Lianja

Facebook OAuth2 Access Token

See more Facebook Examples

Demonstrates how to get a Facebook OAuth2 access token from a desktop application or script. Lianja

llSuccess = .F.

// To further clarify, see OAuth 2.0 Authorization Flow

loOauth2 = createobject("CkOAuth2")

// This should match the Site URL configured for your Facebook APP, such as "http://localhost:3017/"
loOauth2.ListenPort = 3017

loOauth2.AuthorizationEndpoint = "https://www.facebook.com/dialog/oauth"
loOauth2.TokenEndpoint = "https://graph.facebook.com/oauth/access_token"

// Replace this with your actual App ID
loOauth2.ClientId = "APP_ID"

// Set the Scope to a comma-separated list of permissions the app wishes to request.
// See https://developers.facebook.com/docs/facebook-login/permissions/ for a full list of permissions.
loOauth2.Scope = "public_profile,user_friends,email,user_posts,user_likes,user_photos"

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

// Begin the OAuth2 Authorization code 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

? "url = " + lcUrl

// 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


release loOauth2