vikunja/docs/content/doc/development/notifications.md

date	title	toc	draft	menu
2021-02-07T19:26:34+02:00	Notifications	true	false	sidebar parent development

Notifications

Vikunjs provides a simple abstraction to send notifications per mail and in the database.

{{< table_of_contents >}}

Definition

Each notification has to implement this interface:

type Notification interface {
    ToMail() *Mail
    ToDB() interface{}
    Name() string
}

Both functions return the formatted messages for mail and database.

A notification will only be sent or recorded for those of the two methods which don't return nil. For example, if your notification should not be recorded in the database but only sent out per mail, it is enough to let the ToDB function return nil.

Mail notifications

A list of chainable functions is available to compose a mail:

mail := NewMail(). 
    // The optional sender of the mail message.
    From("test@example.com").
	// The optional receipient of the mail message. Uses the mail address of the notifiable if omitted.
    To("test@otherdomain.com").
	// The subject of the mail to send.
    Subject("Testmail").
	// The greeting, or "intro" line of the mail.
    Greeting("Hi there,").
	// A line of text
    Line("This is a line of text").
	// An action can contain a title and a url. It gets rendered as a big button in the mail.
	// Note that you can have only one action per mail.
	// All lines added before an action will appearr in the mail before the button, all lines 
	// added afterwards will appear after it.
    Action("The Action", "https://example.com").
	// Another line of text.
    Line("This should be an outro line").

If not provided, the from field of the mail contains the value configured in mailer.fromemail.

Database notifications

All data returned from the ToDB() method is serialized to json and saved into the database, along with the id of the notifiable, the name of the notification and a time stamp. If you don't use the database notification, the Name() function can return an empty string.

Creating a new notification

The easiest way to generate a mail is by using the mage dev:make-notification command.

It takes the name of the notification and the package where the notification will be created.

Notifiables

Notifiables can receive a notification. A notifiable is defined with this interface:

type Notifiable interface {
    // Should return the email address this notifiable has.
    RouteForMail() string
    // Should return the id of the notifiable entity
    RouteForDB() int64
}

The User type from the user package implements this interface.

Sending a notification

Sending a notification is done with the Notify method from the notifications package. It takes a notifiable and a notification as input.

For example, the email confirm notification when a new user registers is sent like this:

n := &EmailConfirmNotification{
    User:  update.User,
    IsNew: false,
}

err = notifications.Notify(update.User, n)
return

Testing

The mail package provides a Fake() method which you should call in the MainTest functions of your package. If it was called, no mails are being sent and you can instead assert they have been sent with the AssertSent method.

Example

Take a look at the pkg/user/notifications.go file for a good example.