Disable membership unless users have agreed to Terms of Service (requires Register Helper).

pmpro_require_tos.php

<?php

/**
 * Disable membership unless users have agreed to Terms of Service (requires Register Helper).
 *
 *  - Adds a ToS checkbox and link to the user's profile page.
 *  - Overrides membership if users haven't agreed to updated ToS.
 *  - Filters non-member text if users haven't agreed to ToS.
 *  - Resets ToS user meta when ToS page is updated.
 */

/**
 * Register Helper Fields
 */
function my_pmprorh_init_require_tos() {

	if ( ! function_exists( 'pmprorh_add_registration_field' ) ) {
		return;
	}

	$fields = array();

	$tospage = pmpro_getOption( "tospage" );

	if ( empty( $tospage ) ) {
		return;
	}

	$tos_link = get_permalink( $tospage );
	$label    = "I agree to the <a href={$tos_link} target=_blank>Terms of Service</a>.";

	// Terms of Service Checkbox in Profile
	$fields[] = new PMProRH_Field( 'pmpro_tos_checked', 'checkbox', array(
		'label'   => $label,
		'profile' => true
	) );

	foreach ( $fields as $field ) {
		pmprorh_add_registration_field( 'just_profile', $field );
	}
}

add_action( 'init', 'my_pmprorh_init_require_tos' );

/**
 * Disable membership if ToS isn't accepted.
 */
function my_pmpro_has_membership_access_filter_require_tos( $hasaccess, $post, $user, $levels ) {

	global $pmpro_tos_check;

	// Only continue if user already has access.
	if ( ! $hasaccess || empty( $levels ) ) {
		$pmpro_tos_checked = false;
		return $hasaccess;
	}

	$tos_checked = get_user_meta( $user->ID, 'pmpro_tos_checked', true );
	$pmpro_tos_check = true;

	return $tos_checked;
}

add_filter( 'pmpro_has_membership_access_filter', 'my_pmpro_has_membership_access_filter_require_tos', 10, 4 );

/**
 * Change non-member text when user hasn't agreed to ToS.
 */
function my_pmpro_non_member_text_filter_require_tos( $text ) {

	global $current_user, $pmpro_tos_check;

	$tos_checked = get_user_meta( $current_user->ID, 'pmpro_tos_checked', true );

	if ( ! $tos_checked && $pmpro_tos_check ) {
		$text = 'You must agree to the Terms of Service before accessing this content.';
	}

	return $text;
}

add_filter( 'pmpro_non_member_text_filter', 'my_pmpro_non_member_text_filter_require_tos' );

/**
 * Reset ToS user meta when ToS page is updated.
 */
function my_post_updated_require_tos( $post_id, $post_after, $post_before ) {

	global $wpdb;

	// Only continue if PMPro is loaded.
	if ( ! function_exists( 'pmpro_getOption' ) ) {
		return;
	}

	$tospage = pmpro_getOption( "tospage" );

	if ( ! empty( $tospage ) && $post_id == $tospage && $post_after->post_content != $post_before->post_content ) {
		$sql = "UPDATE {$wpdb->usermeta} SET meta_value = '' WHERE meta_key = 'pmpro_tos_checked'";
		$wpdb->query( $sql );
	}

}

add_filter( 'post_updated', 'my_post_updated_require_tos', 10, 3 );