Home/ Questions/Q 8134441
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-06T10:01:56+00:00

I’m trying to figure out a regular expression on Ruby 1.8.7 for removing the

  • 0

I’m trying to figure out a regular expression on Ruby 1.8.7 for removing the thread from emails. For doing so I need to remove all content between mail boundaries that matches the thread pattern, for example, on Mac Mail I would need to remove the text in bold (sample HTML is simplified to avoid using a lot of space, real mails’ HTML is far less succinct):

From: XXXX
... mail headers ...
Content-Type: multipart/alternative;
  boundary="Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036"
... more mail headers ...

--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
  charset=us-ascii

New comment added from Mac Mail

On 12/06/2012, at 12:51, XXXX@example.com wrote:

> Thread
> text
> to be
> removed
>=20

--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html;
  charset=us-ascii

<html>... lots of HTML...

<span>On 12/06/2012, at 12:51, XXXX@example.com wrote:</span>

<span> Thread </span>
<span> text </span>
<span> to be </span>
<span> removed </span>
<span>=20 </span>
</html>=

--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036--

The regular expression I thought would capture the required text is:

--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036.+?(\bOn.+?)(?!--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036)

But this is not working as is capturing from the boundary right until the first “On “.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Ok, so the solution for this was pretty simple, I ended up with an expression like the following:

    --Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036.+?(On \\d{0,2}[\\/\\-]\\d{0,2}[\\/\\-]\\d{0,4}.+?)--Apple-Mail=_EFA7D6C2-C778-4C8E-AA13-C97DF1FA9036

    No need to perform a look-ahead/behind for this.

    • 0