Monday, 14 May 2018

SPFx: Calling Microsoft Graph API from an AAD secured Azure Function on behalf of a user

This post is part of a series where we explore consuming Azure AD secured Azure Functions from SharePoint Framework components. Articles in the series:

1) SharePoint Framework: Calling AAD secured Azure Function on behalf of a user
2) Calling Microsoft Graph API from an AAD secured Azure Function on behalf of a user (this post)
3) SharePoint Framework: Calling back to SharePoint from an AAD secured Azure Function on behalf of a user

The functionality shown in the post is preview only and not be used in production at this time.

In the previous post, we were successfully able to call an AAD secured Azure Function from a SharePoint Framework web part.

Now once we are in the Function, lets see how to make a call to the Microsoft Graph on behalf of the logged in user. We will only focus on the Azure Function here, to fully understand the set up and auth process, I recommend you check out the previous post.



Updates to the Azure AD app registration:


In order to call the Microsoft Graph, we will need to add a Client Secret to the Azure AD app registration.



We don't need to add any new permission scopes for the purposes of this post as we are going to make a call to the /v1.0/me endpoint which requires the User.Read permission. According to the SPFx docs, if we exchange the SPFx generated token for a MS Graph token, it will automatically have the User.Read.All permission scope.

If you want to do anything beyond this with the Microsoft Graph, you will need to add the relevant permissions scope and grant permissions to it. In the next post, we will see how to do this by granting permissions to the "Office 365 SharePoint Online" permissions scope.

Here is what we are going to do in this post:

When the Azure Function executes, we already have an access token sent by the SharePoint Framework AadHttpClient in the Authorization header. This access token has the "user_impersonation" scope which only allows it to access the Azure Function. It cannot be directly used to call the Microsoft Graph.

In order to obtain new access token that will work with the Microsoft Graph, we will have to request it using the existing access token. Once we have the new token, we are able to make a call to the Microsoft Graph:

Once this function is called from our SharePoint Framework web part, we are able to get data back from the graph:


Thanks for reading!

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