How to get text between two strings with special characters in ruby? - ruby

Question

I have a string (#description) that contains HTML code and I want to extract the content between two elements. It looks something like this
<b>Content title<b><br/>
*All the content I want to extract*
<a href="javascript:print()">
I've managed to do something like this
#want = #description.match(/Content title(.*?)javascript:print()/m)[1].strip
But obviously this solution is far from perfect as I get some unwanted characters in my #want string.
Thanks for your help
Edit:
As requested in the comments, here is the full code:
I'm already parsing an HTML document doing something where the following code:
#description = #doc.at_css(".entry-content").to_s
puts #description
returns:
<div class="post-body entry-content">
<img alt="Photo title" height="333" src="http://photourl.com" width="500"><br><br><div style="text-align: justify;">
Some text</div>
<b>More text</b><br><b>More text</b><br><br><ul>
<li>Numered item</li>
<li>Numered item</li>
<li>Numered item</li>
</ul>
<br><b>Content Title</b><br>
Some text<br><br>
Some text(with links and images)<br>
Some text(with links and images)<br>
Some text(with links and images)<br>
<br><br><img src="http://url.com/photo.jpg">
<div style="clear: both;"></div>
</div>
The text can include more paragraphs, links, images, etc. but it always starts with the "Content Title" part and ends with the javascript reference.

Answer 1

This XPath expression selects all (sibling) nodes between the nodes $vStart and $vEnd:
$vStart/following-sibling::node()
[count(.|$vEnd/preceding-sibling::node())
=
count($vEnd/preceding-sibling::node())
]
To obtain the full XPath expression to use in your specific case, simply substitute $vStart with:
/*/b[. = 'Content Title']
and substitute $vEnd with:
/*/a[#href = 'javascript:print()']
The final XPath expressions after the substitutions is:
/*/b[. = 'Content Title']/following-sibling::node()
[count(.|/*/a[#href = 'javascript:print()']/preceding-sibling::node())
=
count(/*/a[#href = 'javascript:print()']/preceding-sibling::node())
]
Explanation:
This is a simple corollary of the Kayessian formula for the intersection of two nodesets $ns1 and $ns2:
$ns1[count(.|$ns2) = count($ns2)]
In our case, the set of all nodes between the nodes $vStart and $vEnd is the intersection of two node-sets: all following siblings of $vStart and all preceding siblings of $vEnd.
XSLT - based verification:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:variable name="vStart" select="/*/b[. = 'Content Title']"/>
<xsl:variable name="vEnd" select="/*/a[#href = 'javascript:print()']"/>
<xsl:template match="/">
<xsl:copy-of select=
"$vStart/following-sibling::node()
[count(.|$vEnd/preceding-sibling::node())
=
count($vEnd/preceding-sibling::node())
]
"/>
==============
<xsl:copy-of select=
"/*/b[. = 'Content Title']/following-sibling::node()
[count(.|/*/a[#href = 'javascript:print()']/preceding-sibling::node())
=
count(/*/a[#href = 'javascript:print()']/preceding-sibling::node())
]
"/>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML document (converted to a well-formed XML document):
<div class="post-body entry-content">
<a href="http://www.photourl">
<img alt="Photo title" height="333" src="http://photourl.com" width="500"/>
</a>
<br />
<br />
<div style="text-align: justify;">
Some text</div>
<b>More text</b>
<br />
<b>More text</b>
<br />
<br />
<ul>
<li>Numered item</li>
<li>Numered item</li>
<li>Numered item</li>
</ul>
<br />
<b>Content Title</b>
<br />
Some text
<br />
<br />
Some text(with links and images)
<br />
Some text(with links and images)
<br />
Some text(with links and images)
<br />
<br />
<br />
<a href="javascript:print()">
<img src="http://url.com/photo.jpg"/>
</a>
<div style="clear: both;"></div>
</div>
the two XPath expressions (with and without variable references) are evaluated and the nodes selected in each case, conveniently delimited, are copied to the output:
<br/>
Some text
<br/>
<br/>
Some text(with links and images)
<br/>
Some text(with links and images)
<br/>
Some text(with links and images)
<br/>
<br/>
<br/>
==============
<br/>
Some text
<br/>
<br/>
Some text(with links and images)
<br/>
Some text(with links and images)
<br/>
Some text(with links and images)
<br/>
<br/>
<br/>

Answer 2

To test your HTML, I have added tags around your code then pasting it in a file
xmllint --html --xpath '/html/body/div/text()' /tmp/l.html
output :
Some text
Some text
Some text
Some text
Now, you can use an Xpath module in ruby and re-use the Xpath expression
You will find many examples on stackoverflow website searches.