Using Gravity Forms gf_apply_filters() and gf_do_action() in Gravity Forms development

These two Gravity Forms functions are under-documented, but they're very powerful, so we have provided some additional information for Gravity Forms developers!

Using gf_apply_filters and gf_do_action

These two functions are powerful tools for creating dynamic, context-specific hooks in your Gravity Forms add-ons. They automatically generate multiple hook variations based on form IDs, field IDs, or other modifiers you provide.

What these functions do

Both gf_apply_filters() and gf_do_action() create cascading hooks that go from general to specific. For example, if you use a form ID modifier, the functions will trigger both a general hook (affecting all forms) and a form-specific hook (affecting only that form).

This pattern allows developers to:

• Hook into all forms with one callback
• Hook into specific forms with targeted callbacks
• Hook into specific fields within specific forms for precise control

gf_apply_filters()

Use gf_apply_filters() when you need to filter or modify data and want to provide both general and specific hook points for other developers.

Basic syntax

$filtered_value = gf_apply_filters( $filter_name_or_array, $value, ...$additional_args );

Parameters

• $filter (string|array): The filter name or an array containing the filter name and modifiers
• $value (mixed): The value to be filtered
• ...$args (mixed): Additional arguments to pass to filter callbacks (up to 10 supported)

Simple example

// Apply a general filter
$entry_meta = gf_apply_filters( 'gform_entry_meta', $entry_meta, $form );

This creates one filter: gform_entry_meta

Example with form ID modifier

// Apply both general and form-specific filters
$entry_meta = gf_apply_filters(
    array( 'gform_entry_meta', $form['id'] ),
    $entry_meta,
    $form
);

This creates two filters:

1. gform_entry_meta (general - affects all forms)
2. gform_entry_meta_5 (specific - affects only form ID 5)

Example with form and field ID modifiers

// Apply general, form-specific, and field-specific filters
$field_value = gf_apply_filters(
    array( 'gform_field_value', $form['id'], $field->id ),
    $value,
    $entry,
    $field
);

This creates three filters:

1. gform_field_value (all fields in all forms)
2. gform_field_value_5 (all fields in form 5)
3. gform_field_value_5_3 (only field 3 in form 5)

Hooking into gf_apply_filters

Developers can hook into any of the generated filter variations:

// Hook into all forms
add_filter( 'gform_entry_meta', 'my_general_callback', 10, 2 );


// Hook into specific form
add_filter( 'gform_entry_meta_5', 'my_form_specific_callback', 10, 2 );


// Hook into specific field in specific form
add_filter( 'gform_field_value_5_3', 'my_field_specific_callback', 10, 4 );


function my_field_specific_callback( $value, $entry, $field, $form ) {
    // Only runs for field 3 in form 5
    if ( $field->type === 'email' ) {
        $value = strtolower( $value );
    }
    return $value;
}

gf_do_action()

Use gf_do_action() when you want to trigger actions at specific points and provide both general and specific hook points for other developers.

Basic syntax

gf_do_action( $action_name_or_array, ...$args );

Parameters

• $action (string|array): The action name or an array containing the action name and modifiers
• ...$args (mixed): Arguments to pass to action callbacks (up to 10 supported)

Simple example

// Trigger a general action
gf_do_action( 'gform_after_submission', $entry, $form );

This triggers one action: gform_after_submission

Example with form ID modifier

// Trigger both general and form-specific actions
gf_do_action(
    array( 'gform_after_submission', $form['id'] ),
    $entry,
    $form
);

This triggers two actions:

1. gform_after_submission (general - all forms)
2. gform_after_submission_5 (specific - only form ID 5)

Example with form and field ID modifiers

// Trigger general, form-specific, and field-specific actions
gf_do_action(
    array( 'gform_field_validation', $form['id'], $field->id ),
    $result,
    $value,
    $form,
    $field
);

This triggers three actions:

1. gform_field_validation (all fields in all forms)
2. gform_field_validation_5 (all fields in form 5)
3. gform_field_validation_5_3 (only field 3 in form 5)

Hooking into gf_do_action

Developers can hook into any of the generated action variations:

// Hook into all forms
add_action( 'gform_after_submission', 'process_all_submissions', 10, 2 );


// Hook into specific form
add_action( 'gform_after_submission_5', 'process_contact_form', 10, 2 );


// Hook into specific field validation
add_action( 'gform_field_validation_5_3', 'validate_special_email', 10, 5 );


function validate_special_email( $result, $value, $form, $field, $entry ) {
    // Only runs for field 3 in form 5
    if ( strpos( $value, '@company.com' ) === false ) {
        $result['is_valid'] = false;
        $result['message'] = 'Please use your company email address.';
    }
}

Real-world examples from Gravity Forms

Entry detail page actions

// From entry_detail.php - trigger actions before displaying entry details
gf_do_action( array( 'gform_pre_entry_detail', $form['id'] ), $form, $lead );

Developers can hook in like:

// Process all entry detail pages
add_action( 'gform_pre_entry_detail', 'log_entry_views', 10, 2 );

// Process only form 5 entry detail pages
add_action( 'gform_pre_entry_detail_5', 'special_contact_processing', 10, 2 );

Order summary filtering

// From common.php - filter order summary data
$field_data = gf_apply_filters(
    array( 'gform_order_summary', $form['id'] ),
    $field_data,
    $form,
    $lead,
    $products,
    $format
);

Developers can filter like:

// Modify all order summaries
add_filter( 'gform_order_summary', 'add_tax_line', 10, 6 );

// Modify only form 3 order summaries
add_filter( 'gform_order_summary_3', 'add_shipping_discount', 10, 6 );

Field input filtering

// From common.php - filter field input HTML
$field_input = gf_apply_filters(
    array( 'gform_field_input', $form_id, $field->id ),
    '',
    $field,
    $value,
    $lead_id,
    $form_id
);

Developers can filter like:

// Modify all field inputs
add_filter( 'gform_field_input', 'add_custom_attributes', 10, 5 );

// Modify all fields in form 2
add_filter( 'gform_field_input_2', 'add_form_specific_classes', 10, 5 );

// Modify only field 4 in form 2
add_filter( 'gform_field_input_2_4', 'customize_email_field', 10, 5 );