials:true');

header('content-type:application/json');echo json_encode($ret);?>

按之前步骤执行，请求返回

{"success":true,"name":"fdipzone","cookie":"1484558863"}

获取cookie成功

3.注意事项

1.如果客户端设置了withCredentials属性设置为true，而服务端没有设置Access-Control-Allow-Credentials:true，请求时会返回错误。

XMLHttpRequest cannot load http://b.fdipzone.com/server.php. Credentials flag is 'true', but the 'Access-Control-Allow-Credentials' header is ''. It must be 'true' to allow credentials. Origin 'http://a.fdipzone.com' is therefore not allowed access.

2.服务端header设置Access-Control-Allow-Credentials:true后，Access-Control-Allow-Origin不可以设为*，必须设置为一个域名，否则回返回错误。

XMLHttpRequest cannot load http://b.fdipzone.com/server.php. A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. Origin 'http://a.fdipzone.com' is therefore not allowed access. The credentials mode of an XMLHttpRequest is controlled by the withCredentials attribute.

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