Custom Registered FIelds Plugin

custom-register-fields.php

<?php
/*
Plugin Name: Custom Register Fields
Plugin URI: http://www.lcavanagh.bluehoststaff.com/
Description: Add first name, last name and job title.
Author: Luke Cavanagh
Version: 1.0
Author URI: http://www.lcavanagh.bluehoststaff.com/
GNU General Public License, Free Software Foundation <http://creativecommons.org/licenses/GPL/2.0/>
*/

//1. Add a new form element...
add_action( 'register_form', 'custom_register_form' );
function custom_register_form() {

    $first_name = ( ! empty( $_POST['first_name'] ) ) ? trim( $_POST['first_name'] ) : '';
    $last_name = ( ! empty( $_POST['last_name'] ) ) ? trim( $_POST['last_name'] ) : '';
    $job_title = ( ! empty( $_POST['job_title'] ) ) ? trim( $_POST['job_title'] ) : '';

        ?>
        <p>
            <label for="first_name"><?php _e( 'First Name', 'mydomain' ) ?><br />
                <input type="text" name="first_name" id="first_name" class="input" value="<?php echo esc_attr( wp_unslash( $first_name ) ); ?>" size="25" /></label>
        </p>
        <p>
          <label for="last_name"><?php _e( 'Last Name', 'mydomain' ) ?><br />
              <input type="text" name="last_name" id="last_name" class="input" value="<?php echo esc_attr( wp_unslash( $last_name ) ); ?>" size="25" /></label>
        </p>
        <p>
            <label for="job_title"><?php _e( 'Job Title', 'mydomain' ) ?><br />
                <input type="text" name="job_title" id="job_title" class="input" value="<?php echo esc_attr( wp_unslash( $job_title ) ); ?>" size="25" /></label>
        </p>
        <?php
    }

    //2. Add validation. In this case, we make sure first_name is required.
    add_filter( 'registration_errors', 'custom_registration_errors', 10, 3 );
    function custom_registration_errors( $errors, $sanitized_user_login, $user_email ) {

        if ( empty( $_POST['first_name'] ) || ! empty( $_POST['first_name'] ) && trim( $_POST['first_name'] ) == '' ) {
            $errors->add( 'first_name_error', __( '<strong>ERROR</strong>: You must include a first name.', 'mydomain' ) );
        }
        if ( empty( $_POST['last_name'] ) || ! empty( $_POST['last_name'] ) && trim( $_POST['last_name'] ) == '' ) {
            $errors->add( 'last_name_error', __( '<strong>ERROR</strong>: You must include a last name.', 'mydomain' ) );
        }
        if ( empty( $_POST['job_title'] ) || ! empty( $_POST['job_title'] ) && trim( $_POST['job_title'] ) == '' ) {
            $errors->add( 'job_title_error', __( '<strong>ERROR</strong>: You must include a job title.', 'mydomain' ) );
        }

        return $errors;
    }

    //3. Finally, save our extra registration user meta.
    add_action( 'user_register', 'custom_user_register' );
    function custom_user_register( $user_id ) {
        if ( ! empty( $_POST['first_name'] ) ) {
            update_user_meta( $user_id, 'first_name', trim( $_POST['first_name'] ) );
        }
        if ( ! empty( $_POST['last_name'] ) ) {
            update_user_meta( $user_id, 'last_name', trim( $_POST['last_name'] ) );
        }
        if ( ! empty( $_POST['job_title'] ) ) {
            update_user_meta( $user_id, 'job_title', trim( $_POST['job_title'] ) );
        }
    }

    add_action( 'show_user_profile', 'custom_show_extra_profile_fields' );
    add_action( 'edit_user_profile', 'custom_show_extra_profile_fields' );

    function custom_show_extra_profile_fields( $user ) { ?>

        <h3>Extra profile information</h3>

        <table class="form-table">

            <tr>
                <th><label for="job_title">Job Title</label></th>

                <td>
                    <input type="text" name="job_title" id="job_title" value="<?php echo esc_attr( get_the_author_meta( 'job_title', $user->ID ) ); ?>" class="regular-text" /><br />
                    <span class="description">Please enter your Job Title.</span>
                </td>
            </tr>

        </table>
    <?php }

add_action( 'personal_options_update', 'custom_save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'custom_save_extra_profile_fields' );

function custom_save_extra_profile_fields( $user_id ) {

    if ( !current_user_can( 'edit_user', $user_id ) )
        return false;

    /* Copy and paste this line for additional fields. Make sure to change 'job_title' to the field ID. */
    update_usermeta( absint( $user_id ), 'job_title', wp_kses_post( $_POST['job_title'] ) );
}