proxy_pass

Sets the protocol and address of a proxied server and an optional URI to which a location should be mapped. As a protocol, “http” or “https” can be specified. The address can be specified as a domain name or IP address, and an optional port:

proxy_pass http://localhost:8000/uri/;

or as a UNIX-domain socket path specified after the word “unix” and enclosed in colons:

proxy_pass http://unix:/tmp/backend.socket:/uri/;

If a domain name resolves to several addresses, all of them will be used in a round-robin fashion. In addition, an address can be specified as a server group.

A request URI is passed to the server as follows:

• If the proxy_pass directive is specified with a URI, then when a request is passed to the server, the part of a normalized request URI matching the location is replaced by a URI specified in the directive:

  location /name/ {
      proxy_pass http://127.0.0.1/remote/;
  }
  

• If proxy_pass is specified without a URI, the request URI is passed to the server in the same form as sent by a client when the original request is processed, or the full normalized request URI is passed when processing the changed URI:

  location /some/path/ {
      proxy_pass http://127.0.0.1;
  }
  

  Before version 1.1.12, if proxy_pass is specified without a URI, the original request URI might be passed instead of the changed URI in some cases.

In some cases, the part of a request URI to be replaced cannot be determined:

• When location is specified using a regular expression.

  In this case, the directive should be specified without a URI.

• When the URI is changed inside a proxied location using the rewrite directive, and this same configuration will be used to process a request (break):

  location /name/ {
      rewrite    /name/([^/]+) /users?name=$1 break;
      proxy_pass http://127.0.0.1;
  }
  

  In this case, the URI specified in the directive is ignored and the full changed request URI is passed to the server.

A server name, its port and the passed URI can also be specified using variables:

proxy_pass http://$host$uri;

or even like this:

proxy_pass $request;

In this case, the server name is searched among the described server groups, and, if not found, is determined using a resolver.

WebSocket proxying requires special configuration and is supported since version 1.3.13.