LWP::Simple for Perl 6, now with (partial) BasicAuth support and getstore()

I just pushed out another update for the LWP::Simple module for Perl 6. This time, the main work was:

  • refactoring the code and adding unit tests for the URL parsing (that might even grow into a Perl 6 URI module
  • adding partial basic auth support. To be complete and working, it needs to base64 encode the user/password pair. Not implemented yet. I'll see if I get around to it, or if someone has done it already.
  • adding a getstore() method, that writes on to disk the downloaded content. Unfortunately that needs to strip the HTTP headers and undestand chunked transfers for it to be remotely useful.

It was nice to see the module grow in both functionality, code and unit tests coverage. I had to workaround a couple of problems I couldn't understand. I was extremely lazy and I didn't even look up Synopses, so I assume it's my fault. However.

The first is the use of .match() and ~~ to match against a regular expression. I found that the following code:

my $hostname = 'cosimo:eelst@faveclub.eelst.com';
if $hostname.match('^cosimo') {
    # Doesn't enter here

doesn't trigger a match. However, this other here:

my $hostname = 'cosimo:eelst@faveclub.eelst.com';
if $hostname ~~ /^cosimo/ {
    # Does match

And, in the same way, something similarly surprising. The following code correctly matches:

my $hostname = 'cosimo:eelst@faveclub.eelst.com';
if $hostname ~~ /^ .+ : .+ @ .+ $/ {
    say '(user:pass@host) matches';
} else {
    say '(user:pass@host) does not match';

but adding captures makes the same exact regex fail:

my $hostname = 'cosimo:eelst@faveclub.eelst.com';
if $hostname ~~ /^ (.+) : (.+)  @ (.+) $/ {
    say '(with captures) matches';
} else {
    say '(with captures) does not match';

There are also very nice things about programming in Perl 6 that are slowly sucking me in this fantastic language. This is part of a test script for LWP::Simple:

# Test the parse_url() method
use v6;
use Test;
use LWP:: Simple;

my @test = (
    { User-Agent => 'Opera/9.80 (WinNT; 6.0) Version/10.60' },
    "User-Agent: Opera/9.80 (WinNT; 6.0) Version/10.60rn",

    { Connection => 'close' },
    "Connection: closern",

for @test -> %headers, $expected_str {
    my $hdr_str = LWP:: Simple.stringify_headers(%headers);
    is($hdr_str, $expected_str, 'OK - ' ~ $hdr_str);

Note how in the for statement we can "extract" the hash and string from the @test array with:

for @test -> %headers, $expected_string {
    # Loop body

It's not a big deal, other languages have it, but Perl 6 is filled with this small niceties that make the resulting code still feel like Perl, but also, don't know exactly, more robust perhaps?

So, to conclude:

  • Anyone with a Perl 6 implementation of MIME::Base64 ? Speak up before I create a monster :)
  • Anyone cares enough to take on the chunked transfer encoding support?

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