How can I check if a SharePoint file exists programmatically in an MDA?

[Spinner]

I have some client-side javascript in a model-driven app that should show/hide controls based on whether a particular file in the associated record's SharePoint document location exists.

My thought was to send an HEAD request with XMLHttpRequest; if I receive a 200 OK response, then I should be able to assume the file exists. If I open the path of the file in my browser, it opens successfully. However, when I call it from my script, the response is 403 Forbidden - presumably because the request does not carry appropriate authentication.

Am I missing some easier/better way of accomplishing my objective? I can't see any method in the Xrm Web Api that would allow me to do it.

[LinnZawWin]

You won't be able to do Xrm.WebApi call because SharePoint file information is not stored in Dataverse.

This article will teach you how to get a SharePoint OAuth Access Token.

https://www.engineeredcode.com/blog/getting-a-sharepoint-oauth-access-token-in-a-dynamics-365-web-re...

I am not sure if the above article (about the solution with HTML webresource) would solve your issue. If it is not, you can definitely build cloud flow in Power Automate with HTTP request trigger. You can call the flow from JavaScript as mentioned in the blog post below by passing through the current record GUID. In the flow, try to build the full SharePoint URL of the Document Location of the record based on the GUID input parameter. Then, check the existence of the a particular file and respond back to the JavaScript which will show/hide controls based on the outcome.

https://crmminds.com/2022/11/02/dynamics-365-call-power-automate-flow-from-javascript/

[Spinner · Accepted solution]

Thanks @LinnZawWin.

After some further thought and research I found another way to accomplish my aim. I didn't need the file content, but only needed to confirm that it existed. To do that I used Xrm.WebApi to query the Dataverse table sharepointdocument. This seems to be a special sort of table that does not display any rows, and it cannot be queried with the usual $filter parameter. However, it can be queried with the fetchXml parameter.

//make Xrm call
let fetchQueryData = `<fetch distinct="false" mapping="logical" returntotalrecordcount="true" page="1" count="1" no-lock="false">
<entity name="sharepointdocument">
<attribute name="documentid" />
<attribute name="sharepointdocumentid" />
<attribute name="fullname" />
<attribute name="relativelocation" />
<attribute name="filetype" />
<attribute name="absoluteurl" />
<attribute name="editurl" />
    <order attribute="relativelocation" descending="false" />
    <filter>
        <condition attribute="isrecursivefetch" operator="eq" value="1" />
    </filter>
    <filter type="and">
        <condition attribute="absoluteurl" operator="eq"
            value="` + path + `" />
    </filter>
    <link-entity name="prefix_***entityname***" from="prefix_***entityname***id" to="regardingobjectid" alias="bb">
        <filter type="and">
            <condition attribute="prefix_***entityname***id" operator="eq" uitype="prefix_***entityname***"
                value="`+ entityId.slice(1, -1) + `" />
        </filter>
    </link-entity>
</entity>
</fetch>`;

return Xrm.WebApi.retrieveMultipleRecords("sharepointdocument", "?fetchXml=" + encodeURIComponent(fetchQueryData)).then(/*handle result*/)

This allows filtering by absoluteurl. Curiously, the query stops working if I remove the <link-entity> node, although I have no need for it in the output.

I can then check whether the results are empty (i.e. the file was not found) or not, and use the result of that test to perform the actions I want.

[LinnZawWin]

It's good to know about it.

Thanks for sharing your answer with us, @Spinner.

Thanks for highlighting that the query stops working if you remove the <link-entity> node. That is the piece that I was missing and why my query did not work previously when I tested before responding to your thread..