Mime type matching: tika-mimetypes.xml

[Chris Bamford <cb...@mimecast.com>]

Hi, I was wondering exactly what this syntax means in tika-mimetypes.xml


<mime-type type="message/rfc822">
  <magic priority="50">
    <match value="Status:" type="string" offset="0"/>
    …
      <match value="Message-ID:" type="string" offset="0:8192"/>
    </match>
  </magic>
  ...

</mime-type>

Does offset="0:8192" mean match 'Message-ID:' anywhere in the first 8192 bytes?  If so, I'm not sure it is working properly as I have some eml files with this string near the beginning (but not at byte offset 0) where it does not match.  Is there some other logic involved which I am missing?

Thanks,

Chris


Chris Bamford
Lead Software Engineer

CityPoint, One Ropemaker Street, 
London,
EC2Y 9AW.

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Re: Mime type matching: tika-mimetypes.xml

[Nick Burch <ap...@gagravarr.org>]

On Wed, 9 Nov 2016, Chris Bamford wrote:
> <mime-type type="message/rfc822">
>  <magic priority="50">
>    <match value="Status:" type="string" offset="0"/>
>    \u2026
>      <match value="Message-ID:" type="string" offset="0:8192"/>
>    </match>
>  </magic>
>  ...
>
> </mime-type>
>
> Does offset="0:8192" mean match 'Message-ID:' anywhere in the first 8192 
> bytes?

Yup, that's it. If that is found, and nothing with a priority score of 
higher than 50 also matches, it'll return that type. If a higher priority 
matched, that other one will win.

(There's also some bits for if the extension matches a type in the same 
family, eg for specialising)

> If so, I'm not sure it is working properly as I have some eml files with 
> this string near the beginning (but not at byte offset 0) where it does 
> not match.  Is there some other logic involved which I am missing?

If you can share a small file that shows it, we can take a look for you.

Nick