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HTML::Parser Skip Style Content

by spickles (Scribe)
on Mar 09, 2010 at 20:33 UTC ( [id://827624]=perlquestion: print w/replies, xml ) Need Help??

spickles has asked for the wisdom of the Perl Monks concerning the following question:

Anyone know how to skip the entire content between two HTML tags? I'm using HTML::Parser, and I have figured out how to use the start and end subclasses to match on certain tags and manipulate them. If there is text within those tags I want to keep or modify, I print them to an output file. So I thought that if I matched on a style tag and simply returned (rather than printing the text to my output file) that it wouldn't be there. But now I understand that the text within the tags is processed by the separate subclass for text. What I'd like to do is match on the <style></style> tags and NOT print the text between them.

#!c:/perl/bin/perl

#This version allows the use of a filename specified on the command li
+ne
use strict;
use warnings;

package HTMLStrip;
use base "HTML::Parser";
#system("cls");
my $output = "c:/perl/bin/parseOutput.txt";
if (-e $output) {
    unlink $output;
}
open PARSETEXT,'>',$output or die $!;
my $p = new HTMLStrip;
# parse line-by-line, rather than the whole file at once
    while (<>) {
        $p->parse($_);
    }
# flush and parse remaining unparsed HTML
$p->eof;
close PARSETEXT;

sub text {
    my ($self, $text) = @_;
    chomp($text);
    $text =~ s/#.*//;            # comments
    $text =~ s/^\s+//;           # leading whitespace
    $text =~ s/\s+$//;           # trailing whitespace
    #Once the beginning comment if found, remove style
    if ($text =~ /^<\!--$/) {
        next unless ($text =~ /^-->$/);
    }
    #Print non-blank lines
    if (length($text) > 0) {
        print PARSETEXT $text . "\n";
    }
}

#Process OPENING/STARTING HTML tags
sub start {
    my ($self, $tag, $attr, $attrseq, $origtext) = @_;
    
    #We're only interested in dealing with table tags
    if ($tag =~ /^table$/) {
        print PARSETEXT "\n************* BEGIN TABLE ****************\
+n";
    }
    if ($tag =~ /^tr$/) {
        print PARSETEXT "\n";
    }
    if ($tag =~ /^td$/) {
        print PARSETEXT "\t";
        if (defined $attr->{'class'}) {
            if ($attr->{'class'} =~ /alarmClear/) {
                print PARSETEXT "OK";
            }
            if ($attr->{'class'} =~ /alarmSet/) {
                print PARSETEXT "ALARM";
            }
        }    
    }
}

#Process CLOSING/ENDING HTML tags
sub end {
    my($self, $tag, $origtext) = @_;
    if ($tag =~ /^table$/) {
        print PARSETEXT "\n************* END TABLE ****************\n"
+;
    }
}

[download]

############################################################
############################################################
HTML FILE CONTENTS

<!DOCTYPE html PUBLIC
    "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>System Status</title>

        <style type="text/css">
        <!--
    
/* colors to use:
"CSI Blue" 004683
"CSI Red"  7e2d41
"CSI Grey" e5e5e5
"Liz Green" 00CC33
*/

body {
    background-color: #FFFFFF;
    color: #004683;
}

dt {
    font-weight: bold;
}

#main {
    float: left;
    margin: 1em;
}

#menu {
    float: left;
    margin: 1em;
    font-family: sans-serif; 
    background-color: #7e2d41;
}

#menu ul {
    list-style: none;
    margin: 0;
    padding: 0;
}
        
#menu li {
    margin: 1em;
}

#menu li a {
    color: #fff;
    text-decoration: none;
}

#menu li a {
    width: auto;
}

div.messages {
        /*width: 70%;*/
        padding: 1em;
        margin-top: 1em;
        margin-bottom: 1em;
        font-size: x-large;
        border: thin solid black;
}

#messages {
        /*width: 70%;*/
        padding: 1em;
        margin-top: 1em;
        margin-bottom: 1em;
        font-size: x-large;
        border: thin solid black;
}

/* TODO trash all these? */
.tallrow {
        padding-bottom: 6em;
        /*width: 70%;*/
}

.input {
        /*width: 45%;*/
        float: right;
}

.info {
        float: right;
}
/* TODO end of area to trash? */

table.bigdata {
    text-align: center;
}

div.boxer {
    padding: 1em;
    background-color: #e5e5e5;
    border: thin solid black;
}

td.label {
    text-align: right;
    padding-right: 1em;
}

td.labelInvalid {
    text-align: right;
    padding-right: 1em;
    color: red;
}

td.lineitem {
    text-align: left;
}

th {
    padding-right: 1em;
}

tr.spacer {
    height: 1em;
}

.section {
    text-align: right;
}

td.alarmSet {
        background-color: red;
        color:white;
}

td.alarmSet:after { content: "ALARM"; }


td.alarmClear { background-color: #00CC33; }

td.alarmClear:after { content: "OK"; }


        -->
        </style>
    
</head>
<body onLoad="setTimeout('reload()',60000)" >
<div id="menu"><ul><li><a href="index.cgi">System Status</a></li><li><
+a href="netconf.cgi">Local Network</a></li><li><a href="rf.cgi">RF Co
+nfiguration</a></li><li><a href="programfilter.cgi">Program a Filter<
+/a></li><li><a href="remotenetconf.cgi">Remote Network</a></li><li><a
+ href="snmpconf.cgi">SNMP Configuration</a></li><li><a href="status.c
+gi">System Health</a></li><li><a href="install.cgi">Install Software<
+/a></li><li><a href="reboot.cgi">Reboot</a></li></ul></div><div id="m
+ain" onLoad=setTimeout('reload()',60000)><h1>System Status</h1>
    <script type="text/javascript">
    function reload()
    {
        window.location.reload();
    }
    </script>

    <table class="bigdata">
        <tr>
            <td class="label"><b>Timestamp</b></td>
            <td colspan="4" class="lineitem"> 2010:03:09 - 18:26:45 </
+td>
        </tr>

        <tr>
            <td class="label"><b>System Uptime</b></td>
            <!-- I'd like to use colspan="0" but IE sucks. -->
            <td colspan="4" class="lineitem">
                16 days 3 hours 5 minutes
            </td>
        </tr>

        <tr>
            <td class="label"><b>Software Version</b></td>
            <td colspan="4" class="lineitem"> 2.2.4 REL </td>
        </tr>

        <tr>
            <td class="label"><b>Serial Number</b></td>
            <td colspan="4" class="lineitem"> CFB90357-000000 </td>
        </tr>
 
        <tr>
            <td class="label"><b>Model Number</b></td>
            <td colspan="4" class="lineitem"> DSP85-C/P </td>
        </tr>

        <tr>
            <td class="label"><b>Item Number</b></td>
            <td colspan="4" class="lineitem"> CS10-377-403 </td>
        </tr>

        <tr>
            <td class="label"><b>Location</b></td>
            <td colspan="4" class="lineitem"> Unknown </td>
        </tr>

        <tr class="spacer" />
 
            <tr>
                <th></th>
                <th colspan="2"> Band 1 (CELL) </th>
                <th colspan="2"> Band 2 (PCS) </th>
            </tr>
         <tr> <th align="right">Active Filter</th> <td colspan="2"><tt
+>cgA0-0</tt></td><td colspan="2"><tt>pgA0B4B5F0C5-0</tt></td> 
        </tr> 
        <tr class="spacer" /> 
        <tr>
            <th style="text-align:right">Power</th>
     <th> Down Link </th> <th> Up Link</th>  <th> Down Link </th> <th>
+ Up Link</th> 
        </tr>

        <tr>
            <td class="label">
                In-band Input<sup><a target="_blank" href="help.html#1
+">?</a></sup> (dBm)
            </td>
    <td>-35.6</td><td>&le; -66.0</td><td>-43.4</td><td>&le; -66.0</td>
        </tr>
        <tr>
            <td class="label">
                Measured Output<sup><a target="_blank" href="help.html
+#2">?</a></sup> (dBm)
            </td>
    <td>18.6</td><td>&le; 4.0</td><td>22.8</td><td>&le; 4.0</td>
            </tr>
            <tr>
                <td class="label">
                    Composite Input<sup><a target="_blank" href="help.
+html#4">?</a></sup> (dBm)
                </td>
        <td>-33.9</td><td>-43.4</td><td>-23.7</td><td>&le; -53.0</td>
        </tr>

        <tr class="spacer" />

        <tr class="section">
            <th>Gain Control</th>
        </tr>

        <tr>
            <td class="label">AGC Mode</td>
    <td colspan="2">On</td><td colspan="2">On</td>
        </tr>

        <tr>
            <td class="label">AGC Attenuation (dB)</td>
    <td>0.0</td><td>0.0</td><td>0.0</td><td>0.0</td>
        </tr>

        <tr>
            <td class="label">System Gain</td>
    <td>53.5</td><td>70.0</td><td>66.0</td><td>70.0</td> 
        </tr>

        <tr class="spacer" />
    
    <tr class="section">
    <th>RF Alarms</th>
    </tr>

    <tr>
    <td class="label">Over Range</td>
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Oscillation</td>
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    </tr>

    <tr>
    <td class="label">VSWR</td>
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Out of Band Overdrive</td>
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Low Signal</td>
    <td class="alarmClear" />
    <td />
    <td class="alarmClear" />
    <td />
    </tr>

    <tr>
    <td class="label">No Signal</td>
    <td class="alarmClear" />
    <td />
    <td class="alarmClear" />
    <td />
    </tr>

    <tr class="spacer" />

    <tr class="section">
    <th>System Alarms</th>
    </tr>

    <tr>
    <td class="label">Synthesizer Lock</td>
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    <td class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Voltage</td>
    <td colspan="2" class="alarmClear" />
    <td colspan="2" class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Temperature</td>
    <td colspan="2" class="alarmClear" />
    <td colspan="2" class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Software</td>
    <td colspan="2" class="alarmClear" />
    <td colspan="2" class="alarmClear" />
    </tr>

    <tr>
    <td class="label">Hardware</td>
    <td colspan="2" class="alarmClear" />
    <td colspan="2" class="alarmClear" />
    </tr>
 
    </table>

</div></body>
</html>

[download]

Regards,

Scott

Replies are listed 'Best First'.
Re: HTML::Parser Skip Style Content
by runrig (Abbot) on Mar 09, 2010 at 20:38 UTC
    Set a flag when you hit a style start tag, and unset it when you hit the end tag. Then in the text handler (and any other handler where you might print), just return if the flag is set.

    Update: This would not work if there are nested style tags. In that case, use an array as a stack for your "flag", and push a value on it on every style start tag, pop when you hit the end tag. As long as the array contains anything, you're inside style tags.

[reply]
      In that case, use an array as a stack for your "flag"...

      Wouldn't incrementing/decrementing a simple scalar serve the same purpose (indicating the level of nestedness — similarly to counting opening/closing parentheses)?

[reply]
        Um, yeah, that'd work too. And is simpler. 8-)
[reply]

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