hidden.php

<?php
/*
Plugin Name: Contact Form 7 Modules: Hidden Fields
Plugin URI: https://katz.co/contact-form-7-hidden-fields/
Description: Add hidden fields to the popular Contact Form 7 plugin.
Author: Katz Web Services, Inc.
Author URI: http://www.katz.co
Version: 2.0.2
Text Domain: cf7_modules
Domain Path: languages
License: GPLv2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
*/

add_action('plugins_loaded', 'contact_form_7_hidden_fields', 11);

function contact_form_7_hidden_fields() {
	global $pagenow;
	if ( class_exists( 'WPCF7_Shortcode' ) || class_exists('WPCF7_FormTag') ) {
		if ( function_exists( 'wpcf7_add_form_tag' ) ) {
			wpcf7_add_form_tag( array( 'hidden', 'hidden*' ), 'wpcf7_hidden_shortcode_handler', true );
		} else {
			wpcf7_add_shortcode( array( 'hidden', 'hidden*' ), 'wpcf7_hidden_shortcode_handler', true );
		}
	} else {
		if ( $pagenow != 'plugins.php' ) {
			return;
		}

		add_action( 'admin_notices', 'contact_form_7_hidden_fields_error' );
		add_action( 'admin_enqueue_scripts', 'contact_form_7_hidden_fields_scripts' );
	}
}

function contact_form_7_hidden_fields_error() {
	$out = '<div class="error" id="messages"><p>';
	if ( @ file_exists( WP_PLUGIN_DIR . '/contact-form-7/wp-contact-form-7.php' ) ) {
		$out .= esc_html__( 'The Contact Form 7 is installed, but you must activate Contact Form 7 below for the Hidden Fields Module to work.', 'cf7_modules' );
	} else {
		$out .= esc_html__( 'The Contact Form 7 plugin must be installed for the Hidden Fields Module to work.', 'cf7_modules' );
		$install_url = esc_url_raw( admin_url( 'plugin-install.php?tab=plugin-information&plugin=contact-form-7&from=plugins&TB_iframe=true&width=600&height=550' ) );
		$out .= sprintf( ' <a href="%s" class="thickbox" title="Contact Form 7">%s</a>', $install_url, esc_html__( 'Install Now.', 'cf7_modules' ) );
	}
	$out .= '</p></div>';
	echo $out;
}

function contact_form_7_hidden_fields_scripts() {
	wp_enqueue_script('thickbox');
}

/**
** A base module for [hidden] and [hidden*]
**/

/* Shortcode handler */

add_filter('wpcf7_form_elements', 'wpcf7_form_elements_strip_paragraphs_and_brs');

/**
 * Strip paragraph tags being wrapped around the field
 * @param $form
 *
 * @return mixed
 */
function wpcf7_form_elements_strip_paragraphs_and_brs($form) {
	return preg_replace_callback( '/<p>(<input\stype="hidden"(?:.*?))<\/p>/ism', 'wpcf7_form_elements_strip_paragraphs_and_brs_callback', $form );
}

function wpcf7_form_elements_strip_paragraphs_and_brs_callback($matches = array()) {
	return "\n" . '<!-- CF7 Modules -->' . "\n" . '<div style=\'display:none;\'>' . str_replace( '<br>', '', str_replace( '<br />', '', stripslashes_deep( $matches[1] ) ) ) . '</div>' . "\n" . '<!-- End CF7 Modules -->' . "\n";
}

/**
** A base module for [hidden], [hidden*]
**/

/* Shortcode handler */

function wpcf7_hidden_shortcode_handler( $tag ) {

	if ( class_exists( 'WPCF7_FormTag' ) ) {
	    $tag = new WPCF7_FormTag( $tag );
	} else {
		$tag = new WPCF7_Shortcode( $tag );
	}

	if ( empty( $tag->name ) ) {
		return '';
	}

	$validation_error = wpcf7_get_validation_error( $tag->name );

	$class = wpcf7_form_controls_class( $tag->type, 'wpcf7-hidden' );

	if ( $validation_error ) {
		$class .= ' wpcf7-not-valid';
	}

	$class .= ' wpcf7-hidden';

	if ( 'hidden*' === $tag->type ) {
		$class .= ' wpcf7-validates-as-required';
	}

	$value = (string) reset( $tag->values );

	$placeholder = '';
	if ( $tag->has_option( 'placeholder' ) || $tag->has_option( 'watermark' ) ) {
		$placeholder = $value;
		$value       = '';
	}

	$default_value = $tag->get_default_option( $value );

	$value = contact_form_7_hidden_fields_fill_post_data( $value, $tag );

	// Post data hasn't filled yet. No arrays.
	if ( $default_value === $value ) {
		$value = contact_form_7_hidden_fields_fill_user_data( $value );
	}

	// Arrays get imploded.
	$value = is_array( $value ) ? implode( apply_filters( 'wpcf7_hidden_field_implode_glue', ', ' ), $value ) : $value;

	// Make sure we're using a string. Objects get JSON-encoded.
	if ( ! is_string( $value ) ) {
		$value = json_encode( $value );
	}

	$value = apply_filters( 'wpcf7_hidden_field_value', apply_filters( 'wpcf7_hidden_field_value_' . $tag->get_id_option(), $value ) );

	$value = wpcf7_get_hangover( $tag->name, $value );

	$atts = array(
		'type'        => 'hidden',
		'class'       => $tag->get_class_option( $class ),
		'id'          => $tag->get_id_option(),
		'name'        => $tag->name,
		'tabindex'    => $tag->get_option( 'tabindex', 'int', true ),
		'placeholder' => $placeholder,
		'value'       => $value,
	);

	$atts = wpcf7_format_atts( $atts );

	$html = sprintf( '<input %1$s />%2$s', $atts, $validation_error );

	return $html;
}

/**
 * Fill data based on user information.
 *
 * @param string $value Existing value, if any
 *
 * @return mixed
 */
function contact_form_7_hidden_fields_fill_user_data( $value ) {

	$return = $value;

	// Process user stuff
	if ( preg_match( '/user/ism', strtolower( trim( $value ) ) ) && is_user_logged_in() ) {

	    $current_user = wp_get_current_user();

		switch ( $value ) {
			case 'user_name':
				$return = $current_user->user_login;
				break;
			case 'user_id':
				$return = $current_user->ID;
				break;
			case 'caps':
				$return = $current_user->caps;
				break;
			case 'allcaps':
				$return = $current_user->allcaps;
				break;
			case 'user_roles':
				$return = $current_user->roles;
				break;
			default:
				// Gets the values for `user_email`, others that have `user_` prefix.
				if ( $current_user->has_prop( $value ) ) {
					$return = $current_user->get( $value );
				} else {
					// Define some other item in the WP_User object using the `user_[what you want to get]` format
					// This works for the `user_display_name` setting
					$user_key = preg_replace( '/user[_-](.+)/ism', '$1', $value );
					if ( $current_user->has_prop( $user_key ) ) {
						$return = $current_user->get( $user_key );
					}
				}
				break;
		}
	}

	return $return;
}

/**
 * Fill data based on user information.
 *
 * @param string $value Existing value, if any
 * @param WPCF7_Shortcode $tag Tag
 *
 * @return mixed
 */
function contact_form_7_hidden_fields_fill_post_data( $value = '', $tag ) {
	global $post;

	$return = $value;

	if ( is_object( $post ) ) {

		switch ( strtolower( trim( $value ) ) ) {
			case 'post_title':
			case 'post-title':
				$return = $post->post_title;
				break;
			case 'page_url':
			case 'post_url':
				$return = get_permalink( $post->ID );
				if ( empty( $return ) && isset( $post->guid ) ) {
					$return = $post->guid;
				}
				$return = esc_url( $return );
				break;
			case 'post_category':
				$categories = get_the_category( $post->ID );
				$catnames   = array();
				// Get the category names
				foreach ( $categories as $cat ) {
					$catnames[] = $cat->cat_name;
				}

				$return = implode( ', ', $catnames );
				break;
			case 'post_author_id':
				$return = $post->post_author;
				break;
			case 'post_author':
				$user   = get_userdata( $post->post_author );
				$return = $user->display_name;
				break;
			default:
				// You want post_modified? just use [hidden hidden-123 "post_modified"]
				if ( isset( $post->{ $value } ) ) {
					$return = $post->{ $value };
				}
				break;
		}

		if ( preg_match( '/^custom_field\-(.*?)$/ism', $value ) ) {
			$custom_field = preg_replace( '/custom_field\-(.*?)/ism', '$1', $value );
			$return       = get_post_meta( $post->ID, $custom_field, false ) ? get_post_meta( $post->ID, $custom_field, false ) : '';
		}
	}

	return $return;
}


/* Tag generator */

if ( is_admin() ) {
	add_action( 'admin_init', 'wpcf7_add_tag_generator_hidden', 30 );
}

function wpcf7_add_tag_generator_hidden() {

	if ( class_exists( 'WPCF7_TagGenerator' ) ) {

		$tag_generator = WPCF7_TagGenerator::get_instance();
		$tag_generator->add( 'hidden', _x( 'hidden', 'the name of the field button in CF7', 'cf7_modules' ), 'wpcf7_tg_pane_hidden' );

	}
}

function wpcf7_tg_pane_hidden( $contact_form, $args = '' ) {

	$args = wp_parse_args( $args, array() );

	$description = __( "Generate a form tag for a hidden field. For more details, see %s.", 'contact-form-7' );
	$desc_link   = wpcf7_link( 'https://wordpress.org/plugins/contact-form-7-modules/', __( 'the plugin page on WordPress.org', 'contact-form-7' ), array( 'target' => '_blank' ) );
	?>
    <div class="control-box">
        <fieldset>
            <legend><?php printf( esc_html( $description ), $desc_link ); ?></legend>

            <table class="form-table">
                <tbody>
                <tr>
                    <th scope="row"><label
                                for="<?php echo esc_attr( $args['content'] . '-name' ); ?>"><?php echo esc_html( __( 'Name', 'contact-form-7' ) ); ?></label>
                    </th>
                    <td><input type="text" name="name" class="tg-name oneline"
                               id="<?php echo esc_attr( $args['content'] . '-name' ); ?>"/></td>
                </tr>

                <tr>
                    <th scope="row"><label
                                for="<?php echo esc_attr( $args['content'] . '-id' ); ?>"><?php echo esc_html( __( 'ID attribute', 'contact-form-7' ) ); ?>
                            (<?php echo esc_html( __( 'optional', 'cf7_modules' ) ); ?>)</label></th>
                    <td><input type="text" name="id" class="idvalue oneline option"
                               id="<?php echo esc_attr( $args['content'] . '-id' ); ?>"/></td>
                </tr>
                <tr>
                    <th scope="row">
						<?php _e( 'Value', 'cf7_modules' ); ?>
                    </th>
                    <td>
                        <input type="text" name="values" class="oneline"/>
                        <div>
                            <input type="checkbox" name="watermark"
                                   class="option"/>&nbsp;<?php echo esc_html( __( 'Use this text as watermark?', 'cf7_modules' ) ); ?>
                        </div>
                    </td>
                </tr>
                <tr>
                    <th scope="row">
						<?php _e( 'Dynamic Values', 'cf7_modules' ); ?>
                    </th>
                    <td>
                        <span class="howto"
                              style="font-size:1em;"><?php _e( 'To use dynamic data from the post or page the form is embedded on, you can use the following values:', 'cf7_modules' ); ?></span>

                        <ul>
                            <li><?php _e( '<code>post_title</code>: The title of the post/page', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>post_url</code>: The URL of the post/page', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>post_category</code>: The categories the post is in, comma-separated', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>post_date</code>: The date the post/page was created', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>post_author</code>: The name of the author of the post/page', 'cf7_modules' ); ?></li>
                        </ul>
                        <span class="howto"><?php _e( 'The following values will be replaced if an user is logged in:', 'cf7_modules' ); ?></span>
                        <ul>
                            <li><?php _e( '<code>user_name</code>: User Login', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>user_id</code>: User ID', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>user_email</code>: User Email Address', 'cf7_modules' ); ?></li>
                            <li><?php _e( '<code>user_display_name</code>: Display Name (Generally the first and last name of the user)', 'cf7_modules' ); ?></li>
                        </ul>
                    </td>
                </tr>
                </tbody>
            </table>
        </fieldset>
    </div>

    <div class="insert-box">
        <input type="text" name="hidden" class="tag code" readonly="readonly" onfocus="this.select()"/>

        <div class="submitbox">
            <input type="button" class="button button-primary insert-tag"
                   value="<?php echo esc_attr( __( 'Insert Tag', 'contact-form-7' ) ); ?>"/>
        </div>

        <br class="clear"/>

        <p class="description mail-tag"><label
                    for="<?php echo esc_attr( $args['content'] . '-mailtag' ); ?>"><?php echo sprintf( esc_html( __( "To use the value input through this field in a mail field, you need to insert the corresponding mail-tag (%s) into the field on the Mail tab.", 'contact-form-7' ) ), '<strong><span class="mail-tag"></span></strong>' ); ?>
                <input type="text" class="mail-tag code hidden" readonly="readonly"
                       id="<?php echo esc_attr( $args['content'] . '-mailtag' ); ?>"/></label></p>
    </div>
	<?php
}