Tcl

Facebook OAuth2 Access Token

See more Facebook Examples

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

load ./chilkat.dll

set success 0

# To further clarify, see OAuth 2.0 Authorization Flow

set oauth2 [new_CkOAuth2]

# This should match the Site URL configured for your Facebook APP, such as "http://localhost:3017/"
CkOAuth2_put_ListenPort $oauth2 3017

CkOAuth2_put_AuthorizationEndpoint $oauth2 "https://www.facebook.com/dialog/oauth"
CkOAuth2_put_TokenEndpoint $oauth2 "https://graph.facebook.com/oauth/access_token"

# Replace this with your actual App ID
CkOAuth2_put_ClientId $oauth2 "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.
CkOAuth2_put_Scope $oauth2 "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
CkOAuth2_put_CodeChallenge $oauth2 1
CkOAuth2_put_CodeChallengeMethod $oauth2 "S256"

# Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
set url [CkOAuth2_startAuth $oauth2]
if {[CkOAuth2_get_LastMethodSuccess $oauth2] != 1} then {
    puts [CkOAuth2_lastErrorText $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

puts "url = $url"

# Launch the default browser on the system and navigate to the url.
# The LaunchBrowser method was added in Chilkat v10.1.2.
set success [CkOAuth2_LaunchBrowser $oauth2 $url]
if {$success == 0} then {
    puts [CkOAuth2_lastErrorText $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

# Wait for the user to approve or deny authorization in the browser.
set numMsWaited 0
while {expr [$numMsWaited < 90000]  &&  [[CkOAuth2_get_AuthFlowState $oauth2] < 3]} {
    CkOAuth2_SleepMs $oauth2 100
    set numMsWaited [expr $numMsWaited + 100]
}

# 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 {[CkOAuth2_get_AuthFlowState $oauth2] < 3} then {
    CkOAuth2_Cancel $oauth2
    puts "No response from the browser!"
    delete_CkOAuth2 $oauth2
    exit
}

# 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 {[CkOAuth2_get_AuthFlowState $oauth2] == 5} then {
    puts "OAuth2 failed to complete."
    puts [CkOAuth2_failureInfo $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

if {[CkOAuth2_get_AuthFlowState $oauth2] == 4} then {
    puts "OAuth2 authorization was denied."
    puts [CkOAuth2_accessTokenResponse $oauth2]
    delete_CkOAuth2 $oauth2
    exit
}

if {[CkOAuth2_get_AuthFlowState $oauth2] != 3} then {
    puts "Unexpected AuthFlowState:[CkOAuth2_get_AuthFlowState $oauth2]"
    delete_CkOAuth2 $oauth2
    exit
}

puts "OAuth2 authorization granted!"
puts "Access Token = [CkOAuth2_accessToken $oauth2]"

delete_CkOAuth2 $oauth2