feat: initial commit

2025-03-31 16:17:35 +01:00
commit 6719f8a61a
91 changed files with 7119 additions and 0 deletions
@@ -0,0 +1,16 @@
+package mailer
+
+import "embed"
+
+const (
+	FromName            = "LK API"
+	maxRetries          = 3
+	UserWelcomeTemplate = "user_activation.tmpl"
+)
+
+//go:embed "templates"
+var FS embed.FS
+
+type Client interface {
+	Send(templateFile, username, email string, data any, isDevEnv bool) (int, error)
+}
@@ -0,0 +1,67 @@
+package mailer
+
+import (
+	"bytes"
+	"fmt"
+	"text/template"
+	"time"
+
+	"github.com/sendgrid/sendgrid-go"
+	"github.com/sendgrid/sendgrid-go/helpers/mail"
+)
+
+type SendGridMailer struct {
+	fromEmail string
+	apiKey    string
+	client    *sendgrid.Client
+}
+
+func NewSendGrid(apiKey, fromEmail string) *SendGridMailer {
+	client := sendgrid.NewSendClient(apiKey)
+	return &SendGridMailer{
+		fromEmail: fromEmail,
+		apiKey:    apiKey,
+		client:    client,
+	}
+}
+
+func (s *SendGridMailer) Send(templateFile, username, email string, data any, isDevEnv bool) (int, error) {
+	from := mail.NewEmail(FromName, s.fromEmail)
+	to := mail.NewEmail(username, email)
+
+	tmpl, err := template.ParseFS(FS, "templates/"+templateFile)
+	if err != nil {
+		return -1, err
+	}
+
+	// Template Parsing and sending
+	subject := new(bytes.Buffer)
+	if err := tmpl.ExecuteTemplate(subject, "subject", data); err != nil {
+		return -1, err
+	}
+
+	body := new(bytes.Buffer)
+	if err := tmpl.ExecuteTemplate(body, "body", data); err != nil {
+		return -1, err
+	}
+
+	message := mail.NewSingleEmail(from, subject.String(), to, "", body.String())
+
+	message.SetMailSettings(&mail.MailSettings{
+		SandboxMode: &mail.Setting{
+			Enable: &isDevEnv,
+		},
+	})
+
+	var retryErr error
+	for i := 0; i < maxRetries; i++ {
+		resp, retryErr := s.client.Send(message)
+		if retryErr != nil {
+			//* Exponential backoff
+			time.Sleep(time.Duration(i+1) * time.Second)
+			continue
+		}
+		return resp.StatusCode, nil
+	}
+	return -1, fmt.Errorf("failed to send the email after %d attempts, error: %v", maxRetries, retryErr)
+}
@@ -0,0 +1,22 @@
+{{define "subject"}} Finish Registration with {{.ServiceName}} {{end}}
+
+{{define "body"}}
+<!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 {{.Username}},</p>
+    <p>Thanks for signing up for {{.ServiceName}}. We're excited to have you on board!</p></p>
+    <p>Before you can start using {{.ServiceName}}, you need to confirm your email address. Click the link below to confirm your email address:</p>
+    <p><a href="{{.ActivationURL}}">{{.ActivationURL}}</a></p>
+    <p>If you want to activate your account manually copy and paste the code from the link above</p>
+    <p>If you didn't sign up for {{.ServiceName}}, you can safely ignore this email.</p>
+
+    <p>Thanks,</p>
+    <p>The {{.ServiceName}} Team</p>
+  </body>
+</html>
+
+{{end}}