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">
<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 text can include more paragraphs, links, images, etc. but it always starts with the "Content Title" part and ends with the javascript reference.
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/>
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.
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