Perl Inserting string into a url at specific places - regex

Question

I have the following piece of code:
#!/usr/bin/perl
use strict;
use warnings;
#use diagnostics;
use URI qw( );
my #insert_words = qw(HELLO GOODBYE);
while (<DATA>) {
chomp;
my $url = URI->new($_);
my $query = $url->query;
foreach (#insert_words) {
# Use package vars to communicate with /(?{})/ blocks.
local our $insert_word = $_;
local our #queries;
if (defined $query) {
$query =~ m{
^(.*[/=])([^/=&]*)((?:[/=&].*)?)\z
(?{
if (length $2) {
push #queries, "$1$insert_word$2$3";
push #queries, "$1$insert_word$3";
push #queries, "$1$2$insert_word$3";
}
})
(?!)
}x;
}
if (#queries) {
for (#queries) {
$url->query($_);
print $url, "\n";
}
}
else {
print $url, "\n";
}
}
}
__DATA__
http://www.example.com/index.php?route=9&other=7
The above piece of code works correctly and produces the following output:
http://www.example.com/index.php?route=9&other=HELLO7
http://www.example.com/index.php?route=9&other=HELLO
http://www.example.com/index.php?route=9&other=7HELLO
http://www.example.com/index.php?route=HELLO9&other=7
http://www.example.com/index.php?route=HELLO&other=7
http://www.example.com/index.php?route=9HELLO&other=7
http://www.example.com/index.php?route=9&other=GOODBYE7
http://www.example.com/index.php?route=9&other=GOODBYE
http://www.example.com/index.php?route=9&other=7GOODBYE
http://www.example.com/index.php?route=GOODBYE9&other=7
http://www.example.com/index.php?route=GOODBYE&other=7
http://www.example.com/index.php?route=9GOODBYE&other=7
As you can see it inserts the words in the array at specific places in the url.
What I am now having problems with:
I would now like to add the functionality to do all the possible combinations of HELLO and GOODBYE (or whatever is in the #insert_words) as well, for example it should also add the following url's to the output I already get:
http://www.example.com/index.php?route=HELLO&other=GOODBYE
http://www.example.com/index.php?route=HELLO&other=HELLO
http://www.example.com/index.php?route=GOODBYE&other=HELLO
http://www.example.com/index.php?route=GOODBYE&other=GOODBYE
But I do not know how to go about this in the best way?
Your help with this will be much appreciated, many thanks

Answer 1

Please don't use fancy regexes like that - they are an experimental feature of Perl and are far from simple to comprehend.
If I understand you then you need to do this recursively.
I think you want all variations of the URL with each query parameter as it is, or preceded, succeeded, or replaced by every value in #insert_words.
This seems to do what you ask. It uses URI::QueryParam to split up the query portion of the URL properly instead of using your nasty regex. It does produce substantially more combinations than you show in your question but I can see no other way of interpreting your requirement.
The number of possible variations is 49. Each parameter can have its original value, or be preceded, succeeded or replaced by either of two values. That is seven possible values for each parameter and so 7² or 49 different variations for two parameters.
use strict;
use warnings;
use URI;
use URI::QueryParam;
my #insert_words = qw/ HELLO GOODBYE /;
my #urls;
sub mod_param {
my ($url, $paridx, #insertions) = #_;
my #params = $url->query_param;
return if $paridx > $#params;
my $key = $params[$paridx];
my $oldval = $url->query_param($key);
my #variations = ($oldval);
push #variations, ($oldval.$_, $_.$oldval, $_) for #insertions;
for my $val (#variations) {
$url->query_param($key, $val);
if ($paridx == $#params) {
push #urls, "$url";
}
else {
mod_param($url, $paridx + 1, #insertions);
}
}
$url->query_param($key, $oldval);
}
while (<DATA>) {
chomp;
my $url = URI->new($_);
#urls = ();
mod_param($url, 0, #insert_words);
print $_, "\n" for #urls;
}
__DATA__
http://www.example.com/index.php?route=9&other=7
output
http://www.example.com/index.php?route=9&other=7
http://www.example.com/index.php?route=9&other=7HELLO
http://www.example.com/index.php?route=9&other=HELLO7
http://www.example.com/index.php?route=9&other=HELLO
http://www.example.com/index.php?route=9&other=7GOODBYE
http://www.example.com/index.php?route=9&other=GOODBYE7
http://www.example.com/index.php?route=9&other=GOODBYE
http://www.example.com/index.php?route=9HELLO&other=7
http://www.example.com/index.php?route=9HELLO&other=7HELLO
http://www.example.com/index.php?route=9HELLO&other=HELLO7
http://www.example.com/index.php?route=9HELLO&other=HELLO
http://www.example.com/index.php?route=9HELLO&other=7GOODBYE
http://www.example.com/index.php?route=9HELLO&other=GOODBYE7
http://www.example.com/index.php?route=9HELLO&other=GOODBYE
http://www.example.com/index.php?route=HELLO9&other=7
http://www.example.com/index.php?route=HELLO9&other=7HELLO
http://www.example.com/index.php?route=HELLO9&other=HELLO7
http://www.example.com/index.php?route=HELLO9&other=HELLO
http://www.example.com/index.php?route=HELLO9&other=7GOODBYE
http://www.example.com/index.php?route=HELLO9&other=GOODBYE7
http://www.example.com/index.php?route=HELLO9&other=GOODBYE
http://www.example.com/index.php?route=HELLO&other=7
http://www.example.com/index.php?route=HELLO&other=7HELLO
http://www.example.com/index.php?route=HELLO&other=HELLO7
http://www.example.com/index.php?route=HELLO&other=HELLO
http://www.example.com/index.php?route=HELLO&other=7GOODBYE
http://www.example.com/index.php?route=HELLO&other=GOODBYE7
http://www.example.com/index.php?route=HELLO&other=GOODBYE
http://www.example.com/index.php?route=9GOODBYE&other=7
http://www.example.com/index.php?route=9GOODBYE&other=7HELLO
http://www.example.com/index.php?route=9GOODBYE&other=HELLO7
http://www.example.com/index.php?route=9GOODBYE&other=HELLO
http://www.example.com/index.php?route=9GOODBYE&other=7GOODBYE
http://www.example.com/index.php?route=9GOODBYE&other=GOODBYE7
http://www.example.com/index.php?route=9GOODBYE&other=GOODBYE
http://www.example.com/index.php?route=GOODBYE9&other=7
http://www.example.com/index.php?route=GOODBYE9&other=7HELLO
http://www.example.com/index.php?route=GOODBYE9&other=HELLO7
http://www.example.com/index.php?route=GOODBYE9&other=HELLO
http://www.example.com/index.php?route=GOODBYE9&other=7GOODBYE
http://www.example.com/index.php?route=GOODBYE9&other=GOODBYE7
http://www.example.com/index.php?route=GOODBYE9&other=GOODBYE
http://www.example.com/index.php?route=GOODBYE&other=7
http://www.example.com/index.php?route=GOODBYE&other=7HELLO
http://www.example.com/index.php?route=GOODBYE&other=HELLO7
http://www.example.com/index.php?route=GOODBYE&other=HELLO
http://www.example.com/index.php?route=GOODBYE&other=7GOODBYE
http://www.example.com/index.php?route=GOODBYE&other=GOODBYE7
http://www.example.com/index.php?route=GOODBYE&other=GOODBYE