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real language
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Language VCL
(Varnish Configuration Language)
| Date: | 05/21/12 |
| Author: | Jarek Ratajski |
| URL: | n/a |
| Comments: | 0 |
| Info: | https://www.varnish-cache.org/ |
| Score: |  (3.25 in 4 votes) |
####################################################################
# 99 bottles of beer song in VCL (Varnish Configuration language)
# Visit: https://www.varnish-cache.org/docs/3.0/reference/vcl.html#varnish-configuration-language
# Varnish is an HTTP accelerator with simple configuration language.
# Normally varnish acts as a Proxy and forwards requests to defined backends (HTTP Servers).
# However it is possible to make a http loop and force it to pass processing to self -
# defining backend on same url as varnish.
# With possiblity to display error page we can create a nice 99 beers page as an output.
# usage: store this file as /etc/varnish/99.vcl
# run varnish: varnishd -f /etc/varnish/99.vcl -p thread_pool_min=200
# Last parameter is very important (otherwise varnish will hang on recursive calls).
# enter in web browser
# http://localhost/sing99
#
# Author: Jarek Ratajski
#####################################################################
backend self {
.host = "127.0.0.1";
.port = "80";
.connect_timeout = 40s;
.first_byte_timeout = 60s;
.between_bytes_timeout = 60s;
.max_connections = 200;
}
####################################################################
# vcl_recv
####################################################################
sub vcl_recv {
if (req.url ~ "/verse" ) {
if (req.http.bottles ) {
if ( req.http.bottles == "0" ) {
error 200 "alles OK";
return (error);
} else {
call dec_bottles;
set req.http.bottlestext = req.http.bottlestext + " " + req.http.bottles + "b" ;
unset req.http.X-Varnish;
set req.backend = self;
set req.url = "/verse" + req.http.bottles;
return (pass);
}
}
}
else if (req.url == "/sing99") {
set req.http.bottles = "99";
set req.http.bottlestext = req.http.bottles+ "b";
set req.backend = self;
set req.url = "/verse99";
return (pass);
} else {
#fallback
set req.url = "/sing99";
set req.backend = self;
return (pass);
}
}
#very basic decrement function (one digit)
#varnish does not offer arithmetic operators
sub dec_digit {
if ( req.http.bdigit == "0" ) {
set req.http.bdigit = "9";
#this is infamous carry flag used when substracting 2 digit numbers
set req.http.carry = "yes";
}
if ( req.http.bdigit == "1" ) {
set req.http.bdigit = "0";
}
if ( req.http.bdigit == "2" ) {
set req.http.bdigit = "1";
}
if ( req.http.bdigit == "3" ) {
set req.http.bdigit = "2";
}
if ( req.http.bdigit == "4" ) {
set req.http.bdigit = "3";
}
if ( req.http.bdigit == "5" ) {
set req.http.bdigit = "4";
}
if ( req.http.bdigit == "6" ) {
set req.http.bdigit = "5";
}
if ( req.http.bdigit == "7" ) {
set req.http.bdigit = "6";
}
if ( req.http.bdigit == "8" ) {
set req.http.bdigit = "7";
}
if ( req.http.bdigit == "9" ) {
set req.http.bdigit = "8";
}
}
#decrement one or two digit number
sub dec_bottles {
if ( req.http.bottles ~ "\d\d" ) {
set req.http.bdigit = regsub(req.http.bottles, "\d(\d)", "\1");
call dec_digit;
set req.http.first_digit = req.http.bdigit;
set req.http.bdigit = regsub(req.http.bottles, "(\d)\d", "\1");
if ( req.http.carry=="yes" ) {
set req.http.carry="no";
call dec_digit;
if ( req.http.bdigit=="0" ) {
set req.http.bdigit = "";
}
}
set req.http.bottles = req.http.bdigit + req.http.first_digit;
} else {
set req.http.bdigit = req.http.bottles;
call dec_digit;
set req.http.bottles = req.http.bdigit;
}
}
####################################################################
# vcl_pipe
# all subsequent functions are left with default implementation
####################################################################
sub vcl_pipe {
return (pipe);
}
####################################################################
# vcl_hash
####################################################################
sub vcl_hash {
hash_data(req.url);
return (hash);
}
####################################################################
# vcl_hit
####################################################################
sub vcl_hit {
return (deliver);
}
####################################################################
# vcl_miss
####################################################################
sub vcl_miss {
return (fetch);
}
####################################################################
# vcl_fetch
####################################################################
sub vcl_fetch {
return (deliver);
}
####################################################################
# vcl_deliver
####################################################################
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
return (deliver);
}
####################################################################
# vcl_error
####################################################################
sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
#there is a limitation of 4096 bytes for request header line
#this is why we use regexp at the end - and are not building complete song on the fly
set req.http.bottlestext = regsub(req.http.bottlestext, "(99)b", "<p>\1 bottles of beer on"
+ " the wall, \1 bottles of beer.<br>");
set req.http.bottlestext = regsub(req.http.bottlestext,"(\s1)b", "Take one down and pass it "
+ "around, \1 bottle of beer on the wall.</p><p>\1 bottle of beer on the wall, "
+ "\1 bottle of beer.<br>");
set req.http.bottlestext = regsub(req.http.bottlestext, "\s0b", "Take one down and pass it "
+ "around, no more bottles of beer on the wall.</p><p>No more bottles of beer on the wall, "
+ "no more bottles of beer. <br/> Go to the store and buy some more, "
+ "99 bottles of beer on the wall.</p>");
synthetic {"
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>"} + " 99 bottles of beer song " + {"</title>
</head>
<body>
"} + regsuball(req.http.bottlestext,"(\d\d?)b", "Take one down and pass it around, "
+"\1 bottles of beer on the wall.</p><p>\1 bottles of beer on the wall, "
+"\1 bottles of beer.<br>") + {"</p>
</body>
</html>
"};
return (deliver);
}
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