如何在 Nginx 代理服务器中启用 CORS？

Question

正如我的标题，这是位于 conf.d/api-server.conf 中的配置文件

server {
  listen 80;
  server_name api.localhost;

  location / {
    add_header 'Access-Control-Allow-Origin' 'http://api.localhost';
    add_header 'Access-Control-Allow_Credentials' 'true';
    add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
    add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

    if ($request_method = 'OPTIONS') {
      add_header 'Access-Control-Max-Age' 1728000;
      add_header 'Content-Type' 'text/plain charset=UTF-8';
      add_header 'Content-Length' 0;
      return 204;
    }

    proxy_redirect off;
    proxy_set_header host $host;
    proxy_set_header X-real-ip $remote_addr;
    proxy_set_header X-forward-for $proxy_add_x_forwarded_for;
    proxy_pass http://127.0.0.1:3000;
  }
}

nginx.conf 文件保持默认不变。

向 api.localhost (api.localhost/admin/login) 发送请求后，仍然收到 405 错误：

XMLHttpRequest cannot load http://api.localhost/admin/login. Response 
to preflight request doesn't pass access control check: No 'Access-
Control-Allow-Origin' header is present on the requested resource. 
Origin 'http://admin.localhost:3000' is therefore not allowed access. 
The response had HTTP status code 405.

Answer 1

问题是您的 if 条件不会在 / 中发送父级中的标头。如果您检查预检响应标头，它将是

HTTP/1.1 204 No Content
Server: nginx/1.13.3
Date: Fri, 01 Sep 2017 05:24:04 GMT
Connection: keep-alive
Access-Control-Max-Age: 1728000
Content-Type: text/plain charset=UTF-8
Content-Length: 0

这并没有带来任何好处。所以有两个可能的解决方法。复制 add_header 里面的 if 块也

server {
  listen 80;
  server_name api.localhost;

  location / {
    add_header 'Access-Control-Allow-Origin' 'http://api.localhost';
    add_header 'Access-Control-Allow-Credentials' 'true';
    add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
    add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

    if ($request_method = 'OPTIONS') {
      add_header 'Access-Control-Allow-Origin' 'http://api.localhost';
      add_header 'Access-Control-Allow-Credentials' 'true';
      add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
      add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';
      add_header 'Access-Control-Max-Age' 1728000;
      add_header 'Content-Type' 'text/plain charset=UTF-8';
      add_header 'Content-Length' 0;
      return 204;
    }

    proxy_redirect off;
    proxy_set_header host $host;
    proxy_set_header X-real-ip $remote_addr;
    proxy_set_header X-forward-for $proxy_add_x_forwarded_for;
    proxy_pass http://127.0.0.1:3000;
  }
}

或者你可以把它移到位置块之外，这样每个请求都有响应

server {
   listen 80;
   server_name api.localhost;

   add_header 'Access-Control-Allow-Origin' 'http://api.localhost';
   add_header 'Access-Control-Allow-Credentials' 'true';
   add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
   add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

  location / {

    if ($request_method = 'OPTIONS') {
      add_header 'Access-Control-Max-Age' 1728000;
      add_header 'Content-Type' 'text/plain charset=UTF-8';
      add_header 'Content-Length' 0;
      return 204;
    }

    proxy_redirect off;
    proxy_set_header host $host;
    proxy_set_header X-real-ip $remote_addr;
    proxy_set_header X-forward-for $proxy_add_x_forwarded_for;
    proxy_pass http://127.0.0.1:3000;
  }
}

如果您只想在 CORS 配置中允许某些位置。像/api 那么你应该用你的标题创建一个模板conf

 add_header 'Access-Control-Allow-Origin' 'http://api.localhost';
 add_header 'Access-Control-Allow-Credentials' 'true';
 add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
 add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

然后使用

include conf.d/corsheaders.conf;

在您的 OPTIONS 块和 /api 块中。所以 CORS 只允许用于/api。如果您不关心 CORS 的位置，那么您可以使用第二种方法将核心标头移动到服务器块