From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2013-03-27T08:05:17+09:00
Subject: Re: Nokogiri help parsing HTML

On Tue, Mar 26, 2013 at 11:40 PM, Paul Mena <lists@ruby-forum.com> wrote:
> I'm relatively new to Ruby (and therefore Nokogiri) and am trying to
> parse some HTML that will ultimately be written to a MySQL database.  In
> the interim, I'm writing it to a text file for troubleshooting purposes.
>
> Here's the relevant piece of the HTML I'd like to parse:
>
> <!-- body="start" -->
> <div class="mail">
> <address class="headers">
> <span id="from">
> <dfn>From</dfn>: Paul David Mena &lt;<a
> href="mailto:pauldavidmena_at_gmail.com?Subject=Re:%20twilight">pauldavidmena_at_gmail.com</a>&gt;
> </span><br />
> <span id="date"><dfn>Date</dfn>: Tue, 26 Mar 2013 18:13:21
> -0400</span><br />
> </address>
> <p>
> Line 1
> <br />
> Line 2
> <br />
> Line 3
> <br />
> <p><pre>
> --
> Paul David Mena
> --------------------
> pauldavidmena_at_gmail&#46;<!--nospam-->com
> </pre>
> <span id="received"><dfn>Received on</dfn> Tue Mar 26 2013 - 22:13:23
> EDT</span>
> </div>
> <!-- body="end" -->
>
> My goal is to strip out everything between the "address" and "pre" tags
> and to output only:

OK, so you want every tag that is a sibling of address and pre and is
within those two. I have found this StackOverFlow answer:

http://stackoverflow.com/a/6555376

which applied to your problem:

1.9.2p290 :001 > require 'nokogiri'
 => true
1.9.2p290 :002 > s = <<END
1.9.2p290 :003"> <!-- body="start" -->
1.9.2p290 :004"> <div class="mail">
[...snip...]
1.9.2p290 :031 > doc = Nokogiri::HTML(s)
1.9.2p290 :039 >
doc.xpath("//address/following-sibling::node()[count(.|
//pre/preceding-sibling::node())=count(//pre/preceding-sibling::node())]")
 => [#<Nokogiri::XML::Text:0xdb0114 "\n">,
#<Nokogiri::XML::Element:0xdaff84 name="p"
children=[#<Nokogiri::XML::Text:0xdafc28 "\nLine 1\n">,
#<Nokogiri::XML::Element:0xdafa5c name="br">,
#<Nokogiri::XML::Text:0xdaf728 "\nLine 2\n">,
#<Nokogiri::XML::Element:0xdaf5ac name="br">,
#<Nokogiri::XML::Text:0xdaf228 "\nLine 3\n">,
#<Nokogiri::XML::Element:0xdaf0ac name="br">]>,
#<Nokogiri::XML::Element:0xdaea80 name="p">]

will return a node set that contains the required nodes.

Hope this helps,

Jesus.