# Discovery.xml lookup: extension or MIME type?

**URL:** <https://forum.collaboraonline.com/t/discovery-xml-lookup-extension-or-mime-type/3622>\
**Category:** Uncategorized\
**Created:** [April 22, 2025, 11:33am UTC](https://forum.collaboraonline.com/t/discovery-xml-lookup-extension-or-mime-type/3622 "2025-04-22T11:33:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![donquixote](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@donquixote](https://forum.collaboraonline.com/u/donquixote)\
**Post date:** [April 22, 2025, 11:33am UTC](https://forum.collaboraonline.com/t/discovery-xml-lookup-extension-or-mime-type/3622/1 "2025-04-22T11:33:24Z")

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The discovery.xml has one section with file extensions, and another (“legacy”) section with MIME types.

I think for a lookup what to do with a given file, the extension part should always be checked first, is that correct?

This is also what we see in Microsoft WOPI documentation, [WOPI discovery | Microsoft Learn](https://learn.microsoft.com/en-us/microsoft-365/cloud-storage-partner-program/online/discovery#wopi-discovery-actions)

I am asking just to be sure, and because I think it needs to be explained in more detail in the documentation.

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**Author:** ![darshan](https://dub1.discourse-cdn.com/flex013/user_avatar/forum.collaboraonline.com/darshan/32/2230_2.png) [@darshan](https://forum.collaboraonline.com/u/darshan)\
**Post date:** [May 20, 2025, 7:18am UTC](https://forum.collaboraonline.com/t/discovery-xml-lookup-extension-or-mime-type/3622/2 "2025-05-20T07:18:09Z")

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Closed on May 20, 2025, 7:18am UTC