# FM ODATA API - Support for headers: ETag and If-Match?

**URL:** <https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474>\
**Category:** Questions\
**Tags:** odata\
**Created:** [November 19, 2020, 2:37am UTC](https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474 "2020-11-19T02:37:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![steve\_ssh](https://yyz2.discourse-cdn.com/flex030/user_avatar/the.fmsoup.org/steve_ssh/32/160_2.png) [@steve\_ssh](https://the.fmsoup.org/u/steve_ssh)\
**Post date:** [November 19, 2020, 2:37am UTC](https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474/1 "2020-11-19T02:37:33Z")

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Hello friends,

I am endeavoring to gain some familiarity with what options open up with the availability of ODATA.

In particular, I am studying possibilities for performing transactional edits using ODATA.

The batch and change-set features already show a lot of promise.

**There is one other feature in the ODATA spec which catches my eye as being potentially very useful/powerful:**

- The [If-Match](http://docs.oasis-open.org/odata/odata/v4.0/errata03/os/complete/part1-protocol/odata-v4.0-errata03-os-part1-protocol-complete.html#_Toc453752230) header.

My understanding is that this header can be leveraged to conditionally execute a request, where the determining condition for execution is whether the target record has been modified since it was returned by a previous query.

Is anyone here aware of whether or not the ODATA API for FM has support for the [If-Match](http://docs.oasis-open.org/odata/odata/v4.0/errata03/os/complete/part1-protocol/odata-v4.0-errata03-os-part1-protocol-complete.html#_Toc453752230) header ?

I plan to test this out on my own, soon, but I just lost access to the dev Linux server that I was using to play around with ODATA, and so I may have to wait a while...

Thanks, and kind regards to all.

-Steve

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**Author:** ![WimDecorte](https://avatars.discourse-cdn.com/v4/letter/w/b19c9b/32.png) [@WimDecorte](https://the.fmsoup.org/u/WimDecorte)\
**Post date:** [November 19, 2020, 11:45am UTC](https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474/2 "2020-11-19T11:45:15Z")

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Did you have any mention of it in the OData guide?

> **[Claris FileMaker 19 OData Guide](https://help.claris.com/en/odata-guide/)**

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<div class="post-metadata">

**Author:** ![WimDecorte](https://avatars.discourse-cdn.com/v4/letter/w/b19c9b/32.png) [@WimDecorte](https://the.fmsoup.org/u/WimDecorte)\
**Post date:** [November 19, 2020, 11:45am UTC](https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474/3 "2020-11-19T11:45:54Z")

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> [@steve\_ssh](#):
>
> I just lost access to the dev Linux server that I was using to play around with ODATA, and so I may have to wait a while...

If you have access a FM Cloud instance; those have had OData for a few versions already.

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<div class="post-metadata">

**Author:** ![steve\_ssh](https://yyz2.discourse-cdn.com/flex030/user_avatar/the.fmsoup.org/steve_ssh/32/160_2.png) [@steve\_ssh](https://the.fmsoup.org/u/steve_ssh)\
**Post date:** [November 19, 2020, 2:01pm UTC](https://the.fmsoup.org/t/fm-odata-api-support-for-headers-etag-and-if-match/1474/4 "2020-11-19T14:01:53Z")

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No mention of it in the guide, thank you @WimDecorte.

On the topic of the guide, however, I will mention that, by and large, it has made it extremely easy to dive in with Postman and get familiar with FMP and ODATA.