问题背景
这两天遇到一个这样的需求:
有两个项目a和b,在a项目中有页面需要调用b中的接口,两项目的域名不同,分别为a.com, b.com。这时候如果直接调用,显然跨域了。一番折腾之后,问题解决了,这里记录一下解决方法。
解决方法
第一步,解决跨域
这个使用Nginx的代理功能即可,在a服务器的Nginx添加如下示例配置:
location ~ /xxx/ {
proxy_pass http://b.com;
}
这样就把路径中带有/xxx/的请求都转到了b.com。如果不需要保存cookie,保持session这样的功能,这样就可以了。
然而,本项目就是要用到cookie,所以就有了下边的内容。
第二步,设置domain
因为cookie当中是有domain的,两个服务器的一般不同,比如a服务器返回的Response Headers中是
Set-Cookie:JSESSIONID=_3y4u02v4cbpBw10DoCrMSnjg7m34xuum1XRWBF1Uno; path=/; domain=a.com
而b服务器返回的是
Set-Cookie:JSESSIONID=_3y4u02v4cbpBw10DoCrMSnjg7m34xuum1XRWBF1Uno; path=/; domain=b.com
这时候如果a项目的页面调用了b的接口,浏览器发现接口返回的domain不是a.com,就不会把cookie保存起来,session也就失效了。Nginx 引入了proxy_cookie_domain来解决这个问题。示例:
location ~ /xxx/ {
proxy_cookie_domain b.com a.com;
proxy_pass http://b.com;
}
这样就可以在Nginx转接请求的时候自动把domain中的b.com 转换成 a.com,这样cookie就可以设置成功了。
但是,对于有些情况这样转换不灵光。比如,b项目的domain是.b.com,前边多了一个小点,那对应的改为 proxy_cookie_domain .b.com a.com; 可以不?通过实践,不行!!!
通过查看Nginx文档,找到了解决办法。其实,除了上边那种配置方式外,Nginx还支持正则配置:
location ~ /xxx/ {
proxy_cookie_domain ~\.?b.com a.com;
proxy_pass http://b.com;
}
这样就可以把domain中的.b.com 转换成 a.com啦。
第三步,设置path
正常情况下完成以上两步就可以了,因为cookie中的path一般默认的是path=/,也就是所有请求都可以访问本cookie。但有些服务器会指定,只允许某个层级下的请求可以访问cookie,比如:
Set-Cookie:JSESSIONID=_3y4u02v4cbpBw10DoCrMSnjg7m34xuum1XRWBF1Uno; path=/sub/; domain=b.com
这样就只允许相对根路径,以/sub/开头的请求路径才能访问cookie。这时候就又可能出现cookie无效的问题了,为了解决这个问题,可以使用proxy_cookie_path。示例:
location ~ /xxx/ {
proxy_cookie_domain ~\.?b.com a.com;
proxy_cookie_path /sub/ /;
proxy_pass http://b.com;
}
这样就把只允许/sub/层级下的请求访问cookie,改为允许所有请求访问cookie了。
总结
折腾了几个小时,还是在Nginx官方文档找到了解决方案。说了这么多,其实只要这样简单的几行配置就可以搞定跨域cookie了。希望本文能够对你有所帮助。
备注
Nginx文档节选内容:
Syntax: proxy_cookie_domain off;
proxy_cookie_domain domain replacement;
Default:
proxy_cookie_domain off;
Context: http, server, location
This directive appeared in version 1.1.15.
Sets a text that should be changed in the domain attribute of the “Set-Cookie” header fields of a proxied server response. Suppose a proxied server returned the “Set-Cookie” header field with the attribute “domain=localhost”. The directive
proxy_cookie_domain localhost example.org;
will rewrite this attribute to domain=example.org.
A dot at the beginning of the domain and replacement strings and the domain attribute is ignored. Matching is case-insensitive.
The domain and replacement strings can contain variables:
proxy_cookie_domain www.$host $host;
The directive can also be specified using regular expressions. In this case, domain should start from the “~” symbol. A regular expression can contain named and positional captures, and replacement can reference them:
proxy_cookie_domain ~.(?P-0-9a-z+.a-z+)$ $sl_domain;
There could be several proxy_cookie_domain directives:
proxy_cookie_domain localhost example.org;
proxy_cookie_domain ~.(a-z+.a-z+)$ $1;
The off parameter cancels the effect of all proxy_cookie_domain directives on the current level:
proxy_cookie_domain off;
proxy_cookie_domain localhost example.org;
proxy_cookie_domain www.example.org example.org;
proxy_cookie_path off;
proxy_cookie_path path replacement;
Default:
proxy_cookie_path off;
Context: http, server, location
This directive appeared in version 1.1.15.
Sets a text that should be changed in the path attribute of the “Set-Cookie” header fields of a proxied server response. Suppose a proxied server returned the “Set-Cookie” header field with the attribute “path=/two/some/uri/”. The directive
proxy_cookie_path /two/ /;
will rewrite this attribute to “path=/some/uri/”.
The path and replacement strings can contain variables:
proxy_cookie_path $uri /some$uri;
The directive can also be specified using regular expressions. In this case, path should either start from the “~” symbol for a case-sensitive matching, or from the “~*” symbols for case-insensitive matching. The regular expression can contain named and positional captures, and replacement can reference them:
proxy_cookie_path ~*^/user/(^/+) /u/$1;
There could be several proxy_cookie_path directives:
proxy_cookie_path /one/ /;
proxy_cookie_path / /two/;
The off parameter cancels the effect of all proxy_cookie_path directives on the current level:
proxy_cookie_path off;
proxy_cookie_path /two/ /;
proxy_cookie_path ~*^/user/(^/+) /u/$1;
参考文档:https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cookie_domain
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