Re: SCGI + Quixote, Location / ?

Michael Best wrote:

> Redirect isn't going to do anything in my case I already have a 
> trailing slash.  I'm going to http://www.example.com/ in my browser.
>
> <VirtualHost www.example.com:80>
> SCGIMount / localhost:4000
> <Location />
>   Order allow,deny
>   Allow from all
> </Location>
> </VirtualHost>
>
> Traceback contains:
> PATH_INFO
> QUERY_STRING
> REQUEST_URI     /
> SCGI            1
> SCRIPT_NAME     /
> SCRIPT_URI      http://www.example.com/
> SCRIPT_URL      /
>
> Doesn't this piece of code from mod_scgi.c tell the story though? 
> SCRIPT_NAME is set to r->uri when there isn't r->path_info.  Perhaps 
> something like if (PATH_INFO="" and REQUEST_URI="/") then 
> SCRIPT_NAME=""?  It's late and I just making a stab in the dark.
>
> And isn't the second add_header(t, "SCRIPT_NAME", r->uri); in the else 
> redundant, since it gets set before the if and gets set in the else so 
> it happens either way?
>
>     add_header(t, "SCRIPT_NAME", r->uri);
>     if (r->path_info) {
>         int path_info_start = find_path_info(r->uri, r->path_info);
>         add_header(t, "SCRIPT_NAME", apr_pstrndup(r->pool, r->uri,
>                                                   path_info_start));
>         add_header(t, "PATH_INFO", r->path_info);
>     }
>     else {
>         /* skip PATH_INFO, don't know it */
>         add_header(t, "SCRIPT_NAME", r->uri);
>     }
>
> Here is a discussion about something similar on the Web-SIG mailing 
> list in a thread titled WSGI tests:
> http://mail.python.org/pipermail/web-sig/2004-September/000925.html
>
> Looking in Python Web Server Gateway Interface v1.0 doesn't give me 
> much info either.
> http://www.python.org/peps/pep-0333.html



I guess SCGIMount '/' is a special case.   With my subdirectory example, 
the mount point is the *parent* of the root URL (=application home 
page).  It's in a never-never land where neither Apache nor Quixote can 
handle it, hence the need for the redirect.  But with "SCGIMount '/'", 
the mount point *is* the root URL, and there is no parent.  "SCGIMount 
''" looks invalid but there doesn't seem to be any other way, especially 
since Ian's WEB-Sig message suggests it should translate to:
    SCRIPT_NAME=""  PATH_INFO="/"
which would be consistent with how Quixote normally traverses the path.

So the question is whether users should put "SCGIMount ''" literally in 
their configs, or mod_scgi should implicitly convert it.  Either way is 
problematic:

SCGIMount '':  the URI between this and the corresponding <Location> is 
no longer identical, which makes it slightly more difficult to verify 
they are correct.  <Location> is needed because some directives cannot 
be outside it, and to make it easier to move an application between 
different mount points.

SCGIMount '/': the user has to remember this is a special case, 
otherwise they'll do "SCGIMount '/foo/'" for subdirectories.  Of course, 
it's arbitrary which convention we follow, as long as it's consistent 
with <Location> and doesn't leave a slashless URI in never-never land.


>> SCRIPT_NAME
>>     The initial portion of the request URL's "path" that corresponds 
>> to the application object, so that the application knows its virtual 
>> "location". This may be an empty string, if the application 
>> corresponds to the "root" of the server.
>> PATH_INFO
>>     The remainder of the request URL's "path", designating the 
>> virtual "location" of the request's target within the application. 
>> This may be an empty string, if the request URL targets the 
>> application root and does not have a trailing slash.
>

This rule for SCRIPT_NAME is consistent with the above.  The part about 
PATH_INFO being blank sounds like an error; it should be translated to 
'/'.  But "somebody" really has to send a redirect rather than just 
converting the value; otherwise the base URL will be wrong for relative 
HREFs within the document.