Access Sharepoint online using Azure AD app (Oauth Implicit grant flow)

I worked on a sample ps script that uses ADAL to achieve implicit grant flow and use the access token to access Sharepoint Online resource

Read more about authentication flows https://docs.microsoft.com/en-us/azure/active-directory/develop/authentication-flows-app-scenarios

Read more about implicit grant flows from https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-implicit-grant-flow

Steps

1.      1. Register an app in Azure AD https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-register-app

2.      Add client secret

3.      2. Add permission to Sharepoint

https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-configure-app-access-web-apis#add-permissions-to-access-web-apis

4.      3. Run the following in Windows Powershell ISE

Install the ADAL PS module using the below command

Install-Module -Name ADAL.PS

 Sample Script

$authority = "https://login.microsoftonline.com/tenant.onmicrosoft.com"

$resourceUrl = “https://tenant.sharepoint.com"

$clientId = "<<application Id>>"

$redirectUri = "https://login.microsoftonline.com/common/oauth2/nativeclient" # you should have marked the app as native client in Azure AD

$clientSecret = ConvertTo-SecureString "<<Client secret>>" -AsPlainText -Force

$tenantId="<<tenant GUID>"

$userID="<<Guid of the user>>"

$response = Get-ADALToken -Resource $resourceUrl  -UserId $userID -ClientId $clientId -UserIdType UniqueId   -Authority $authority -PromptBehavior: Auto -RedirectUri $redirectUri

$token = $response.AccessToken

$headers = @{}

$headers.Add("Accept","application/json")

$headers.Add("Authorization","Bearer $token")

$curl="https://tenant.sharepoint.com/_api/search/query?querytext='test'"

$response1 =  Invoke-RestMethod -Method Get -Uri $curl -Headers $headers -Verbose -ContentType application/json

$response1