in reply to Using example script correctly for opening cpan module

Edit: Did some testing, and indeed quoting the regexp seems to make Mech happy. This seems to work: 

my $link = $browser->find_link( text_regex => qr{$module_name} );
$browser->follow_link( url => $link->url );

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or, more concisely: 
$browser->follow_link( url => $browser->find_link(text_regex => qr{$mo
+dule_name})->url );

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Cheers!

earlier ... Hmm, the string 'WWW::Mechanize' works as a pattern in a hand-rolled regexp . . .

The docs for WWW::Mechanize only mention text_regex as an attribute of find_link, not follow_link, and also that a regexp passed to follow_link is matched against the URL, not the display text.

Also, maybe it will help to quote your regexp? Try: 

$browser->follow_link( url => $browser->find_link( text_regex => $modu
+le_name )->url );

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or maybe 
$browser->follow_link( text_regex => qr{$module_name} );

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Hope this helps!

The way forward always starts with a minimal test.

Replies are listed 'Best First'.
Re^2: Using example script correctly for opening cpan module
by Aldebaran (Curate) on Sep 09, 2015 at 07:22 UTC

    Thank you 1nickt, I'm relieved that this did indeed need a tweak. Your suggestion works perfectly for the case that ARGV[0] actually matches some link. I made a more verbose example to show what happens when one letter is off. What seems counter-intuitive about this was what constituted success, and the output gave me half an idea why the original script was sending me down the rabbit hole of the .css link. It is the first link, and I can well imagine that default behavior goes that way when the regex fails. This is a bit verbose, so I'll use readmore tags:

    Read more... (3 kB)

    It seems to me that the last place you want to be is stuck on the command line when you can't remember every proper keystroke in a module. I submit that testing whether $link is defined is worthwhile, and that one should get a window in either case. What's more, I found out that the case for failure in defining $link nevertheless turned up ranked, good alternatives. Furthermore, the 'mode' should be set to 'module' so that the behavior reflects the advertising. Now, I get no warnings or errors on the terminal, and ends up with a browser window that matched the regex or a ranked list of links that got close:

    C:\cygwin64\home\Fred\pages2\hunt>perl cpan10.pl HTML::Display

C:\cygwin64\home\Fred\pages2\hunt>perl cpan10.pl HTML::Displayz

C:\cygwin64\home\Fred\pages2\hunt>type cpan10.pl
#! /usr/bin/perl
use warnings;
use strict;

# work out the name of the module we're looking for
my $module_name = $ARGV[0]
  or die "Must specify module name on command line";

# create a new browser
use WWW::Mechanize;
my $browser = WWW::Mechanize->new();

# tell it to get the main page
$browser->get("http://search.cpan.org/");

# okay, fill in the box with the name of the
# module we want to look up
$browser->form_number(1);
$browser->field( "query", $module_name );
$browser->click();

my $link = $browser->find_link( text_regex => qr{$module_name} );

# make sure $link is defined
if ( defined $link ) {
  my $success2 = $browser->follow_link( url => $link->url );
  my $url = $browser->uri;
  system( 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe
+', $url );

}
else {
  $browser->back;
  $browser->submit_form(
    form_number => 1,
    fields      => { query => $module_name,
                     mode => 'module',
        },
  );
  my $url = $browser->uri;
  system( 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe
+', $url );

}

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    Anyways, that's what I can figure out tonight. Web automation is truly fantastic.

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