How do I find matching <pre> tags using a reqular expression?
Question
I am trying to create a simple blog that has code inclosed in <pre> tags.
I want to display "read more" after the first closing </pre> tag is encountered, thus showing only the first code segment.
I need to display all text, HTML, code up to the first closing </pre> tag.
What I've come up with so far is the follow:
/^(.*<\/pre>).*$/m
However, this matches every closing </pre> tag up to the last one encountered.
I thought something like the following would work:
/^(.*<\/pre>{1}).*$/m
It of course does not.
I've been using Rubular .
My solution thanks to your guys help:
require 'nokogiri'
module PostsHelper
def readMore(post)
doc = Nokogiri::HTML(post.message)
intro = doc.search("div[class='intro']")
result = Nokogiri::XML::DocumentFragment.parse(intro)
result << link_to("Read More", post_path(post))
result.to_html
end
end
Basically in my editor for the blog I wrap the blog preview in div class=intro Thus, only the intro is displayed with read more added on to it.
3 answers
solution1
6 ACCPTED 2011-12-29 05:55:48
This is not a job for regular expressions , but for a HTML/XML parser.
Using Nokogiri , this will return all <pre> blocks as HTML, making it easy for you to grab the one you want:
require 'nokogiri'
html = <<EOT
<html>
<head></head>
<body>
<pre><p>block 1</p></pre>
<pre><p>block 2</p></pre>
</body>
</html>
EOT
doc = Nokogiri::HTML(html)
pre_blocks = doc.search('pre')
puts pre_blocks.map(&:to_html)
Which will output:
<pre><p>block 1</p></pre>
<pre><p>block 2</p></pre>
solution2
1 2011-12-29 05:33:46
You can capture all text upto the first closing pre tag by modifying your regular expression to,
/^(.*?<\/pre>{1}).*$/m
This way you can get the matched text by,
text.match(regex)[1]
which will return only the text upto the first closing pre tag.
solution3
1 2011-12-29 05:35:50
Reluctant matching might help in your case:
/^(.*?<\/pre>).*$/m
But it's probably not the best way to do the thing, consider using some html parser, like Nokogiri .
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