Filtering submitted values

If you need to modify a submitted field value before it is processed, you may use the af/form/submission/value filter. This filter is applied to the raw input value of a field before it is formatted by ACF.

add_filter( 'af/form/submission/value', function ( $value, $field, $form, $args ) {
    // Restrict to a specific form
    if ( $form['key'] !== 'form_62bd15508b9c9' ) {
        return $value;
    }

    // Modify a value by field name
    if ( $field['name'] === 'first_name' ) {
        $value = ucfirst( $value );
    }

    // Modify a value by field key
    if ( $field['key'] === 'field_5e5e5e5e5e5e5' ) {
        $value = trim( $value );
    }

    return $value;
}, 10, 4 );

Filtering sub field values

Sub field values, such as those within a repeater, group, of flexible content field, do not individually pass through this filter. Instead, the parent field value is passed through the filter. If you need to modify sub field values, you will need to loop through the $value variable and apply your modifications to each sub field value.

Timing and related caveats

The af/form/submission/value filter fires before validation. Any custom validation rules added using the af/form/validate filter the access field values via the af_get_field() function will be affected by this filter.

Note that Advanced Forms validates fields in the AF()->submission['fields'] array whereas ACF core validates fields in the $_POST['acf'] array. This means that ACF's core validation will not be affected by the af/form/submission/value filter.

Validation is fired via AJAX so a modified value won't show in the form, even though it affects validation.

Custom validation conflicts

If you are using the af/form/validate action to enforce a specific value, and the af/form/submission/value filter is used to modify the value to something that is invalid, the validation will fail regardless of the user input. e.g;

add_filter( 'af/form/submission/value', function ( $value, $field, $form, $args ) {
    // Modify the value to something that is invalid
    if ( $field['name'] === 'first_name' ) {
        $value = 'bar';
    }

    return $value;
}, 10, 4 );

add_action( 'af/form/validate', function ( $form, $args ) {
    // Enforce a specific value
    if ( af_get_field( 'first_name' ) !== 'foo' ) {
        af_add_error( 'first_name', 'First name should be "foo"' );
    }
}, 10, 4 );

Modfying values based on other fields

This filter is executed before the Advanced Forms submission array is created. This means that it is not possible to use the af_get_field() function to get the value of another submitted field. Instead, you can access the raw values using their field keys from the $_POST['acf'] array. e.g;

add_filter( 'af/form/submission/value', function ( $value, $field, $form, $args ) {
    // Restrict to a specific form
    if ( $form['key'] !== 'form_62bd15508b9c9' ) {
        return $value;
    }

    // Check for the field we want to modify
    if ( $field['name'] === 'first_name' ) {

        // Only modify the value if another field value meets a condition
        if ( $_POST['acf']['field_5e5e5e5e5e5e5'] === 'foo' ) {
            $value = 'bar';
        }
    }

    return $value;
}, 10, 4 );