PowerBuilder

Facebook OAuth2 Access Token

See more Facebook Examples

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

integer li_rc
integer li_Success
oleobject loo_Oauth2
string ls_Url
integer li_NumMsWaited

li_Success = 0

// To further clarify, see OAuth 2.0 Authorization Flow

loo_Oauth2 = create oleobject
li_rc = loo_Oauth2.ConnectToNewObject("Chilkat.OAuth2")
if li_rc < 0 then
    destroy loo_Oauth2
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// This should match the Site URL configured for your Facebook APP, such as "http://localhost:3017/"
loo_Oauth2.ListenPort = 3017

loo_Oauth2.AuthorizationEndpoint = "https://www.facebook.com/dialog/oauth"
loo_Oauth2.TokenEndpoint = "https://graph.facebook.com/oauth/access_token"

// Replace this with your actual App ID
loo_Oauth2.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.
loo_Oauth2.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
loo_Oauth2.CodeChallenge = 1
loo_Oauth2.CodeChallengeMethod = "S256"

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
ls_Url = loo_Oauth2.StartAuth()
if loo_Oauth2.LastMethodSuccess <> 1 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_Oauth2
    return
end if

Write-Debug "url = " + ls_Url

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
li_Success = loo_Oauth2.LaunchBrowser(ls_Url)
if li_Success = 0 then
    Write-Debug loo_Oauth2.LastErrorText
    destroy loo_Oauth2
    return
end if

// Wait for the user to approve or deny authorization in the browser.
li_NumMsWaited = 0
do while (li_NumMsWaited < 90000) AND (loo_Oauth2.AuthFlowState < 3)
    loo_Oauth2.SleepMs(100)
    li_NumMsWaited = li_NumMsWaited + 100
loop

// 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 loo_Oauth2.AuthFlowState < 3 then
    loo_Oauth2.Cancel()
    Write-Debug "No response from the browser!"
    destroy loo_Oauth2
    return
end if

// 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 loo_Oauth2.AuthFlowState = 5 then
    Write-Debug "OAuth2 failed to complete."
    Write-Debug loo_Oauth2.FailureInfo
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState = 4 then
    Write-Debug "OAuth2 authorization was denied."
    Write-Debug loo_Oauth2.AccessTokenResponse
    destroy loo_Oauth2
    return
end if

if loo_Oauth2.AuthFlowState <> 3 then
    Write-Debug "Unexpected AuthFlowState:" + string(loo_Oauth2.AuthFlowState)
    destroy loo_Oauth2
    return
end if

Write-Debug "OAuth2 authorization granted!"
Write-Debug "Access Token = " + loo_Oauth2.AccessToken


destroy loo_Oauth2