Custom EmailType

[trivialkettle]

Hi
my use case is to send an email to all registered users, my solution looks like this:

create SMTP Service

// override email delivery to set custom content
func notificationEmailOverrides(originalImplementation emaildelivery.SMTPInterface) emaildelivery.SMTPInterface {
	(*originalImplementation.GetContent) = func(input emaildelivery.EmailType, userContext supertokens.UserContext) (emaildelivery.EmailContent, error) {
		user := input.EmailVerification.User
		content := emaildelivery.EmailContent{
			Body:    notificationEmailBody,
			IsHtml:  true,
			Subject: notificationEmailSubject,
			ToEmail: user.Email,
		}
		return content, nil
	}

	return originalImplementation
}

// SMTP Service to send emails
var Email *emaildelivery.EmailDeliveryInterface

func foo() {
// ...
    // create SMTP service instance
    Email = emailverification.MakeSMTPService(emaildelivery.SMTPServiceConfig{
			Settings: smtpSettings,
			Override: notificationEmailOverrides,
		})
 // ...

    sendNotificationEmail(...)

// ...
}

func sendNotificationEmail(userId string, email string, tenantId string, userContext supertokens.UserContext) {
	// we abuse the email type EmailVerification here, because we need to set any type and there is no custom type yet
	input := emaildelivery.EmailType{EmailVerification: &emaildelivery.EmailVerificationType{
		User: emaildelivery.User{
			ID:    userId,
			Email: email,
		},
		EmailVerifyLink: "",
		TenantId:        tenantId,
	}}
	err := (*Email.SendEmail)(input, userContext)
	return err
}

As you can see in sendNotificationEmail i set EmailType to EmailVerification because it is not possible to specify a custom type.

Is there any better solution or is it possible to update EmailType like this:

type EmailType struct {
	EmailVerification *EmailVerificationType
	PasswordReset     *PasswordResetType
	PasswordlessLogin *PasswordlessLoginType
	Custom *CustomType
}

type CustomType struct {
	User       User
	Data       map[string]interface{}{} // or use pointer type
	TenantId string
}

Thanks

[DLzer]

The use-case you're presenting here is a major smell. Why are you trying to extend/piggyback on an authentication based email system to send out generalized notifications?

I would highly recommend creating an interface for your SMTP provider and passing that to ST for authentication based emails and creating a separate system for sending out generalized batched email notifications.

[trivialkettle]

Hi,
I see your point. On the otherhand, that would mean to copy paste and maintain the supertokens SMTP functions.

My usecase is: I have an invite only flow based on https://supertokens.com/blog/how-to-create-an-invite-only-auth-flow. Though I don't use email reset, but an customized invitation email. I cannot use passwordless, because the golang sdk does not support account linking. Probably I could abuse usermetadata to check if the user has changed the initial password and override the resetEmail function to customize the content.

Currently I do this:

func customEmailOverrides(originalImplementation emaildelivery.SMTPInterface) emaildelivery.SMTPInterface {
	// see https://supertokens.com/docs/platform-configuration/email-delivery/smtp-service/change-email-content
	(*originalImplementation.GetContent) = func(input emaildelivery.EmailType, userContext supertokens.UserContext) (emaildelivery.EmailContent, error) {
		// ...
	}

	return originalImplementation
}

func createSmtp(smtp *SmtpSettings) {
      var customSmtpService = &emaildelivery.TypeInput{}
      
      smtpSettings := emaildelivery.SMTPSettings{
      			Host: smtp.Host,
      			From: emaildelivery.SMTPFrom{
      				Name:  smtp.FromName,
      				Email: smtp.FromEmail,
      			},
      			Port:     smtp.Port,
      			Username: &smtp.User,
      			Password: smtp.Password,
      			Secure:   smtp.Secure,
      		}
      
      customSmtpService.Service = emailverification.MakeSMTPService(emaildelivery.SMTPServiceConfig{
      			Settings: smtpSettings,
      			Override: customEmailOverrides,
      		})
}
// ...

func sendEmail(userId string, email string, tenantId string, userContext supertokens.UserContext) error {
	// we abuse the email type EmailVerification here, because we need to set any type and there is no custom type yet
	input := emaildelivery.EmailType{EmailVerification: &emaildelivery.EmailVerificationType{
		User: emaildelivery.User{
			ID:    userId,
			Email: email,
		},
		EmailVerifyLink: "",
		TenantId:        tenantId,
	}}
	err := *customSmtpService.Service.SendEmail(input, userContext)
	return err
}

to send out generalized notifications?

Well there are also authentication related notifications, like your password was not changed for 60 days (wouldnot do this), or your JWT / API token is expiring, etc..