How to use Gravity Forms gform_validation to ensure at least one of email or phone are entered - gravity-forms-plugin

Question

I'm a designer rather than a developer.
I'm using Gravity Forms. I have a simple Gravity Form:
[name]
[phone]
[email]
[message]
I'd like to ensure at least one of [phone] or [email] have been entered, rather than requiring both to be filled in.
Gravity Forms support say I can use gform_validation but I don't know how to build the code to validate the form such that if both [phone] and [email] are empty a message is displayed: please enter either phone or email.
Help appreciated.

Answer 1

In my opinion, it might be easier to do it this way:
Verify that one of phone or email inputs is filled by submitting the input data to a script. It could be JS or a PHP script. This can be done easily by using logical operators to check if both are empty.
Then use https://www.gravityhelp.com/documentation/article/gform_validation/#2-send-entry-data-to-third-party

Answer 2

For a singular form, using ID's to require atleast 1 of 2 fields being filled
This works great on smaller sites who only have 1 Gravity Form with an email field and phone field. Easily customizable. Most of the code is explained with comments.
<?php
// 1 = ID of form
add_filter( 'gform_validation_1', 'custom_validation' );
function custom_validation( $validation_result ) {
$form = $validation_result['form'];
// Our desired input fields
$phone = rgpost( 'input_6' );
$email = rgpost( 'input_7' );
// Fields that must be empty
if ( empty( $phone ) && empty( $email )) {
// Looping through the fields
foreach( $form['fields'] as &$field ) {
// Finds the field with ID of 7
// This is the field where the validation message will appear, can add multiple inbetween with ||-operator
if ( $field->id == '7' /*|| $field->id == '6'*/ ) {
$field->failed_validation = true;
$field->validation_message = 'Please enter either an email address or phone number.';
$validation_result['is_valid'] = false;
}
}
}
// Assign modified $form object back to the validation result
$validation_result['form'] = $form;
return $validation_result;
}
?>
Dynamic script that will run on all forms with input type="email" & input type="tel"
This works great on larger sites with multiple Gravity Forms. The script below will affect all Gravity Forms. Code is explained with comments.
<?php
add_filter( 'gform_validation', 'custom_validation' );
function custom_validation( $validation_result ) {
$form = $validation_result['form'];
// Finds current page
$current_page = rgpost( 'gform_source_page_number_' . $form['id'] ) ? rgpost( 'gform_source_page_number_' . $form['id'] ) : 1;
// Initiated when $current_page is true
if ( $current_page ) {
// Loops through all fields
foreach( $form['fields'] as &$field ) {
// Input types
$field_phone = $field["type"] == 'phone';
$field_email = $field["type"] == 'email';
// Accessing field value with rgpost()
$field_value = rgpost("input_{$field['id']}");
if ( $field_phone ) {
// Assigning the field value of field type phone
$field_phone_type = $field_value;
}
if ( $field_email ) {
// Assigning the field value of field type email
$field_email_type = $field_value;
// Only runs if theres both a field type email AND field type phone
if (isset( $field_email_type ) && isset( $field_phone_type )) {
// If both the email and phone fields are empty
if ( empty( $field_phone_type ) && empty( $field_email_type )) {
// Validation message is applied to $field_email field only - can be modified to be both
$validation_result['is_valid'] = false;
$field->failed_validation = true;
$field->validation_message = 'Please enter either an email address or phone number.';
}
}
}
}
}
// Assign modified $form back to the validation result
$validation_result['form'] = $form;
return $validation_result;
}
?>