(Ruby) Microsoft Graph OAuth2 Client Credentials Grant Flow

Demonstrates how to get a Microsoft Graph access token using the Client Credentials Grant Flow.

You can use the OAuth 2.0 client credentials grant specified in RFC 6749, sometimes called two-legged OAuth, to access web-hosted resources by using the identity of an application. This type of grant is commonly used for server-to-server interactions that must run in the background, without immediate interaction with a user. These types of applications are often referred to as daemons or service accounts.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

http = Chilkat::CkHttp.new()

req = Chilkat::CkHttpRequest.new()
req.AddParam("client_secret","CLIENT_SECRET")
req.AddParam("client_id","CLIENT_ID")
# Don't know if the scopes valid for the client credentials grant are different than the scopes for the 3-legged Authorization Code Grant...
req.AddParam("scope","https://graph.microsoft.com/.default")
req.AddParam("grant_type","client_credentials")

# Use your own tenant ID, for example 4d8fdd66-66d1-43b0-ae5c-e31b4b7de5cd
url = "https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token"
# resp is a CkHttpResponse
resp = http.PostUrlEncoded(url,req)
if (http.get_LastMethodSuccess() != true)
    print http.lastErrorText() + "\n";
    exit
end

statusCode = resp.get_StatusCode()
print "Response status code = " + statusCode.to_s() + "\n";

json = Chilkat::CkJsonObject.new()
json.Load(resp.bodyStr())

json.put_EmitCompact(false)
print json.emit() + "\n";

# Sample successful output:

# {
#   "token_type": "Bearer",
#   "expires_in": 3599,
#   "ext_expires_in": 3599,
#   "access_token": "eyJ0eX...K0jOERg"
# }

if (statusCode == 200)
    json.WriteFile("qa_data/tokens/msGraphClientCredentialsToken.json")
    print "Success." + "\n";
else
    print "Failed." + "\n";
end