Extract text from HTML - Perl using HTML::TreeBuilder

Question

I'm trying to access the .html files and extract the text in <p> tags. Logically, my code below should work. By using the HTML::TreeBuilder. I parse the html then extract text in <p> using find_by_attribute("p"). But my script came out with empty directories. Did i leave out anything?

#!/usr/bin/perl

use strict;
use HTML::TreeBuilder 3;
use FileHandle;

my @task = ('ar','cn','en','id','vn');

foreach my $lang (@task) {
mkdir "./extract_$lang", 0777 unless -d "./extract_$lang";
opendir (my $dir, "./$lang/") or die "$!";
my @files = grep (/\.html/,readdir ($dir));
closedir ($dir);

foreach my $file (@files) {
    open (my $fh, '<', "./$lang/$file") or die "$!";
    my $root = HTML::TreeBuilder->new;
    $root->parse_file("./$lang/$file");
    my @all_p = $root->find_by_attribute("p");
    foreach my $p (@all_p) {
        my $ptag = HTML::TreeBuilder->new_from_content ($p->as_HTML);
        my $filewrite = substr($file, 0, -5); 
        open (my $outwrite, '>>', "extract_$lang/$filewrite.txt") or die $!;
        print $outwrite $ptag->as_text . "\n";  
        my $pcontents = $ptag->as_text;
        print $pcontents . "\n";
        close (outwrite);
    }
close (FH);
}
}

My .html files are the plain text htmls from .asp websites e.g. http://www.singaporemedicine.com/vn/hcp/med_evac_mtas.asp

My .html files are saved in:

./ar/*
./cn/*
./en/*
./id/*
./vn/*

Answer 1

You are confusing element with attribute. The program can be written much more concisely:

#!/usr/bin/env perl
use strictures;
use File::Glob qw(bsd_glob);
use Path::Class qw(file);
use URI::file qw();
use Web::Query qw(wq);
use autodie qw(:all);

foreach my $lang (qw(ar cn en id vn)) {
    mkdir "./extract_$lang", 0777 unless -d "./extract_$lang";
    foreach my $file (bsd_glob "./$lang/*.html") {
        my $basename = file($file)->basename;
        $basename =~ s/[.]html$/.txt/;
        open my $out, '>>:encoding(UTF-8)', "./extract_$lang/$basename";
        $out->say($_) for wq(URI::file->new_abs($file))->find('p')->text;
        close $out;
    }
}

Answer 2

Use find_by_tag_name to search for tag names, not find_by_attribute.

Answer 3

You want find_by_tag_name, not find_by_attribute:

my @all_p = $root->find_by_tag_name("p");

From the docs:

$h->find_by_tag_name('tag', ...)

In list context, returns a list of elements at or under $h that have any of the specified tag names. In scalar context, returns the first (in pre-order traversal of the tree) such element found, or undef if none.

Answer 4

You might want to take a look at Mojo::DOM which lets you use CSS selectors.