strip HTML Tags with perl

html perl parsing tags

17,060

Solution 1

An attempt to answer your misguided question

Problems

It's a bad habit to get into regex'ing out HTML because there are so many rules and ways to get around them, that may eventually open your code up to hacking techniques. While you might have a legitimate need for something simple now, it is very easy to reuse code and forget why it was a bad idea to reuse it, especially when you don't add comments like # This code is NOT secure and should not be used to parse HTML anywhere else!!! or # Christina Alguilera writes songs based on this code!!!

Example of differences in HTML that require lots of regex rules:

<div>...</div>
<div style="blah">
<div style="background:url(../div)">
<div style=".." class='noticesinglequote'>

The list goes on and that's only for well-formed HTML. Some other examples of problems include:

HTML elements closed improperly (eg <div><span></div></span>) or not at all
Spelling errors (eg <dvi>..</div>)
HTML designed with the intention to break your script
Other issues: comments, whitespaces, charsets, etc

Solution

You may have accepted an answer, but you should look at XML::Parser and HTML::TreeBuilder.

Rather than stripping out parts of the HTML Document, you are probably more interested in drilling down to the part of the document you want (eg everything in <body> or a certain div inside of it), which is why you most likely want something that one of the above modules provide. Not to mention, parsers can be used to do their best at removing all HTML elements and returning only text/CData.

Solution 2

As mentioned, don't use regular expressions for this. There are simply too many exceptions.

One CPAN module which can help is HTML::Strip:

use HTML::Strip;

my $hs         = HTML::Strip->new();
my $clean_text = $hs->parse( $raw_html );
$hs->eof;

It's worth learning what's available on the CPAN and making use of it. It will save you a lot of work in the long run.

Solution 3

Have a look at the HTML::Restrict module which allows you to strip away or restrict the HTML tags allowed. A minimal example that strips away all HTML tags:

use HTML::Restrict;

my $hr = HTML::Restrict->new();
my $processed = $hr->process('<b>i am bold</b>'); # returns 'i am bold'

I would recommend to stay away from HTML::Strip because it breaks utf8 encoding.

17,060

Author by

shinjuo

I have a bachelors in computer science and I am currently working as an applications developer. I mainly use java for server side code and connect client side with spring.

Updated on June 09, 2022

Comments

shinjuo almost 2 years

Whats the easiest way to strip the HTML tags in perl. I am using a regular expression to parse HTML from a URL which works great but how can I strip the HTML tags off?

Here is how I am pulling my HTML

 #!/usr/bin/perl -w
use strict;
use warnings;
use LWP::Simple;
my $now_string = localtime;

my $html = get("http://www.spc.noaa.gov/climo/reports/last3hours.html")
    or die "Could not fetch NWS page.";
$html =~ s/<script.*?<\'/script>/sg;
$html =~ s/<.+?>//sg;
$html =~ m{(Hail Reports.*)Wind Reports}s || die;
my @hail = $1;