Url Parsing in Perl

Here’s the translation of the Go URL parsing example to Perl, formatted in Markdown suitable for Hugo:

use strict;
use warnings;
use URI;
use Data::Dumper;

# We'll parse this example URL, which includes a
# scheme, authentication info, host, port, path,
# query params, and query fragment.
my $s = "postgres://user:pass@host.com:5432/path?k=v#f";

# Parse the URL and ensure there are no errors.
my $u = URI->new($s);

# Accessing the scheme is straightforward.
print $u->scheme . "\n";

# User contains all authentication info; we can get
# username and password individually.
print $u->userinfo . "\n";
print $u->user . "\n";
print $u->password . "\n";

# The host contains both the hostname and the port,
# if present. We can extract them separately.
print $u->host_port . "\n";
print $u->host . "\n";
print $u->port . "\n";

# Here we extract the path and the fragment after
# the #.
print $u->path . "\n";
print $u->fragment . "\n";

# To get query params in a string of k=v format,
# use query_string. You can also parse query params
# into a hash reference.
print $u->query_string . "\n";
my $m = { $u->query_form };
print Dumper($m) . "\n";
print $m->{k} . "\n";

This Perl script demonstrates URL parsing using the URI module, which provides functionality similar to Go’s net/url package. Here’s a breakdown of the code:

1. We use the URI module to parse and manipulate URLs.

2. We create a URI object from the example URL string.

3. We can access various components of the URL using methods provided by the URI object:

   • scheme for the URL scheme
   • userinfo for the full user information
   • user and password for individual authentication components
   • host_port for the full host and port
   • host and port for individual host components
   • path for the URL path
   • fragment for the fragment after the #

4. For query parameters, we use query_string to get the raw string and query_form to parse it into a hash reference.

5. We use Data::Dumper to print the parsed query parameters hash.

To run this Perl script, save it to a file (e.g., url_parsing.pl) and execute it with:

$ perl url_parsing.pl

The output will show the different pieces extracted from the URL, similar to the Go example.

Note that Perl’s URI module handles most of the parsing internally, so we don’t need to handle errors explicitly or use additional functions to split the host and port as in the Go example.