SharePoint Rest API how to get Access Token?

Question

Just starting to work with SharePoint and Microsoft authentication and trying to get a SharePoint List into a JavaScript App. From Microsoft documentation, I need to use the following:

GET https://{site_url}/_api/web/lists/GetByTitle('List Title')
Authorization: "Bearer " + accessToken
Accept: "application/json;odata=verbose"

Have searched everywhere to find an definitive answer to how to obtain this accessToken. All the documentation I can find from Microsoft seem to be out of date. Does anyone know the current method to obtain an accessToken?

user_26843 · Answer

To call SharePoint specific APIs you need to get a SPO specific access token. You can "swap" an regular MS Graph refresh token for an SPO specific token by doing the following:

Get a delegated auth token from graph as you normally would (https://docs.microsoft.com/en-us/graph/auth-v2-user)
Use the refresh_token you got and exchange it for an SPO access token by calling the auth endpoint again:

POST https://login.microsoftonline.com/{{tenantName}}/oauth2/v2.0/token

With the following form data:

client_id=
client_secret=
refresh_token=
grant_type=refresh_token
scope=https://.sharepoint.com/Sites.Read.All

Take the access token and call the SPO API

You must ensure your app is registered with the correct permissions. In the case above the app must have Sites.Read.All for example.

user_11663071 · Answer

You could refer to this article to get access token:

https://global-sharepoint.com/sharepoint-online/in-4-steps-access-sharepoint-online-data-using-postman-tool/

Post https://accounts.accesscontrol.windows.net//tokens/OAuth/2

Body:

grant_type     client_credentials
client_id      
client_secret  
resource       00000003-0000-0ff1-ce00-000000000000/.sharepoint.com@

My test result:

SharePoint Rest API how to get Access Token?

2 Answers