inline C-Code

[Sascha Ottolski]

Hi,

in one or the other presentation slide is a small example about inline 
C-Code; and there is a commit that only says "undocmented and 
unsupported" (http://varnish.projects.linpro.no/changeset/1301).

Now I'm wondering, is there anyway at list ab bit of documentation 
somewhere, or could someone post some examples to the list? (may be a 
searchable archive of this list would reveal some?)

Basically, I want to do a bit of calculation with the help of a 
(pseudo-)encrypted URL and the current time (which seems to be 
available as the "new" keyword), to decide if the request should be 
served, and if so, create the real URL that is to be send to the 
backend, and a hashkey.

So probably I need something like the following seudo-code (my C 
knowledge is kinda limited :-():

sub vcl_recv {
    if (req.url ~ "/enc-prefix/") {
        C{
            timestamp, real_url = decrypt(req.url);

            // valid for two hours
            if not (now + 2h < timestamp < now) {
                error XXX "page expired";
            }

            req.url = real_url;

        }C

        lookup;
    }
}


So  I guess the main questions are:

- how to access existing vcl names/variables

- how to set existing vcl names/variables

- what if I need access to external C libraries, i.e. to use a 
custom "decrypt" function?


Any pointers greatly appreciated,

Sascha