How to Work with Emails during Development

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How to Work with Emails during Development

When developing an application which sends email, you will often not want to actually send the email to the specified recipient during development. If you are using the default Symfony mailer, you can achieve this through configuration settings without having to make any changes to your application's code at all. There are two main choices when it comes to handling email during development: (a) disabling the sending of email altogether or (b) sending all email to a specific address (with optional exceptions).

Disabling Sending

You can disable sending email by setting the disable_delivery option to true, which is the default value used by Symfony in the test environment (email messages will continue to be sent in the other environments):

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# config/packages/test/swiftmailer.yaml
swiftmailer:
    disable_delivery: true

Sending to a Specified Address(es)

You can also choose to have all email sent to a specific address or a list of addresses, instead of the address actually specified when sending the message. This can be done via the delivery_addresses option:

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# config/packages/dev/swiftmailer.yaml
swiftmailer:
    delivery_addresses: ['dev@example.com']

Now, suppose you're sending an email to recipient@example.com in a controller:

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public function index($name, \Swift_Mailer $mailer)
{
    $message = (new \Swift_Message('Hello Email'))
        ->setFrom('send@example.com')
        ->setTo('recipient@example.com')
        ->setBody(
            $this->renderView(
                'HelloBundle:Hello:email.txt.twig',
                ['name' => $name]
            )
        )
    ;
    $mailer->send($message);

    return $this->render(...);
}

In the dev environment, the email will instead be sent to dev@example.com. Swift Mailer will add an extra header to the email, X-Swift-To, containing the replaced address, so you can still see who it would have been sent to.

Note

In addition to the to addresses, this will also stop the email being sent to any CC and BCC addresses set for it. Swift Mailer will add additional headers to the email with the overridden addresses in them. These are X-Swift-Cc and X-Swift-Bcc for the CC and BCC addresses respectively.

Sending to a Specified Address but with Exceptions

Suppose you want to have all email redirected to a specific address, (like in the above scenario to dev@example.com). But then you may want email sent to some specific email addresses to go through after all, and not be redirected (even if it is in the dev environment). This can be done by adding the delivery_whitelist option:

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# config/packages/dev/swiftmailer.yaml
swiftmailer:
    delivery_addresses: ['dev@example.com']
    delivery_whitelist:
       # all email addresses matching these regexes will be delivered
       # like normal, as well as being sent to dev@example.com
       - '/@specialdomain\.com$/'
       - '/^admin@mydomain\.com$/'

In the above example all email messages will be redirected to dev@example.com and messages sent to the admin@mydomain.com address or to any email address belonging to the domain specialdomain.com will also be delivered as normal.

Caution

The delivery_whitelist option is ignored unless the delivery_addresses option is defined.

Viewing from the Web Debug Toolbar

You can view any email sent during a single response when you are in the dev environment using the web debug toolbar. The email icon in the toolbar will show how many emails were sent. If you click it, a report will open showing the details of the sent emails.

If you're sending an email and then immediately redirecting to another page, the web debug toolbar will not display an email icon or a report on the next page.

Instead, you can set the intercept_redirects option to true in the dev environment, which will cause the redirect to stop and allow you to open the report with details of the sent emails.

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# config/packages/dev/web_profiler.yaml
web_profiler:
    intercept_redirects: true

Tip

Alternatively, you can open the profiler after the redirect and search by the submit URL used on the previous request (e.g. /contact/handle). The profiler's search feature allows you to load the profiler information for any past requests.

Tip

In addition to the features provided by Symfony, there are applications that can help you test emails during application development, like MailCatcher and MailHog.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.
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