Gravity Wiz

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Better Inventory with Gravity Forms

Gravity Forms does not support the concept of inventory out of the box. This snippet provides an easy method for setting up simple, one-off inventory limits on a per field basis.

Last updated | Written by 509 Comments

  • October 18, 2019: Fixed issue where field groups were not correctly limited on submission.

  • October 10, 2019: Fixed issue where Calculated Product fields were still added to order summary after their inventory was exhausted.

  • March 19, 2019: Fixed issue where remaining shortcode did not always target correct instance of Better Inventory.

  • November 17, 2018: Added support for fetching prepopulated values when limiting by field group.

  • April 26, 2018: Updated snippet for Gravity Forms 2.3; snippet now requires 2.3.

  • May 31, 2017: Updated "remaining" shortcode to correctly limit by field groups and approved payments flag.

  • January 27, 2017: Fixed bug with approved_payments_only parameter where entries with no payment were counting towards all inventory limits.

  • January 21, 2017: Added support for automatically limiting GP Limit Date-enabled Date fields and paired with an inventory input (via field_group parameter) so that days with exhausted inventory or not available.

  • January 17, 2017: Updated "remaining" shortcode to dynamically retrieve the limit for the specified form and field.

  • March 23, 2016: Added support for specifying "stock_qty" parameter as a function. Allows for dynamically setting the stock_qty during runtime.

  • March 15, 2016: Updated paid status to "Paid" from "Approved" to work with GF Payment Add-on framework.

  • October 5, 2014: Added support for "remaining" action on [gravityforms] shortcode.

  • October 1, 2014: Added support for "sum" action on [gravityforms] shortcode.

  • November 11, 2012: Fixed issue where database prefix was not applied via $wpdb->prefix.

Show All Updates

Let’s dive into the code first.

Show CodeDownload Code
<?php
/**
* Gravity Wiz // Gravity Forms // Better Inventory with Gravity Forms
*
* Implements the concept of "inventory" with Gravity Forms by allowing the specification of a limit determined by the
* sum of a specific field, typically a quantity field.
*
* @version 2.20
* @author David Smith <david@gravitywiz.com>
* @license GPL-2.0+
* @link http://gravitywiz.com/better-inventory-with-gravity-forms/
*/
class GW_Inventory {
public $_args;
public function __construct( $args ) {
$this->_args = $this->parse_args( $args );
add_action( 'init', array( $this, 'init' ) );
}
public function init() {
// make sure we're running the required minimum version of Gravity Forms
if( ! property_exists( 'GFCommon', 'version' ) || ! version_compare( GFCommon::$version, '1.8', '>=' ) ) {
return;
}
add_filter( "gform_pre_render_{$this->_args['form_id']}", array( $this, 'limit_by_field_values' ) );
add_filter( "gform_validation_{$this->_args['form_id']}", array( $this, 'limit_by_field_values_validation' ) );
// check 'field_group' for date fields; if found, limit based on exhausted inventory days.
if( ! empty( $this->_args['field_group'] ) ) {
add_filter( "gpld_limit_dates_options_{$this->_args['form_id']}", array( $this, 'limit_date_fields' ), 10, 2 );
}
// add 'sum' action for [gravityforms] shortcode
add_filter( 'gform_shortcode_sum', array( $this, 'shortcode_sum' ), 10, 2 );
add_filter( 'gform_shortcode_remaining', array( $this, 'shortcode_remaining' ), 10, 2 );
add_action( 'gwinv_before_get_sum', array( $this, 'before_get_sum' ) );
add_action( 'gwinv_after_get_sum', array( $this, 'after_get_sum' ) );
add_filter( 'gform_product_info', array( $this, 'handle_calculated_product_fields' ), 10, 3 );
if( $this->_args['enable_notifications'] ) {
$this->enable_notifications();
}
}
public function parse_args( $args ) {
$args = wp_parse_args( $args, array(
'form_id' => false,
'field_id' => false,
'input_id' => false,
'stock_qty' => false,
'out_of_stock_message' => __( 'Sorry, this item is out of stock.' ),
'not_enough_stock_message' => __( 'You ordered %1$s of this item but there are only %2$s of this item left.' ),
'approved_payments_only' => false,
'hide_form' => false,
'enable_notifications' => false,
'field_group' => array()
) );
/**
* @var $stock_qty
* @var $field_group
*/
extract( $args );
if( ! $stock_qty && isset( $limit ) ) {
$args['stock_qty'] = $limit;
unset( $args['limit'] );
}
if( isset( $limit_message ) ) {
$args['out_of_stock_message'] = $limit_message;
unset( $args['limit_message'] );
}
if( isset( $validation_message ) ) {
$args['not_enough_stock_message'] = $validation_message;
unset( $args['validation_message'] );
}
if( ! $args['input_id'] ) {
$args['input_id'] = $args['field_id'];
unset( $args['field_id'] );
}
if( $field_group && ! is_array( $field_group ) ) {
$args['field_group'] = array( $field_group );
}
return $args;
}
public function enable_notifications() {
if( ! class_exists( 'GW_Notification_Event' ) ) {
_doing_it_wrong( 'GW_Inventory::$enable_notifications', __( 'Inventory notifications require the \'GW_Notification_Event\' class.' ), '1.0' );
} else {
$event_slug = "gwinv_out_of_stock_{$this->_args['input_id']}";
$event_name = GFForms::get_page() == 'notification_edit' ? $this->get_notification_event_name() : __( 'Event name is only populated on Notification Edit view; saves a DB call to get the form on every ' );
$this->_notification_event = new GW_Notification_Event( array(
'form_id' => $this->_args['form_id'],
'event_name' => $event_name,
'event_slug' => $event_slug,
'trigger' => array( $this, 'notification_event_listener' )
) );
}
}
public function limit_by_field_values( $form ) {
if( $this->is_in_stock() ) {
return $form;
}
if( $this->_args['hide_form'] ) {
add_filter( "gform_get_form_filter_{$form['id']}", array( $this, 'get_out_of_stock_message' ) );
} else if( empty( $this->_args['field_group'] ) ) {
add_filter( 'gform_field_input', array( $this, 'hide_field' ), 10, 2 );
}
return $form;
}
public function limit_by_field_values_validation( $validation_result ) {
$input_id = $this->_args['input_id'];
$limit = $this->get_stock_quantity();
$validation_message = $this->_args['not_enough_stock_message'];
$form = $validation_result['form'];
$exceeded_limit = false;
foreach( $form['fields'] as &$field ) {
if( $field['id'] != intval( $input_id ) ) {
continue;
}
$requested_qty = rgpost( 'input_' . str_replace( '.', '_', $input_id ) );
$field_sum = $this->get_sum();
if( rgblank( $requested_qty ) || $field_sum + $requested_qty <= $limit ) {
continue;
}
$exceeded_limit = true;
$stock_left = $limit - $field_sum >= 0 ? $limit - $field_sum : 0;
$field['failed_validation'] = true;
$field['validation_message'] = sprintf( $validation_message, $requested_qty, $stock_left );
}
if( $exceeded_limit && ! empty( $this->_args['field_group'] ) ) {
foreach( $form['fields'] as &$field ) {
if( in_array( $field->id, $this->_args['field_group'] ) ) {
$field['failed_validation'] = true;
$field['validation_message'] = sprintf( $validation_message, $requested_qty, $stock_left );
}
}
}
$validation_result['form'] = $form;
$validation_result['is_valid'] = ! $validation_result['is_valid'] ? false : ! $exceeded_limit;
return $validation_result;
}
public function limit_by_field_group( $query, $form_id, $input_id ) {
global $wpdb;
if( $input_id != $this->_args['input_id'] ) {
return $query;
}
$form = GFAPI::get_form( $form_id );
$join = $where = array();
foreach( $this->_args['field_group'] as $index => $field_id ) {
$field = GFFormsModel::get_field( $form, $field_id );
$alias = sprintf( 'fgld%d', $index + 1 );
// Fetch entry from submission if available. Otherwise, get default/dynpop value.
if( rgpost( 'gform_submit' ) == $form_id ) {
$value = $field->get_value_save_entry( GFFormsModel::get_field_value( $field ), $form, null, null, null );
} else {
$value = $field->get_value_default_if_empty( GFFormsModel::get_parameter_value( $field->inputName, array(), $field ) );
}
$join[] = "\nINNER JOIN {$wpdb->prefix}gf_entry_meta {$alias} ON em.entry_id = {$alias}.entry_id";
$where[] = $wpdb->prepare( "CAST( {$alias}.meta_key as unsigned ) = %d AND {$alias}.meta_value = %s ", $field_id, $value );
}
$query['join'] .= implode( "\n", $join );
$query['where'] .= sprintf( "\n AND %s", implode( "\nAND ", $where ) );
return $query;
}
public function limit_date_fields( $options, $form ) {
global $wpdb;
foreach( $form['fields'] as $field ) {
if( ! in_array( $field->id, $this->_args['field_group'] ) || $field->get_input_type() != 'date' || $field->dateType != 'datepicker' ) {
continue;
}
$query = self::get_sum_query( $field->formId, $this->_args['input_id'] );
if( $this->_args['approved_payments_only'] ) {
$query = $this->limit_by_approved_payments_only( $query );
}
if( ! empty( $this->_args['field_group'] ) ) {
// add our Date field to the front of the array so we can reliably target it when replacing the queries below
array_unshift( $this->_args['field_group'], $field->id );
$this->_args['field_group'] = array_unique( $this->_args['field_group'] );
$query = $this->limit_by_field_group( $query, $field->formId, $this->_args['input_id'] );
}
$regex = sprintf( '/(CAST\( fgld1.meta_key as unsigned \) = %d) AND fgld1.meta_value = \'(?:[\w\d]*)\'/', $field->id );
preg_match( $regex , $query['where'], $match );
if( ! empty( $match ) ) {
list( $search, $replace ) = $match;
$query['where'] = str_replace( $search, $replace, $query['where'] );
}
$query['select'] = 'SELECT sum( em.meta_value ) as total, fgld1.meta_value as date';
$query['group_by'] = 'GROUP BY date';
$query['having'] = sprintf( 'HAVING total >= %d', $this->get_stock_quantity() );
$sql = implode( "\n", $query );
$results = $wpdb->get_results( $sql );
foreach( $results as $result ) {
$options[ $field->id ]['exceptionsMode'] = 'disable';
if ( ! is_array( $options[ $field->id ]['exceptions'] ) ) {
$options[ $field->id ]['exceptions'] = array();
}
$options[ $field->id ]['exceptions'][] = date( 'm/d/Y', strtotime( $result->date ) );
}
}
return $options;
}
public function get_stock_quantity() {
$stock = $this->_args['stock_qty'];
if( is_callable( $stock ) ) {
$stock = call_user_func( $stock );
}
return $stock;
}
public function is_in_stock() {
$count = $this->get_sum();//self::get_field_values_sum( $this->_args['form_id'], $this->_args['input_id'] );
return $count < $this->get_stock_quantity();
}
public function hide_field( $field_content, $field ) {
if( $field['id'] == intval( $this->_args['input_id'] ) ) {
$quantity_input = '';
// GF will default to a quantity of 1 if it can't find the input for a Quantity field.
if ( $field->type === 'quantity' ) {
$quantity_input = sprintf( '<input type="hidden" name="input_%d_%d" value="0" />', $field->formId, $field->id );
}
return sprintf( '<div class="ginput_container">%s%s</div>', $this->_args['out_of_stock_message'], $quantity_input );
}
return $field_content;
}
public function notification_event_listener() {
// really is no better hook to use to send custom notifications just yet
add_filter( "gform_confirmation_{$this->_args['form_id']}", array( $this, 'send_out_of_stock_notifications' ), 10, 3 );
}
public function send_out_of_stock_notifications( $return, $form, $entry ) {
// if product is still in stock or the entry is spam, don't sent notification
if( $this->is_in_stock() || $entry['status'] == 'spam' )
return $return;
// if product is out of stock and no qty of the product is in current order, assume that out of stock notifications have already been sent
$requested_qty = intval( rgar( $entry, (string) $this->_args['input_id'] ) );
if( $requested_qty <= 0 )
return $return;
$this->_notification_event->send_notifications( $this->_notification_event->get_event_slug(), $form, $entry );
return $return;
}
public function get_notification_event_name() {
$form = GFAPI::get_form( $this->_args['form_id'] );
$field = GFFormsModel::get_field( $form, $this->_args['input_id'] );
$event_name = sprintf( __( '%s: Out of Stock' ), GFCommon::get_label( $field ) );
return $event_name;
}
public function shortcode_sum( $output, $atts ) {
$atts = shortcode_atts( array(
'id' => false,
'input_id' => false
), $atts );
/**
* @var $id
* @var $input_id
*/
extract( $atts ); // gives us $id, $input_id
return intval( self::get_field_values_sum( $id, $input_id ) );
}
public function shortcode_remaining( $output, $atts ) {
/**
* @var $id
* @var $input_id
* @var $limit
*/
$atts = shortcode_atts( array(
'id' => false,
'input_id' => false,
'limit' => false,
), $atts );
extract( $atts ); // gives us $id, $input_id
if( $input_id == $this->_args['input_id'] && $id == $this->_args['form_id'] ) {
$limit = $limit ? $limit : $this->get_stock_quantity();
$remaining = $limit - intval( $this->get_sum() );
$output = max( 0, $remaining );
}
return $output;
}
public function get_sum() {
if( $this->_args['approved_payments_only'] ) {
add_filter( 'gwinv_query', array( $this, 'limit_by_approved_payments_only' ) );
}
if( ! empty( $this->_args['field_group'] ) ) {
add_filter( 'gwinv_query', array( $this, 'limit_by_field_group' ), 10, 3 );
}
$sum = self::get_field_values_sum( $this->_args['form_id'], $this->_args['input_id'] );
remove_filter( 'gwinv_query', array( $this, 'limit_by_approved_payments_only' ) );
remove_filter( 'gwinv_query', array( $this, 'limit_by_field_group' ) );
return $sum;
}
public function limit_by_approved_payments_only( $query ) {
$valid_statuses = array( 'Approved' /* old */, 'Paid', 'Active' );
$query['where'] .= sprintf( ' AND ( e.payment_status IN ( %s ) OR e.payment_status IS NULL )', self::prepare_strings_for_mysql_in_statement( $valid_statuses ) );
return $query;
}
public function get_out_of_stock_message() {
return $this->_args['out_of_stock_message'];
}
/**
* Calculated Product fields limited by their default quantity should be excluded from the order summary.
*
* Since their value is calculated post submission, they function uniquely from other product fields.
*
* @param $order
* @param $form
* @param $entry
*
* @return mixed
*/
public function handle_calculated_product_fields( $order, $form, $entry ) {
foreach( $order['products'] as $field_id => $product ) {
// Check for if target input ID is for the current field and is targeting a Product field default quantity input (i.e. 1.3).
if( $field_id != intval( $this->_args['input_id'] ) || rgar( explode( '.', $this->_args['input_id'] ), 1 ) != '3' ) {
continue;
}
$field = GFAPI::get_field( $form, $field_id );
if( $field->get_input_type() !== 'calculation' ) {
continue;
}
if( ! $this->is_in_stock() ) {
unset( $order['products'][ $field_id ] );
}
}
return $order;
}
public static function get_field_values_sum( $form_id, $input_id ) {
global $wpdb;
$query = self::get_sum_query( $form_id, $input_id );
$sql = implode( "\n", $query );
$result = $wpdb->get_var( $sql );
return intval( $result );
}
public static function get_sum_query( $form_id, $input_id, $suppress_filters = false ) {
global $wpdb;
$query = array(
'select' => 'SELECT sum( em.meta_value )',
'from' => "FROM {$wpdb->prefix}gf_entry_meta em",
'join' => "INNER JOIN {$wpdb->prefix}gf_entry e ON e.id = em.entry_id",
'where' => $wpdb->prepare( "
WHERE em.form_id = %d
AND em.meta_key = %s
AND e.status = 'active'\n",
$form_id, $input_id
)
);
if( class_exists( 'GF_Partial_Entries' ) ) {
$query['where'] .= "and em.entry_id NOT IN( SELECT entry_id FROM {$wpdb->prefix}gf_entry_meta WHERE meta_key = 'partial_entry_id' )";
}
if( ! $suppress_filters ) {
$query = apply_filters( 'gwlimitbysum_query', $query, $form_id, $input_id );
$query = apply_filters( 'gwinv_query', $query, $form_id, $input_id );
$query = apply_filters( "gwinv_query_{$form_id}", $query, $form_id, $input_id );
$query = apply_filters( "gwinv_query_{$form_id}_{$input_id}", $query, $form_id, $input_id );
}
return $query;
}
public static function prepare_strings_for_mysql_in_statement( $strings ) {
$wrapped = array();
foreach( $strings as $string ) {
$wrapped[] = sprintf( '"%s"', $string );
}
return implode( ', ', $wrapped );
}
}
class GWLimitBySum extends GW_Inventory { }
view raw gw-gravity-forms-inventory.php hosted with ❤ by GitHub

How do I install this snippet?

Easy peasy. Just copy and paste the code above into your theme's functions.php file.

Do I need to modify this snippet to work with my form?

You don’t have to modify the snippet itself. Just the parameters with which you initialize it.

<?php
new GW_Inventory( array(
'form_id' => 363,
'field_id' => 2.3,
'stock_qty' => 20,
'out_of_stock_message' => 'Sorry, there are no more tickets!',
'not_enough_stock_message' => 'You ordered %1$s tickets. There are only %2$s tickets left.',
'approved_payments_only' => false,
'hide_form' => false,
'enable_notifications' => true
) );

Parameters

  • $form_id the ID of the form you are working with.
  • $field_id the ID of your product or quantity field. If using a Single Product field, you’ll need to specify the quantity input ID which will always be {field ID}.3 (ie if the field ID is 12, the quantity input ID will be 12.3). If using a separate Quantity field, simply specify the field ID.
  • $stock_qty the number of this item you have available.
  • $out_of_stock_message the message which should be displayed to users when the product limit has been reached. You can get fancy with this and add HTML as well. Be sure to escape any double quotes with a backslash. Here’s a more advanced example:
    $sum_limit_message = '<div style="border: 1px solid #e6db55; background-color: #FFFFE0; padding: 10px;">Sorry, this show is sold out.</div>';
    Better Inventory: Limit Message
  • $not_enough_stock_message the message which should be displayed on the field if the limit has not been reached, but the user’s requested quantity would exceed the product limit.
    Better Inventory: Limit Validation Message
  • $approved_payments_only true/false indicate whether all submissions for this field should be counted against the limit or only submissions with an approved payment. You’ll want to be careful here when using PayPal Standard due to the delay between the form submission and the payment being approved. It could lead to users exceeding the limit.
  • $hide_form by default this snippet will only hide the field when the limit has been reached. If you would rather hide the entire form, set this to true.
  • $enable_notifications enable the ability to create notifications that are sent when the stock of a product (or any configured field) has been exhausted

Shortcodes

  • Remaining
    Show the quantity remaining for the specified input and limit. [gravityforms action="remaining" id="1" input_id="2.3" limit="50"]

  • Sum
    Show the current sum of quantities ordered for this field across all entries. [gravityforms action="sum" id="1" input_id="2.3"]

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Comments

  1. Sharon Sparkes says

    Hi I’m new to gravityforms in the past I’ve used wufoo, formstack, and form assembly. I this snippet was so important to me because my organization runs limited capacity events every year and out limit is even more critical this year with Covid-19 protocols in place.

    We have had a few guests who were able to pay and checkout (authorize.net) when there were not enough tickets for the time slot. They recieved the message “You ordered 4 of this item but there are only 1 of this item left.” However they were still charged through Authorize.net, but they did not show up in our Gravity Froms entrees list and did not receive a receipt. Is there a way to make sure those who are attempting to order a time slot that is not available are not charged?

    Reply

    • Ryan Donovan says

      Hello Stephen, This is just a snippet that requires configuration at the bottom. You don’t have to modify the snippet itself. Just the parameters with which you initialize it. Check out our help article here for some snippet troubleshooting.

  3. Rachel Clark says

    Hi there, I’m using this snippet to track entries for an online art exhibition as we have a maximum number of entries allowed. I’m pretty new to php, can you advise me what I change the class ‘GW_Inventory’ to as I’m getting an error? Do I create a class for the form and target this instead? Also, if this is not a paying entry, can I just remove the line: ‘approved_payments_only’ => false,

    Thanks! Rachel

    Reply

    • Samuel Bassah says

      Hi Rachel,

      You’ll first have to copy and paste the code with the Class into your function.php file, then add the configuration with the parameters as seen in the documentation, below the code. Also, do not remove the approved payment parameter, but instead, leave it as approved_payments_only’ => false, if payment will not be received.

      In case you’re still having difficulties setting it up, please reply with the error message are you getting?

      Best,

  4. Carter Lovelace says

    Hey Wiz-team!

    This looks perfect for a form I’m working on for a client’s website. I have a Pro license for GravityPerks and was hoping to install this functionality using that, but I don’t see it listed in the GP “Install Perks” window.

    Any help would be greatly appreciated!

    Reply

  6. J says

    How can you reset the stock quantity once it reaches 0? I don’t want the user to have to create a new form and edit the functions file.

    Reply

    • Ryan Donovan says

      Hello J, Would you like this to happen immediately or after a day? You can reset the inventory daily via the following steps:

      Add a Date field to your form. Set the Default Value of this field to use the {date_mdy} merge tag. Set the Visibility of this field to Hidden. Add a “field_group” parameter to your snippet configuration where the “1” is the ID of your Date field: “field_group” => array( 1 ) This will make the inventory specific to the desired product and the current date.

    • Jack says

      Thanks for the reply! Ideally, it should happen after 1 week. I’m trying to create an even registration with limited seat numbers and have it reset after the event occurs or manually.

    • Samuel Bassah says

      Hi Jack,

      You can reset the stock quantity by trashing the submitted entries. So when you remove an entry, the number of seats available will be increased by 1.

      I hope this helps.

      Best,

    • Alistair Mckenzie says

      I think this is what i require, i.e. several products that can be ordered on the day and when qty reached sold out but also need it to reset every day. I am a novice developer ( meaning im a designer with a little knowledge lol). Can you be more specific on how i would add this to the above snippet ( i.e. can you write it for me please) Thanks in advance for any help

    • Scott Buchmann says

      Hi Alistair,

      Assuming the ID for your Date field is 2, you would add the parameter like this:

      new GW_Inventory( array(
    'form_id'     => 363,
    'field_id'    => 2.3,
    'stock_qty'   => 20,
    'field_group' => array( 2 ),
) );

      The Date field can correspond to any date you’d like, including delivery date. What the field group does is tie the inventory to the specific date selected. So each date has its own stock quantity.

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