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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 417 Comments

  • 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 2.14
* @author David Smith <david@gravitywiz.com>
* @license GPL-2.0+
* @link https://gravitywiz.com/2012/09/19/better-inventory-with-gravity-forms/
* @copyright 2014 Gravity Wiz
*/
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' ) );
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()
) );
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', $index + 1 );
// Fetch entry from submission if available. Otherwise, get default/dynpop value.
if( isset( GFFormDisplay::$submission[ $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';
$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( $this->_args['input_id'] ) )
return "<div class=\"ginput_container\">{$this->_args['out_of_stock_message']}</div>";
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 );
extract( $atts ); // gives us $id, $input_id
return intval( self::get_field_values_sum( $id, $input_id ) );
}
public function shortcode_remaining( $output, $atts ) {
$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'] ) {
$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'];
}
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. Hi. I tried to use the code and: 1. I pasted code from”download code to function.php then 2 I’ve pasted code drom snippet to function php 4 I created a form with quantity field (separate with drop down list, id 9 (without .3) ) 5. I created pages – one with form, second with “remaining” and “sum” shortcodes. 6. I edited snippet in functions.php and in shortcodes. uff. ;-)

    so – I can choose quantity, it is correct in forms , but shortcodes still shows 50 (maximum) of remaining and 0 of purchased.

    I thought it was a mistake to input snippet (configuration) into “function php” so i used “code snippet” plugin and after pasting and activation – white screen of death… I was using demo installation at “gravitydemo.com”

    So where should I paste a snippet code? into functions php?

    Reply

    • OK. I see “code” and a “snippet code” “Code” should be pasted to “functions.php” and where should be pladed “snippet code”? I placed both in “functions .php” but it does not work.

      Shotrcode returns remaining 50 and sum 0. Id was correct (quantity) tested both – single 8.3 and standalone quantity “9” No changes when I “purchased” items – but in database I saw, that there was changes. Looks like snippet did not take data from database.

    • Ok just simple question – should it work properly with BOTH codes in “function.php” ? For me it is working “partially”

      Or is it necessary to place “main code” in function and a snippet in other place.

  3. I have used your inventory code and that is working perfect but i need to know one thing if the room is occupied then free for use then how can we re available that space for use ??

    Thanks K!

    Reply

  4. This snippet works great, thank you very much!

    Question: who gets the email when

    ‘enable_notifications’ => true

    , and is there any way to configure which email it goes to? I initially looked in Notifications for an Event but didn’t see an inventory related event in the drop down. Cheers!

    Reply

  5. Hi David,

    First of all: thanks for creating such usefull codes…!

    Regarding the question I had the shortcode: Shortcode: Display Number of Entries Left, you directed me to this shortcode. I installed it on my website and it first looked to be working fine.

    However in my case the following isn’t working. I have multiple forms for workshops (4). These forms all have a specific form id off course. Every workshop has it’s own limit of allowed participants (mostly 12). For this form I use the productfield with list of choices to add the amount of participants.

    When I use this snippet: new GW_Inventory( array( ‘form_id’ => 1, ‘field_id’ => 9, ‘stock_qty’ => 12, ‘out_of_stock_message’ => ‘Sorry, er is helaas geen plaats meer voor deze workshop. Zoek een andere workshop uit of neem contact met ons op voor de mogelijkheden’, ‘not_enough_stock_message’ => ‘Je wilde %1$s deelnemers aanmelden voor onze workshop. Er zijn maar %2$s plaatsen over.’, ‘approved_payments_only’ => false, ‘hide_form’ => false, ‘enable_notifications’ => true ) );

    it workes great for one workshop. But how do I make this work for all workshops? I tried creating multiple of above snippets and also took a look at your page https://gravitywiz.com/documentation/apply-class-based-snippet-different-forms/, but I can’t seem to figger it out.

    Can you please assist?

    Regards,

    Jorrit

    Reply

    • I’m using the shortcode [gravityforms action="remaining" id="1" input_id="2.3" limit="50"]

  6. Just wondering, if I have multiple product fields on the same page that all start with the same stock quantity, can I pass on multiple field ids at once in the initialization script?

    Thanks again!

    Reply

    • This snippet must be configured per field. You would just duplicate the configuration bit at the bottom and replace the field ID.

  7. Hi, Is there a way to use this snipped if my product field is set to the Radio Buttons field type. We have a form where users can select from up to 8 choices and I’d like to track inventory for each choice (ideally be able to set a different stock quantity for each choice).

    Is this possible? I’d be happy to pay for your time if the snippet would need to be modified. Thanks!

    Reply

  8. I used the plugin, but it does no longer work well, so I am interested in using your way. But Is there a way I can set this up for my client, so he will be able to adjust the quantity limits? I cannot give him access to the functions.php.

    $stock_qty the number of this item you have available.

    Thanx!

    Reply

    • Hi Kitty, the “stock_qty” does not need to be a static value. You can set it as a callable function which would allow you to retrieve the stock dynamically. Here’s an example where the quantity is fetched from a “stock” custom field on whatever post/page the form is embedded.

      http://snippi.com/s/sr3ccf4

    • Hi Peli, I’ve updated the article above with instructions on the available shortcodes with this snippet. You’ll want the “remaining” shortcode.

  11. Hello,

    I was wondering if there was an easy option to send an email when the max quantity has been reached instead of displaying the “out_of_stock_message” That email just has to have that same message saying the max. number has been reached but the person who is using the form should be able to submit.

    Thanks for your replay.

    Reply

    • Hi Marino, you can enable notifications via the “enable_notifications” parameter. If “hide_form” is set to false, the form will not be hidden.

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