Merge Tag Modifier Gravity Forms

Erik van Beek · Oct 14, 2017 ·

Do you know you can add functionality to your Gravity Forms Merge Tags. This can come in handy, for example when you want to show a field input capitalized or you want to replace certain values in the field.

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Create a Merge Tag modifier for uppercase
Sanatize title merge tag modifier (sanitize_title)
Sanitize file name modifier (sanitize_file_name)
URL encode merge tag modifier

Create a Merge Tag modifier for uppercase

Take for example that you want to show a certain Merge Tag value in capital letters. A simple way to do that is to add a Gravity Forms Merge Tag modifier to your functions.php.

add_filter( 'gform_merge_tag_filter', function ( $value, $merge_tag, $modifier, $field, $raw_value ) {
if ( $merge_tag != 'all_fields' && $modifier == 'gwp_uppercase' ) {
$value = strtoupper ( $value );
}
 
return $value;
}, 10, 5 );

You can see we do different things in the PHP code:

add a filter to the gform_merge_tag_filter hook
check if it's not used in the all_fields Merge Tag from Gravity Forms (since this is a unique merge tag to output all the data in a table, we don't want to attach our modifier to that one)
check if the modifier is gwp_uppercase
do something with the value that is passed (this is the value that the visitor filled in in the specific field you refer to with the modifier)
in our case: we use the PHP standard function strtoupper to make all the letters uppercase

How to use your uppercase Merge Tag modifier?

After adding your fresh PHP code to your functions.php file in your theme or child theme, you can use the gwp_uppercase modifier to output Merge Tag values in capital letters. Use it like this:

{Your first field:1:gwp_uppercase}

Sanatize title merge tag modifier (sanitize_title)

The sanitize_title function from WordPress is also a useful modifier of your values.

add_filter( 'gform_merge_tag_filter', function ( $value, $merge_tag, $modifier, $field, $raw_value ) {
if ( $merge_tag != 'all_fields' && $modifier == 'gwp_sanitize_title' ) {
$value = sanitize_title( $value );
}
 
return $value;
}, 10, 5 );

Use {field 1:1:gwp_sanitize_title} to sanitize the input of field 1.

Sanitize file name modifier (sanitize_file_name)

Sanitizes a filename, replacing whitespace with dashes. Removes special characters that are illegal in filenames on certain operating systems and special characters requiring special escaping to manipulate at the command line. Replaces spaces and consecutive dashes with a single dash. Trims period, dash and underscore from beginning and end of filename. It is not guaranteed that this function will return a filename that is allowed to be uploaded.

add_filter( 'gform_merge_tag_filter', function ( $value, $merge_tag, $modifier, $field, $raw_value ) {
if ( $merge_tag != 'all_fields' && $modifier == 'gwp_sanitize_file_name' ) {
$value = sanitize_file_name( $value );
}
 
return $value;
}, 10, 5 );

Use {field 1:1:gwp_sanitize_file_name} to sanitize the file name of field 1.

URL encode merge tag modifier

Returns a string in which all non-alphanumeric characters except -_. have been replaced with a percent (%) sign followed by two hex digits and spaces encoded as plus (+) signs. It is encoded the same way that the posted data from a WWW form is encoded, that is the same way as in application/x-www-form-urlencoded media type.

add_filter( 'gform_merge_tag_filter', function ( $value, $merge_tag, $modifier, $field, $raw_value ) {
if ( $merge_tag != 'all_fields' && $modifier == 'gwp_url_encode' ) {
$value = urlencode( $value );
}
 
return $value;
}, 10, 5 );

Use {field 1:1:gwp_url_encode} to URL encode the value of field 1.

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