带有 JSON 响应的 Nginx 错误页面

Question

我正在尝试为在维护期间向我的应用程序提出请求的客户提供维护页面。以下是我为此目的的 nginx 配置。

server {
  recursive_error_pages on;
  listen 80;
   ...

  if (-f $document_root/maintenance.html) {
    return 503;
  }

  error_page 404 /404.html;
  error_page 500 502 504 /500.html;
  error_page 503 @503;

  location = /404.html {
    root $document_root;
  }
  location = /500.html {
    root $document_root;
  }
  location @503 {
    error_page 405 =/maintenance.html;
    if (-f $request_filename) {
      break;
    }
    rewrite ^(.*)$ /maintenance.html break;
  }
}

假设我通过创建$document_root/maintenance.html. 这个文件中，正确地，是当用户与请求服务Accept的报头text/html。

$ curl http://server.com/ -i -v -X GET -H "Accept: text/html"
* Adding handle: conn: 0xf89420
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0xf89420) send_pipe: 1, recv_pipe: 0
* About to connect() to server.com port 80 (#0)
*   Trying xxx.xxx.xxx.xxx...
* Connected to server.com (xxx.xxx.xxx.xxx) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.33.0
> Host: server.com
> Accept: text/html
> 
< HTTP/1.1 503 Service Temporarily Unavailable
HTTP/1.1 503 Service Temporarily Unavailable
* Server nginx/1.1.19 is not blacklisted
< Server: nginx/1.1.19
Server: nginx/1.1.19
< Date: Thu, 14 Nov 2013 11:16:16 GMT
Date: Thu, 14 Nov 2013 11:16:16 GMT
< Content-Type: text/html
Content-Type: text/html
< Content-Length: 27
Content-Length: 27
< Connection: keep-alive
Connection: keep-alive

< 
This is under maintenance.
* Connection #0 to host server.com left intact

现在一些客户端将Acceptheader设置为application/json. 我如何向他们发送 JSON 响应而不是maintenance.html？

以下是我在设置Accept为application/json.

$ curl http://server.com/ -i -v -X GET -H "Accept: application/json"
* Adding handle: conn: 0x190c430
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x190c430) send_pipe: 1, recv_pipe: 0
* About to connect() to server.com port 80 (#0)
*   Trying xxx.xxx.xxx.xxx...
* Connected to server.com (xxx.xxx.xxx.xxx) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.33.0
> Host: server.com
> Accept: application/json
> 
< HTTP/1.1 503 Service Temporarily Unavailable
HTTP/1.1 503 Service Temporarily Unavailable
* Server nginx/1.1.19 is not blacklisted
< Server: nginx/1.1.19
Server: nginx/1.1.19
< Date: Thu, 14 Nov 2013 11:15:50 GMT
Date: Thu, 14 Nov 2013 11:15:50 GMT
< Content-Type: text/html
Content-Type: text/html
< Content-Length: 27
Content-Length: 27
< Connection: keep-alive
Connection: keep-alive

< 
This is under maintenance.
* Connection #0 to host server.com left intact

Answer 1

尝试使用地图

map $http_accept $maintenance_page {
    default /maintenance.html;
    ~application/json /maintenance.json;
}

然后将 /maintenance.html 替换为 $maintenance_page

有关http://nginx.org/en/docs/http/ngx_http_map_module.html的更多详细信息