Use PowerShell to Authenticate to AAD Then Call a Web API

Invoke-WebApiWithAadToken.ps1

### Load ADAL
Add-Type -Path "${env:ProgramFiles(x86)}\Microsoft SDKs\Azure\PowerShell\ServiceManagement\Azure\Services\Microsoft.IdentityModel.Clients.ActiveDirectory.dll"

# Set AAD client ID for the client app
$clientId         = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" 
$resourceAppIdURI = "https://TestWebApi01.azurewebsites.net"
$authority        = "https://login.windows.net/MyAadDirectory.onmicrosoft.com"

# Create Authentication Context tied to Azure AD Tenant
$authContext = New-Object "Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext" -ArgumentList $authority

# Acquire token http://www.cloudidentity.com/blog/2014/07/10/adal-v2-and-windows-integrated-authentication/
$authResult = $authContext.AcquireToken($resourceAppIdURI, $clientId, (New-Object Microsoft.IdentityModel.Clients.ActiveDirectory.UserCredential me@MyAadDirectory.com))

### Use the token to call the API
Invoke-RestMethod -Method Get -Uri https://TestWebApi01.azurewebsites.net/api/values -Headers @{"Authorization" = "Bearer $($authResult.AccessToken)"}