Beginner question:Nginx request_uri meaning ?

[Maxim Dounin]

Hello!

On Wed, Jan 11, 2017 at 05:18:26PM +0100, Bike dernikov1 wrote:

> Hi, i have "simple" question, need simple explanation. It's driving me
> nuts.
> 
> In nginx configuration what is meaning of  $request_uri in line?
> 
> *********************************************************
> return 301 $scheme://example.com1$request_uri;
> ***********************************************************
> In documentation  write: $request_uri is full  request URI.
> I will try to describe my doubth.
> 
> Simple request URL: http://www.example.com/index.html
> 
> Full request URI is the same: http://example.com/index.html
> 
> $request_uri=http://example.com/index.html.
> 
> As i understand then line:
> 
>  return 301 $scheme://example1.com$request_uri;
> 
> must return:
> 
> http://example1.comhttp://example.com/index.html.
> 
> But that  cannot be correct.
> 
> So what mean var $request_uri ? Is defined wrong in documentation. (or URI
> is not what i described ?) or it mean something different, or it mean
> something different in combination with return ??
> Thanks for help.

The term "request URI" as used in the nginx documentation in many 
places, as well as in various variables, dates back to the 
original and most common HTTP meaning - the URI form as used 
identify a resource on a server.

Quoting https://tools.ietf.org/html/rfc1945#section-5.1.2:

   The most common form of Request-URI is that used to identify a
   resource on an origin server or gateway. In this case, only the
   absolute path of the URI is transmitted (see Section 3.2.1,
   abs_path). For example, a client wishing to retrieve the resource
   above directly from the origin server would create a TCP connection
   to port 80 of the host "www.w3.org" and send the line:

       GET /pub/WWW/TheProject.html HTTP/1.0

   followed by the remainder of the Full-Request. Note that the absolute
   path cannot be empty; if none is present in the original URI, it must
   be given as "/" (the server root).

At the HTTP/1.0 time this was the only allowed form in requests to 
origin servers (absolute form was only allowed in requests to a 
proxy).

With HTTP/1.1 absolute form can be also used in normal 
requests, but it's not something actually used in practice, and 
also not something various configurations and software can cope 
with.  So even if a request uses the absolute form of the request 
URI, nginx provides $request_uri as if it was given in the 
abs_path form.

-- 
Maxim Dounin
http://nginx.org/