什么是跨域

当一个请求url的协议、域名、端口三者之间任意一个与当前页面url不同即为跨域

nginx解决跨域请求

nginx.config配置

server {listen       80;server_name  my.cn.com;location / {proxy_pass  http://test.cn.com:8081/test;index  index.html index.htm;}location /A {proxy_pass  http://a.a.com:8082/A;index  index.html index.htm;}location /B {proxy_pass  http://b.b.com:8083/B;ndex  index.html index.htm;}}

当浏览器访问：my.cn.com:80 nginx会转发到 http://test.cn.com:8081/test;
当浏览器访问：my.cn.com:80/A nginx会转发到 http://a.a.com:8082/A;
当浏览器访问：my.cn.com:80/B nginx会转发到 http://b.b.com:8083/B;

这种nginx解决方案跟springCloud中的zuul(网关)一样。根据 location /*** 转发至不同的请求去。

更多详细localtion的正则匹配规则可参考：nginx配置location总结及rewrite规则写法

网上还有另外一种nginx解决跨域请求的方案：

此方案未验证。。。。。

在nginx.conf中启用COSR的参考配置：

#
# Wide-open CORS config for nginx
#
location / {if ($request_method = 'OPTIONS') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';## Custom headers and headers various browsers *should* be OK with but aren't#add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';## Tell client that this pre-flight info is valid for 20 days#add_header 'Access-Control-Max-Age' 1728000;add_header 'Content-Type' 'text/plain charset=UTF-8';add_header 'Content-Length' 0;return 204;}if ($request_method = 'POST') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';}if ($request_method = 'GET') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type';}
}

这样就可以实现GET,POST,OPTIONS的跨域请求的支持
也可以 add_header Access-Control-Allow-Origin http://test.51testing.com; --指定允许的url;

其余解决跨域问题的手段有：