Really logging the POST request body (instead of “-”) with nginx

Question

I\'m trying to log POST body, and add $request_body to the log_format in http clause, but the access_log command just pri

Answer 1

Nginx doesn't parse the client request body unless it really needs to, so it usually does not fill the $request_body variable.

The exceptions are when:

• it sends the request to a proxy,
• or a fastcgi server.

So you really need to either add the proxy_pass or fastcgi_pass directives to your block.

The easiest way is to send it to Nginx itself as a proxied server, for example with this configuration:

location = /c.gif {  
    access_log logs/uaa_access.log client;
    # add the proper port or IP address if Nginx is not on 127.0.0.1:80
    proxy_pass http://127.0.0.1/post_gif; 
}
location = /post_gif {
    # turn off logging here to avoid double logging
    access_log off;
    empty_gif;  
}

If you only expect to receive some key-pair values, it might be a good idea to limit the request body size:

client_max_body_size 1k;
client_body_buffer_size 1k;
client_body_in_single_buffer on;

I also received "405 Not Allowed" errors when testing using empty_gif; and curl (it was ok from the browser), I switched it to return 200; to properly test with curl.