Ruby

Facebook OAuth2 Access Token

See more Facebook Examples

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

require 'chilkat'

success = false

# To further clarify, see OAuth 2.0 Authorization Flow

oauth2 = Chilkat::CkOAuth2.new()

# This should match the Site URL configured for your Facebook APP, such as "http://localhost:3017/"
oauth2.put_ListenPort(3017)

oauth2.put_AuthorizationEndpoint("https://www.facebook.com/dialog/oauth")
oauth2.put_TokenEndpoint("https://graph.facebook.com/oauth/access_token")

# Replace this with your actual App ID
oauth2.put_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.
oauth2.put_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
oauth2.put_CodeChallenge(true)
oauth2.put_CodeChallengeMethod("S256")

# Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
url = oauth2.startAuth()
if (oauth2.get_LastMethodSuccess() != true)
    print oauth2.lastErrorText() + "\n";
    exit
end

print "url = " + url + "\n";

# Launch the default browser on the system and navigate to the url.
# The LaunchBrowser method was added in Chilkat v10.1.2.
success = oauth2.LaunchBrowser(url)
if (success == false)
    print oauth2.lastErrorText() + "\n";
    exit
end

# Wait for the user to approve or deny authorization in the browser.
numMsWaited = 0
while (numMsWaited < 90000) and (oauth2.get_AuthFlowState() < 3)
    oauth2.SleepMs(100)
    numMsWaited = numMsWaited + 100
end

# 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 (oauth2.get_AuthFlowState() < 3)
    oauth2.Cancel()
    print "No response from the browser!" + "\n";
    exit
end

# 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 (oauth2.get_AuthFlowState() == 5)
    print "OAuth2 failed to complete." + "\n";
    print oauth2.failureInfo() + "\n";
    exit
end

if (oauth2.get_AuthFlowState() == 4)
    print "OAuth2 authorization was denied." + "\n";
    print oauth2.accessTokenResponse() + "\n";
    exit
end

if (oauth2.get_AuthFlowState() != 3)
    print "Unexpected AuthFlowState:" + oauth2.get_AuthFlowState().to_s() + "\n";
    exit
end

print "OAuth2 authorization granted!" + "\n";
print "Access Token = " + oauth2.accessToken() + "\n";