It is rendered by bounding the context of a mailer and using a template engine.

For convenience, there is a correlation between the view mailer name and the template file name. It’s the translation of the name into a path: from Mailers::ForgotPassword to forgot_password.

The remaining part is made of multiple file extensions. The first is relative to the format and the latter is for the template engine.

For a given mailer named Mailers::ForgotPassword, there must be at least one template forgot_password.[format].[engine] under the mailers templates directory.

If we want to associate a different template to a mailer, we can use template.

Our view will look for lib/bookshelf/mailers/templates/send_password.* template.

This is a list of the supported engines. They are listed in order of higher precedence, for a given extension. For instance, if ERubis is loaded, it will be preferred over ERb to render .erb templates.

In order to use a different template engine we need to bundle the gem and to use the right file extension.

Templates are located in the default directory mailers/templates, located under an application’s directory lib/bookshelf, where bookshelf is the name of our application. If we want to customize this location, we can set a different value in Hanami::Mailer configuration.