How to get the access token to Azure API Management programmatically? - azure

Question

I'm trying to implement Azure Active Directory in my API Management instance using the Protect an API by using OAuth 2.0 with Azure Active Directory and API Management doc. The doc suggests that in order to get the access token I need to use the Developer Portal.
My problem is: An external application is going to communicate with API Management. Is there a way to omit the Developer Portal and get the access token programmatically?

Answer 1

It's a pain but thanks to Jos Lieben I am able to do it with this Powershell function
It's specifically for granting API access on behalf of the Org, but as you can see you can extract the commands to get and use the API token.
Original Author Link: https://www.lieben.nu/liebensraum/2018/04/how-to-grant-oauth2-permissions-to-an-azure-ad-application-using-powershell-unattended-silently/
Function Grant-OAuth2PermissionsToApp{
Param(
[Parameter(Mandatory=$true)]$Username, #global administrator username
[Parameter(Mandatory=$true)]$Password, #global administrator password
[Parameter(Mandatory=$true)]$azureAppId #application ID of the azure application you wish to admin-consent to
)
$secpasswd = ConvertTo-SecureString $Password -AsPlainText -Force
$mycreds = New-Object System.Management.Automation.PSCredential ($Username, $secpasswd)
$res = login-azurermaccount -Credential $mycreds
$context = Get-AzureRmContext
$tenantId = $context.Tenant.Id
$refreshToken = #($context.TokenCache.ReadItems() | where {$_.tenantId -eq $tenantId -and $_.ExpiresOn -gt (Get-Date)})[0].RefreshToken
$body = "grant_type=refresh_token&refresh_token=$($refreshToken)&resource=74658136-14ec-4630-ad9b-26e160ff0fc6"
$apiToken = Invoke-RestMethod "https://login.windows.net/$tenantId/oauth2/token" -Method POST -Body $body -ContentType 'application/x-www-form-urlencoded'
$header = #{
'Authorization' = 'Bearer ' + $apiToken.access_token
'X-Requested-With'= 'XMLHttpRequest'
'x-ms-client-request-id'= [guid]::NewGuid()
'x-ms-correlation-id' = [guid]::NewGuid()
}
$script:url = "https://main.iam.ad.ext.azure.com/api/RegisteredApplications/$azureAppId/Consent?onBehalfOfAll=true"
Invoke-RestMethod -Uri $url -Headers $header -Method POST -ErrorAction Stop
}