/ 
URL-Normalize-0.41
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/ URL::Normalize

NAME

URL::Normalize - Normalize/optimize URLs.

VERSION

Version 0.41

SYNOPSIS

use URL::Normalize;

my $normalizer = URL::Normalize->new( 'http://www.example.com/display?lang=en&article=fred' );

# Normalize the URL
$normalizer->make_canonical;
$normalizer->remove_directory_index;
$normalizer->remove_empty_query;

# Get the normalized version back
my $url = $normalizer->url;

DESCRIPTION

When writing a web crawler, for example, it's always very costly to check if a URL has been fetched/seen when you have millions or billions of URLs in a database.

This module can help you create a unique "ID" of a URL, which you can use as a key in a key/value-store; the key is the normalized URL, whereas all the URLs that refers to the normalized URL are part of the value (normally an array or hash);

'http://www.example.com/' = {
    'http://www.example.com:80/'        => 1,
    'http://www.example.com/index.html' => 1,
    'http://www.example.com/?'          => 1,
}

Above, all the URLs inside the hash normalizes to the key if you run these methods:

  • make_canonical

  • remove_directory_index

  • remove_empty_query

This is NOT a perfect solution.

If you normalize a URL using all the methods in this module, there is a high probability that the URL will stop "working." This is merely a helper module for those of you who wants to either normalize a URL using only a few of the safer methods, and/or for those of you who wants to generate a possibly unique "ID" from any given URL.

CONSTRUCTORS

new( $url )

Constructs a new URL::Normalize object:

my $normalizer = URL::Normalize->new( 'http://www.example.com/some/path' );

You can also send in just the path:

my $normalizer = URL::Normalize->new( '/some/path' );

The latter is NOT recommended, though, and hasn't been tested properly. You should always give URL::Normalize an absolute URL by using URI's new_abs.

METHODS

url

Get the current URL, preferably after you have run one or more of the normalization methods.

URI

Returns a URI representation of the current URL.

make_canonical

Just a shortcut for URI::URL->new->canonical->as_string, and involves the following steps (at least):

  • Converts the scheme and host to lower case.

  • Capitalizes letters in escape sequences.

  • Decodes percent-encoded octets of unreserved characters.

  • Removes the default port (port 80 for http).

Example:

my $normalizer = URL::Normalize->new(
    url => 'HTTP://www.example.com:80/%7Eusername/',
);

$normalizer->make_canonical;

print $normalizer->url; # http://www.example.com/~username/

remove_dot_segments

The ., .. and ... segments will be removed and "folded" (or "flattened", if you prefer) from the URL.

This method does NOT follow the algorithm described in RFC 3986: Uniform Resource Indentifier, but rather flattens each path segment.

Also keep in mind that this method doesn't (because it can't) account for symbolic links on the server side.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/../a/b/../c/./d.html',
);

$normalizer->remove_dot_segments;

print $normalizer->url; # http://www.example.com/a/c/d.html

remove_directory_index

Removes well-known directory indexes, eg. index.html, default.asp etc.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/index.cgi?foo=/',
);

$normalizer->remove_directory_index;

print $normalizer->url; # http://www.example.com/?foo=/

The default regular expressions for matching a directory index are:

  • /default\.aspx?

  • /default\.s?html?

  • /home\.s?html?

  • /index\.cgi

  • /index\.php\d?

  • /index\.pl

  • /index\.s?html?

You can override these by sending in your own list of regular expressions when creating the URL::Normalizer object:

my $normalizer = URL::Normalize->new(
    url               => 'http://www.example.com/index.cgi?foo=/',
    dir_index_regexps => [ 'MyDirIndex\.html' ], # etc.
);

You can also choose to add regular expressions after the URL::Normalize object has been created:

my $normalizer = URL::Normalize->new(
    url               => 'http://www.example.com/index.cgi?foo=/',
    dir_index_regexps => [ 'MyDirIndex\.html' ], # etc.
);

# ...

$normalizer->add_directory_index_regexp( 'MyDirIndex\.html' );

Keep in mind that the regular expression are case-insensitive, so the default /default\.aspx? expression will also match /Default\.aspx?.

sort_query_parameters

Sorts the URL's query parameters alphabetically.

Uppercased parameters will be lowercased DURING sorting, but the parameters will be in the original case AFTER sorting. If there are multiple values for one parameter, the key/value-pairs will be sorted as well.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/?b=2&c=3&a=0&A=1',
);

$normalizer->sort_query_parameters;

print $normalizer->url; # http://www.example.com/?a=0&A=1&b=2&c=3

remove_duplicate_query_parameters

Removes duplicate query parameters, i.e. where the key/value combination is identical with another key/value combination.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/?a=1&a=2&b=4&a=1&c=4',
);

$normalizer->remove_duplicate_query_parameters;

print $normalizer->url; # http://www.example.com/?a=1&a=2&b=3&c=4

remove_empty_query_parameters

Removes empty query parameters, i.e. where there are keys with no value. This only removes BLANK values, not values considered to be no value, like zero (0).

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/?a=1&b=&c=3',
);

$normalizer->remove_empty_query_parameters;

print $normalizer->url; # http://www.example.com/?a=1&c=3

remove_empty_query

Removes empty query from the URL.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/foo?',
);

$normalizer->remove_empty_query;

print $Normalize->url; # http://www.example.com/foo

remove_fragment

Removes the fragment from the URL, but only if seems like they are at the end of the URL.

For example http://www.example.com/#foo will be translated to http://www.example.com/, but http://www.example.com/#foo/bar will stay the same.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/bar.html#section1',
);

$normalizer->remove_fragment;

print $normalizer->url; # http://www.example.com/bar.html

remove_fragments

Like remove_fragment, but removes EVERYTHING after a #.

remove_duplicate_slashes

Remove duplicate slashes from the URL.

Example:

my $normalizer = URL::Normalize->new(
    url => 'http://www.example.com/foo//bar.html',
);

$normalizer->remove_duplicate_slashes;

print $normalizer->url; # http://www.example.com/foo/bar.html

remove_query_parameter

Convenience method for removing a specific parameter from the URL. If the parameter is mentioned multiple times (?a=1&a=2), all occurences will be removed.

remove_query_parameters

Convenience method for removing multiple parameters from the URL. If the parameters are mentioned multiple times (?a=1&a=2), all occurences will be removed.

SEE ALSO

AUTHOR

Tore Aursand, <toreau at gmail.com>

BUGS

Please report any bugs or feature requests to the web interface at https://github.com/toreau/URL-Normalize/issues

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc URL::Normalize

You can also look for information at:

LICENSE AND COPYRIGHT

The MIT License (MIT)

Copyright (c) 2012-2021 Tore Aursand

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.