Parsing HTML and replacing strings [duplicate] - php

Question

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How do you parse and process HTML/XML in PHP?
(31 answers)
Closed 3 years ago.
I have a large quantity of partial HTML stored in a CMS database.
I'm looking for a way to go through the HTML and find any <a></a> tags that don't have a title and add a title to them based on the contents of the tags.
So if I had some text I'd like to modify the tag to look like:
<a title="some text" href="somepage"></a>
Some tags already have a title and some anchor tags have nothing between them.
So far I've managed to make some progress with php and regex.
But I can't seem to be able to get the contents of the anchors, it just displays either a 1 or a 0.
<?php
$file = "test.txt";
$handle = fopen("$file", "r");
$theData = fread($handle, filesize($file));
$line = explode("\r\n", $theData);
$regex = '/^.*<a ((?!title).)*$/'; //finds all lines that don't contain an anchor with a title
$regex2 = '/<a .*><\/a>/'; //finds all lines that have nothing between the anchors
$regex3 = '/<a.*?>(.+?)<\/a>/'; //finds the contents of the anchors
foreach ($line as $lines)
{
if (!preg_match($regex2, $lines) && preg_match($regex, $lines)){
$tags = $lines;
$contents = preg_match($regex3, $tags);
$replaced = str_replace("<a ", "<a title=\"$contents\" ", $lines);
echo $replaced ."\r\n";
}
else {
echo $lines. "\r\n";
}
}
?>
I understand regex is probably not the best way to parse HTML so any help or alternate suggestions would be greatly appreciated.

Answer 1

Use PHP's built-in DOM parsing. Much more reliable than regex. Be aware that loading HTML into the PHP DOM will normalize it.
$doc = new DOMDocument();
#$doc->loadHTML($html); //supress parsing errors with #
$links = $doc->getElementsByTagName('a');
foreach ($links as $link) {
if ($link->getAttribute('title') == '') {
$link->setAttribute('title', $link->nodeValue);
}
}
$html = $doc->saveHTML();

Answer 2

If it was coherent, you could use a simplistic regex. But it'll fail if your anchors have classes or anything. Also it doesn't corrently encode the title= attribute:
preg_replace('#<(a\s+href="[^"]+")>([^<>]+)</a>#ims', '<$1 title="$2">$2</a>',);
Therefore phpQuery/querypath is likely the robuster approach:
$html = phpQuery::newDocument($html);
foreach ($html->find("a") as $a) {
if (empty($a->attr("title")) {
$a->attr("title", $a->text());
}
}
print $html->getDocument();

Answer 3

Never use regex on parsing HTML. In php, use DOM.
Here's a more simple one: http://simplehtmldom.sourceforge.net/