Add optional routable email check for email address element

This issue can be easily solved per element using a #pattern. I am not sure the webform should address this problem.

Should this issue be solved globally?

We could provide a code snippet (via a Recipe) that uses hook_element_info_alter() to add the email domain validation to all email elements. This snippet would be useful to everyone in the Drupal community because it would not be a webform specific solution.

I think this issue should be fixed using a more general solution and global solution.

Someone just posted a great workaround, which could be moved into a dedicated contrib module.

@see https://www.drupal.org/project/drupal/issues/2822142#comment-13833560

I think this should issue should be handled at a global level. Either a website's associated mail server can or can't handle routable addresses.

The solution provided by #2822142: Introduce a setting to make the top-level domain optional for email validation. will display an email validation error for fred@localhost.

I think custom code or a dedicated contrib module is the better solution.

Your decision as a maintainer, but I do agree that this would be a very useful feature to have. We frequently have cases where users mistype their mails (e.g. write .c instead of .ch, or forget the TLD entirely, or use dashes instead of ., I've seen everything). That's problematic as you then can't notify them and we often also have issues with integrations in other systems like mailchimp which causes such a subscription to fail with an error.

As for the implementation, you could do ->isValid($mail, new DNSCheckValidation()) which does a full DNS check to make sure the e-mail domain is valid.

If you decide to reopen then we could look into writing some tests as well.

Lets reopen this ticket.

Adding tests to it.
Cheers.

+++ b/tests/src/Functional/Element/WebformElementEmailTest.php
@@ -0,0 +1,43 @@
+    $this->assertRaw('A minimum second level domain is required.');
+
+    $edit = [
+      'email_no_routable_verification' => 'example01@example',
+      'email_with_routable_verification' => 'example02@example.com',
+    ];
+    $this->drupalPostForm('/webform/test_element_email', $edit, 'Submit');
+    $this->assertRaw("email_no_routable_verification: example01@example
+email_with_routable_verification: example02@example.com");

example.com specifically will actually not work anymore if you use the DNS verification thing as mentioned in my comment, because example.com does not have a MX record.

Whether or not we do use that approach, might make sense to use an e-mail address that would pass that check I think.

The patch looks okay.

Personally similar to my thoughts from #7, I would want this to be a global configuration setting under /admin/structure/webform/config/elements. In one place, a site admin can decide how email addresses are validated.

Attached is POC module that overrides the email.validator services and allows custom validation rules to be applied.

This approach to me makes the most sense since most sites would also like to validate user registration email addresses using the same logic.

This approach also validates email addresses entered via the admin UI.

Am I wrong to suggest that this should be handled via a dedicated contrib module?

@paulocs I really appreciate you taking a crack at the patch. While reviewing the patch, can't help but ask should this advanced email validation logic be a dedicated webform-only feature.

Hey Jacob.
No problem. I see that patch #14 must have some improvements as pointed on comment #12 and #16 if we do a DNS verification.

About #17, it is a good idea to have this verification in a separate module because other people will be able to use the DNS verification regardless webform is installed or not.
But I don't know how other popular webforms handle this verification. If they provide this functionality in core I assume that webform module should have this functionality as well.

If you decide to create a another module for that, I can help anyway.
Let's see what other people will say.

Cheers.

I don't have the bandwidth to create and maintain a new module. There are some similar modules available including https://www.drupal.org/project/email_validator

I agree that we need see what other people will say.

I really this email address DNS validation enhancements should be done at a global level via #17. I am going to close this ticket.