Rust Requires Chilkat v10.1.2+

Facebook OAuth2 Access Token

See more Facebook Examples

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

// To further clarify, see OAuth 2.0 Authorization Flow

let oauth2 = chilkat::OAuth2::new();

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

oauth2.set_authorization_endpoint("https://www.facebook.com/dialog/oauth");
oauth2.set_token_endpoint("https://graph.facebook.com/oauth/access_token");

// Replace this with your actual App ID
oauth2.set_client_id("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.set_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.set_code_challenge(true);
oauth2.set_code_challenge_method("S256");

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
let Ok(url) = oauth2.start_auth() else {
    println!("{}", oauth2.last_error_text());
    return;
};

println!("url = {}", url);

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
if oauth2.launch_browser(&url).is_err() {
    println!("{}", oauth2.last_error_text());
    return;
}

// Wait for the user to approve or deny authorization in the browser.
let mut num_ms_waited = 0;
while (num_ms_waited < 90000) && (oauth2.auth_flow_state() < 3) {
    oauth2.sleep_ms(100);
    num_ms_waited = num_ms_waited + 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 oauth2.auth_flow_state() < 3 {
    let _ = oauth2.cancel();
    println!("No response from the browser!");
    return;
}

// 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.auth_flow_state() == 5 {
    println!("OAuth2 failed to complete.");
    println!("{}", oauth2.failure_info());
    return;
}

if oauth2.auth_flow_state() == 4 {
    println!("OAuth2 authorization was denied.");
    println!("{}", oauth2.access_token_response());
    return;
}

if oauth2.auth_flow_state() != 3 {
    println!("Unexpected AuthFlowState:{}", oauth2.auth_flow_state());
    return;
}

println!("OAuth2 authorization granted!");
println!("Access Token = {}", oauth2.access_token());