Email does not support relative links since there is no implicit host. Therefore all links inside of emails must be fully qualified URLs. All path helpers are now deprecated. When removed, the error will give early indication to developers to use `*_url` methods instead.
Currently if a developer uses a `*_path` helper, their tests and `mail_view` will not catch the mistake. The only way to see the error is by sending emails in production. Preventing sending out emails with non-working path's is the desired end goal of this PR.
Currently path helpers are mixed-in to controllers (the ActionMailer::Base acts as a controller). All `*_url` and `*_path` helpers are made available through the same module. This PR separates this behavior into two modules so we can extend the `*_path` methods to add a Deprecation to them. Once deprecated we can use this same area to raise a NoMethodError and add an informative message directing the developer to use `*_url` instead.
The module with warnings is only mixed in when a controller returns false from the newly added `supports_relative_path?`.
Paired @sgrif & @schneems
Adds `config.action_mailer.preview_enabled`
This allows mail previewing to be enabled easily in non-development
environments such as staging. The default is set to true for development
so no changes should be required to existing Rails applications.
The mail preview path can still be configured using the existing
`config.action_mailer.preview_path` configuration option.
Adding this avoids devs from having to do stuff like:
https://gist.github.com/lengarvey/fa2c9bd6cdbeba96526a
Update actionmailer/CHANGELOG with new configuration.
Update configuring guide with new configuratation.
Add `config.action_mailer.preview_path` to configuring guide.
Only config.autoload_paths is frozen, so add the preview_path
to ActiveSupport::Dependencies.autoload_paths directly in an
after_initialize block. Also protect against a blank preview_path
being added to autoload_paths which can cause a serious slowdown
as Dir[] tries to load all *_preview.rb files under /
Fixes#13372
