(Lianja) Get OAuth2 Access Token for Azure Registered App

Demonstrates how to get OAuth2 access token for an Azure Registered App from a desktop application or script. This example demonstrates the OAuth2 authorization flow.

This example requires Chilkat v10.1.2 or greater.

Chilkat Lianja Extension Download Chilkat Lianja Extension

// To further clarify, see OAuth 2.0 Authorization Flow

loOauth2 = createobject("CkOAuth2")

// This should be the port in the localhost callback URL for your app.  
// The callback URL would look like "http://localhost:3017/" if the port number is 3017.
loOauth2.ListenPort = 3017

// ----------------------------------------------------------------------------------------------------------
// The screenshot at the bottom of this page shows how we created the Azure App Registration for this example.
// ----------------------------------------------------------------------------------------------------------

// Note: The endpoint depends on the Azure App Registration.
// See How to Choose the Correct Endpoints for your Azure App Registration
loOauth2.AuthorizationEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/authorize"
loOauth2.TokenEndpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token"

// Replace these with actual values.
loOauth2.ClientId = "CLIENT_ID"

// This is for Require Proof Key for Code Exchange (PKCE)
// See OAuth2 PKCE Explained
loOauth2.CodeChallenge = .T.
loOauth2.CodeChallengeMethod = "S256"

// Provide a SPACE separated list of scopes.
// See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

// Important: To get a refresh token in the final response, ask for "offline_access" scope
loOauth2.Scope = "openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite"

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
lcUrl = loOauth2.StartAuth()
if (loOauth2.LastMethodSuccess <> .T.) then
    ? loOauth2.LastErrorText
    release loOauth2
    return
endif

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
llSuccess = loOauth2.LaunchBrowser(lcUrl)
if (llSuccess = .F.) then
    ? loOauth2.LastErrorText
    release loOauth2
    return
endif

// Wait for the user to approve or deny authorization in the browser.
lnNumMsWaited = 0
do while (lnNumMsWaited < 90000) and (loOauth2.AuthFlowState < 3)
    loOauth2.SleepMs(100)
    lnNumMsWaited = lnNumMsWaited + 100
enddo

// If the browser does not respond within the specified time, AuthFlowState will be:
// 
// 1: Waiting for Redirect � The OAuth2 background thread is waiting for the browser's redirect request.
// 2: Waiting for Final Response � The thread is awaiting the final access token response.
// In either case, cancel the background task initiated by StartAuth.

if (loOauth2.AuthFlowState < 3) then
    loOauth2.Cancel()
    ? "No response from the browser!"
    release loOauth2
    return
endif

// Check AuthFlowState to determine if authorization was granted, denied, or failed:
// 
// 3: Success � OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
// 4: Access Denied � OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
// 5: Failure � OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if (loOauth2.AuthFlowState = 5) then
    ? "OAuth2 failed to complete."
    ? loOauth2.FailureInfo
    release loOauth2
    return
endif

if (loOauth2.AuthFlowState = 4) then
    ? "OAuth2 authorization was denied."
    ? loOauth2.AccessTokenResponse
    release loOauth2
    return
endif

if (loOauth2.AuthFlowState <> 3) then
    ? "Unexpected AuthFlowState:" + str(loOauth2.AuthFlowState)
    release loOauth2
    return
endif

? "OAuth2 authorization granted!"
? "Access Token = " + loOauth2.AccessToken

// When the token is near expiration, your app can refresh as shown here:
// Refresh Expiring OAuth2 Access Token for Azure Registered App

// Get the full JSON response:
loJson = createobject("CkJsonObject")
loJson.Load(loOauth2.AccessTokenResponse)
loJson.EmitCompact = .F.

// The JSON response looks like this:

// {
//   "token_type": "Bearer",
//   "scope": "User.Read Mail.ReadWrite Mail.Send",
//   "expires_in": 3600,
//   "ext_expires_in": 0,
//   "access_token": "EwBAA8l6B...",
//   "refresh_token": "MCRMdbe...",
//   "id_token": "eyJ0eXA..."
// }

// If an "expires_on" member does not exist, then add the JSON member by
// getting the current system date/time and adding the "expires_in" seconds.
// This way we'll know when the token expires.
if (loJson.HasMember("expires_on") <> .T.) then
    loDtExpire = createobject("CkDateTime")
    loDtExpire.SetFromCurrentSystemTime()
    loDtExpire.AddSeconds(loJson.IntOf("expires_in"))
    loJson.AppendString("expires_on",loDtExpire.GetAsUnixTimeStr(.F.))
endif

? loJson.Emit()

// Save the JSON to a file for future requests.
loFac = createobject("CkFileAccess")
loFac.WriteEntireTextFile("qa_data/tokens/_myAzureApp.json",loJson.Emit(),"utf-8",.F.)

// This is a screenshot of how we created the Azure App for this example:
// 


release loOauth2
release loJson
release loDtExpire
release loFac