Allow Facebook App ID/Secret verification with Options Framework

optionsframework_on_validate-example.php

/** OPTIONS FRAMEWORK - FACEBOOK VERIFICATION
/ ================================================================================ */

// Verify Facebook App ID and Secret
add_action( 'admin_notices', 'pr_facebook_verify' );
function pr_facebook_verify() {

	if ( get_option( 'fb_token' ) != '' ) {
	
		$screen = get_current_screen();
		$app_id = get_option( 'fb_appid_isvalid' );
		$secret = get_option( 'fb_secret_isvalid' );

		if ( !$app_id ) {
			if ( $screen->parent_base == 'themes' && $screen->id == 'appearance_page_options-framework' )
				add_settings_error( 'options-framework', 'bad_id', __( 'Facebook could not validate your Facebook App ID and Secret!', 'playground' ), 'error' );
			else
				echo "<div class='error'><p>".__( 'Facebook could not validate your Facebook App ID and Secret!', 'playground' )." <a href='".admin_url( 'themes.php?page=options-framework#of-option-facebookconnect' )."'>".__( 'Click here','playground' )."</a> to fix it.</p></div>";
		} else if ( !$secret ) {
			if ( $screen->parent_base == 'themes' && $screen->id == 'appearance_page_options-framework' )
				add_settings_error( 'options-framework', 'bad_secret', __( 'Facebook could not validate your Facebook App Secret!', 'playground' ), 'error' );
			else
				echo "<div class='error'><p>".__( 'Facebook could not validate your Facebook App Secret!', 'playground' )." <a href='".admin_url( 'themes.php?page=options-framework#of-option-facebookconnect' )."'>".__( 'Click here','playground' )."</a> to fix it.</p></div>";
		}
	}
}

add_action( 'optionsframework_after_validate', 'optionsframework_on_validate', 10, 2 );
function optionsframework_on_validate( $options ) {
	
	$app_id = $options['fb_app_id'];
	$secret = $options['fb_app_secret'];
	
	if ( $app_id || $secret ) {
		
		$object = json_decode( file_get_contents( "https://graph.facebook.com/{$app_id}" ) );
		
		if ( $object && isset( $object->link ) && strstr( $object->link, 'http://www.facebook.com/apps/application.php' ) ) {
			
			// App ID is valid
			update_option( 'fb_appid_isvalid', 1 );
			
			$response = wp_remote_get( "https://graph.facebook.com/oauth/access_token?client_id={$app_id}&client_secret={$secret}&grant_type=client_credentials" );
			if ( is_array( $response ) && strpos( $response['body'], 'access_token=' ) !== FALSE ) {
			
				// App secret is valid
				update_option( 'fb_secret_isvalid', 1 );
				// Store token
				update_option( 'fb_token', substr($response['body'], 13) );
				// Show successs alert
				add_settings_error( 'options-framework', 'connected', __( 'You have successfully connected to Facebook!', 'playground' ), 'updated fade' );
				
			} else {
			
				//App secret is NOT valid
				update_option( 'fb_secret_isvalid', 0 );
				// token = FALSE
				update_option( 'fb_token', 0 );
			}
			
		} else {
		
			// App ID is NOT valid, can't check for valid secret
			update_option( 'fb_appid_isvalid', 0 );
			update_option( 'fb_secret_isvalid', 0 );
			// token = FALSE
			update_option( 'fb_token', 0 );
		}

	} else {
		
		// Values are empty, clear all options
		update_option( 'fb_appid_isvalid', '' );
		update_option( 'fb_secret_isvalid', '' );
		update_option( 'fb_token', '' );
	}
	
	// Now all we have to do is check that `get_option( 'fb_token' )` is not blank or false before loading any Facebook API stuff.

}