js网络请求跨域问题汇总(携带cookie)

前端程序使用extjs写,在本地测试,发送请求到服务器时,发现存在跨域的问题,cookie也没有set成功,于是乎在这里整理一下解决过程

由于篇幅较长,不想看解决过程的可以翻到最后看总结
1.跨域允许
2.客户端无法携带跨域cookie
3.因为加了withCredentials报文头,可是客户端不知道服务器允不允许报的错
4.由于客户端不知道服务端是否允许POST请求而报的错

假设我的服务器IP是120.111.111.123

# 本地的html
# index.html

<html>
<head>
    <meta charset="utf8">
</head>
<body>
    <input type="button" onclick="request()" value="请求">
</body>
<script type="text/javascript" src="./ext-all.js"></script>
<script type="text/javascript">
    function request(){
        Ext.Ajax.request({
            url: 'http://120.111.111.123/setcookie.php',
            method: 'POST',
            params: { 
                'text': 'hello world'
            },
            success: function(transport){
                // do something
            },
            failure: function(transport){
                alert("Error: " - transport.responseText);
            }
        });
    }
    
</script>
</html>
#服务器的php文件
#path setcookie.php
<?php
session_start();
?>

点击“请求”按钮,发送请求后发现js报错

XMLHttpRequest cannot load http://120.111.111.123/setcookie.php. 
Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. 
Origin 'null' is therefore not allowed access.

报这个错就说明我们跨域了,不在允许的访问源,于是乎我在服务的setcookie.php加入header('Access-Control-Allow-Origin:*');允许所有源

<?php
session_start();
header('Access-Control-Allow-Origin:*'); 

// 功能...
// ...

然后又报错

XMLHttpRequest cannot load http://120.111.111.123/setcookie.php. Request header field X-Requested-With is not allowed by Access-Control-Allow-Headers in preflight response.

这次的报错是因为,在跨域的时候,extjs不会直接发post请求,而是先发送一个option请求,看看服务器允许什么访问头(比如是不是允许post请求),验证成功后才会发送真正的请求

#用谷歌的开发者工具抓的option报文
OPTIONS /setcookie.php HTTP/1.1
Host: 120.111.111.123
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
Access-Control-Request-Method: POST
Origin: null
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36
Access-Control-Request-Headers: x-requested-with
Accept: */*
Accept-Encoding: gzip, deflate, sdch
Accept-Language: zh-CN,zh;q=0.8

接下来,我们只要发送我们允许什么请求头就行了

#path /setcookie.php

session_start();
header('Access-Control-Allow-Origin:*'); 

header('Access-Control-Allow-Methods:OPTIONS, GET, POST'); // 允许option,get,post请求
header('Access-Control-Allow-Headers:x-requested-with'); // 允许x-requested-with请求头
header('Access-Control-Max-Age:86400'); // 允许访问的有效期

// 功能...
// ...

继续测试我们的新功能,成功的解决了跨域问题

1.png

but,cookie没有“设置成功”。而之所以没有“设置成功”,是因为cookie存在本地,但是每个cookie都有一个domain,当你本地的cookie中存在你当前访问的域时,才会被带过去,而我的index.html文件是本地访问的,即http://localhost/index.html,而cookie的域是120.111.111.123的,所以不行了。于是乎继续改

#path index.html
<html>
<head>
    <meta charset="utf8">
</head>
<body>
    <input type="button" onclick="request()" value="请求">
</body>
<script type="text/javascript" src="./ext-all.js"></script>
<script type="text/javascript">
    function request(){
        Ext.Ajax.request({
            url: 'http://120.111.111.123/setcookie.php',
            method: 'POST',
            params: { 
                'text': 'hello world'
            },
            withCredentials: true, # 加了这个
            success: function(transport){
                // do something
            },
            failure: function(transport){
                alert("Error: " - transport.responseText);
            }
        });
    }
    
</script>
</html>

继续访问,报错

XMLHttpRequest cannot load http://120.111.111.123/setcookie.php. 
Response to preflight request doesn't pass access control check: A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. 
Origin 'null' is therefore not allowed access. 
The credentials mode of an XMLHttpRequest is controlled by the withCredentials attribute.

现在这个错误产生的原因就是
1.因为加入了withCredentials之后,Access-Control-Allow-Origin就不能用“*”了,既然不允许访问这个源,那我就让你发个报文头让你允许访问呗!

<?php
#path setcookie.php
session_start();
// 是否存在请求源
if(isset($_SERVER["HTTP_ORIGIN"])) {
    header('Access-Control-Allow-Origin:'.$_SERVER["HTTP_ORIGIN"]);  
}

header('Access-Control-Allow-Methods:OPTIONS, GET, POST');
header('Access-Control-Allow-Headers:x-requested-with');
header('Access-Control-Max-Age:86400');

// 功能...
// ...

?>

好了,上传完代码,继续测试。发送请求之后,又报错了(这错中错,一个个坑搞的大家都看得不耐烦了吧,我保证,这是最后一个报错了)

XMLHttpRequest cannot load http://120.111.111.123/setcookie.php. 
Response to preflight request doesn't pass access control check: Credentials flag is 'true', but the 'Access-Control-Allow-Credentials' header is ''. 
It must be 'true' to allow credentials. Origin 'null' is therefore not allowed access.

大概的意思就是说我给你发了withCredentials报文头,但是你服务器没有跟我说允许我带这个报文头,那么解决方法就是加上允许发这个报文头的报文头

# path setcookie.php
<?php

session_start();
// 是否存在请求源
if(isset($_SERVER["HTTP_ORIGIN"])) {
    header('Access-Control-Allow-Origin:'.$_SERVER["HTTP_ORIGIN"]);  
}
header('Access-Control-Allow-Origin:null');  
header('Access-Control-Allow-Methods:OPTIONS, GET, POST');
header('Access-Control-Allow-Headers:x-requested-with');
header('Access-Control-Max-Age:86400');

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


// 功能...
// ...

?>

接下来进行最终的测试,biu~成功了,终于成功了!!!(0.0自己嗨起来了)

2.png

接下来总结一下,之所以跨域会引起那么多问题,都是因为耿直的客户端,发什么类型的请求都要服务器允许,而且要明文允许,允许的内容包括如下
1.跨域允许
解决方法:服务器发送允许客户端发送源的报文头
header('Access-Control-Allow-Origin:'.$_SERVER["HTTP_ORIGIN"]);

4.png

2.客户端无法携带跨域cookie
这个时候就可以在extjs中加入withCredentials

       Ext.Ajax.request({
            url: 'http://120.111.111.123/setcookie.php',
            method: 'POST',
            params: { 
                'text': 'hello world'
            },
            withCredentials: true,
            success: function(transport){
                // do something
            },
            failure: function(transport){
                alert("Error: " - transport.responseText);
            }
        });

3.因为加了withCredentials报文头,可是客户端不知道服务器允不允许报的错(耿直的客户端)
这个时候就在服务器发送Access-Control-Allow-Credentials

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

4.由于客户端不知道服务端是否允许POST请求而报的错
这个时候要在服务器端加入

header('Access-Control-Allow-Methods:OPTIONS, GET, POST');
header('Access-Control-Allow-Headers:x-requested-with');
header('Access-Control-Max-Age:86400');

以上汇总起来就是

header('Access-Control-Allow-Methods:OPTIONS, GET, POST');
header('Access-Control-Allow-Headers:x-requested-with');
header('Access-Control-Max-Age:86400');  
header('Access-Control-Allow-Origin:'.$_SERVER['HTTP_ORIGIN']);
header('Access-Control-Allow-Credentials:true');
header('Access-Control-Allow-Methods:GET, POST, PUT, DELETE, OPTIONS');
header('Access-Control-Allow-Headers:x-requested-with,content-type');
header('Access-Control-Allow-Headers:Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With');

代码已经放到github了,有啥问题欢迎大家指出

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