Getting null response from graph Api for messages but receives a Nextlink

Question

/users/mailboxId/mailFolders/folderId/messages/delta?$select=id,createdDateTime,lastModifiedDateTime,changeKey,categories

I usually fetch 250 messages per request and continue calling the @odata.nextLink until I receive the @odata.deltaLink. However, in one particular case, I received a null response body that contained only the @odata.nextLink (no message items). When I followed that next link, I was able to retrieve additional messages.

I’m trying to understand why this happens and how to properly handle such a scenario.

#microsoftgraph #graphapi #exchangeonline

Answer 1

Hi Dinesh,

Thank you for posting your question in the Microsoft Q&A forum. 

I reviewed the behavior you described and found relevant guidance in the official Microsoft documentation here: https://learn.microsoft.com/en-us/graph/delta-query-overview#use-delta-query-to-track-changes-in-a-resource-collection.

The documentation states:

Based on this, the correct approach is to continue calling the @odata.nextLink until you receive the @odata.deltaLink, as you have already been doing. This is expected behavior and not an error.

While the documentation does not explicitly explain why an empty page occurs, here is a plausible hypothesis based on how delta queries work:

• Delta query, also called change tracking, enables applications to discover newly created, updated, or deleted entities without performing a full read of the target resource with every request. Microsoft Graph applications can use delta query to efficiently synchronize changes with a local data store. During paging, some items may have been deleted or moved after the initial snapshot, leaving a page with no items but still requiring continuation to complete the session. The @odata.nextLink ensures you retrieve all remaining changes before the final @odata.deltaLink is issued.

I hope the information above helpful.

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