so much

internal/mailer/mailer.go

@@ -0,0 +1,96 @@
+package mailer
+
+import (
+	"bytes"
+	"embed"
+	"html/template"
+	"log"
+	// "time"
+
+	"github.com/wneessen/go-mail"
+)
+
+//go:embed "templates"
+var templateFS embed.FS
+
+type Mailer struct {
+	dialer *mail.Client
+	sender string
+}
+
+func New(host string, port int, username, password, sender string) Mailer {
+	// Initialize a new mail.Dialer instance with the given SMTP server settings. We
+	// also configure this to use a 5-second timeout whenever we send an email.
+	dialer, err := mail.NewClient(host,
+		mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(mail.TLSMandatory),
+		mail.WithUsername(username), mail.WithPassword(password),
+	)
+	if err != nil {
+		log.Fatalf("failed to deliver mail: %s", err)
+	}
+
+	// dialer. = 5 * time.Second
+	// Return a Mailer instance containing the dialer and sender information.
+	return Mailer{
+		dialer: dialer,
+		sender: sender,
+	}
+}
+
+// Define a Send() method on the Mailer type. This takes the recipient email address
+// as the first parameter, the name of the file containing the templates, and any
+// dynamic data for the templates as an interface{} parameter.
+func (m Mailer) Send(recipient, templateFile string, data interface{}) error {
+	// Use the ParseFS() method to parse the required template file from the embedded
+	// file system.
+	tmpl, err := template.New("email").ParseFS(templateFS, "templates/"+templateFile)
+	if err != nil {
+		return err
+	}
+
+	// Execute the named template "subject", passing in the dynamic data and storing the
+	// result in a bytes.Buffer variable.
+	subject := new(bytes.Buffer)
+	err = tmpl.ExecuteTemplate(subject, "subject", data)
+	if err != nil {
+		return err
+	}
+
+	// Follow the same pattern to execute the "plainBody" template and store the result
+	// in the plainBody variable.
+	plainBody := new(bytes.Buffer)
+	err = tmpl.ExecuteTemplate(plainBody, "plainBody", data)
+	if err != nil {
+		return err
+	}
+
+	// And likewise with the "htmlBody" template.
+	htmlBody := new(bytes.Buffer)
+	err = tmpl.ExecuteTemplate(htmlBody, "htmlBody", data)
+	if err != nil {
+		return err
+	}
+
+	// Use the mail.NewMessage() function to initialize a new mail.Message instance.
+	// Then we use the SetHeader() method to set the email recipient, sender and subject
+	// headers, the SetBody() method to set the plain-text body, and the AddAlternative()
+	// method to set the HTML body. It's important to note that AddAlternative() should
+	// always be called *after* SetBody().
+	msg := mail.NewMsg()
+	msg.SetAddrHeader("To", recipient)
+	msg.SetAddrHeader("From", m.sender)
+	msg.SetGenHeader("Subject", subject.String())
+	msg.SetBodyString("text/plain", plainBody.String())
+	msg.AddAlternativeString("text/html", htmlBody.String())
+
+	// Call the DialAndSend() method on the dialer, passing in the message to send. This
+	// opens a connection to the SMTP server, sends the message, then closes the
+	// connection. If there is a timeout, it will return a "dial tcp: i/o timeout"
+	// error.
+	err = m.dialer.DialAndSend(msg)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

internal/mailer/templates/user_welcome.tmpl

@@ -0,0 +1,35 @@
+{{define "subject"}}Welcome to Digitale Partei Österreich!{{end}}
+
+{{define "plainBody"}}
+Hi,
+
+Thanks for signing up for a Digitale Partei Österreich account. We're excited to have you on board!
+For future reference, your user ID number is {{.ID}}.
+
+Your activation token is {{.token}}
+
+Thanks,
+
+The DigitalePartei Team
+{{end}}
+
+{{define "htmlBody"}}
+<!doctype html>
+<html>
+
+<head>
+    <meta name="viewport" content="width=device-width" />
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+</head>
+
+<body>
+    <p>Hi,</p>
+    <p>Thanks for signing up for a Digitale Partei Österreich account. We're excited to have you on board!</p>
+    <p>For future reference, your user ID number is {{.ID}}.</p>
+    <p>Your activation token is {{.token}}</p>
+    <p>Thanks,</p>
+    <p>The DigitalePartei Team</p>
+</body>
+
+</html>
+{{end}}