initial commit

email/email.go

@@ -0,0 +1,148 @@
+package email
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/jaytaylor/html2text"
+	"github.com/spf13/viper"
+	"github.com/vanng822/go-premailer/premailer"
+	"gopkg.in/gomail.v2"
+)
+
+var (
+	debug bool
+)
+
+type EmailService struct {
+	client         *gomail.Dialer
+	templates      *template.Template
+	from, fromName string
+}
+
+func NewEmailService() (*EmailService, error) {
+	templates, err := parseTemplates()
+	if err != nil {
+		return nil, err
+	}
+
+	smtpHost := viper.GetString("email_smtp_host")
+	smtpPort := viper.GetInt("email_smtp_port")
+	smtpUser := viper.GetString("email_smtp_user")
+	smtpPass := viper.GetString("email_smtp_password")
+
+	s := &EmailService{
+		client:    gomail.NewPlainDialer(smtpHost, smtpPort, smtpUser, smtpPass),
+		templates: templates,
+		from:      viper.GetString("email_from_address"),
+		fromName:  viper.GetString("email_from_name"),
+	}
+
+	d, err := s.client.Dial()
+	if err != nil {
+		log.Println("SMTP error:", err)
+		log.Println("printing emails to stdout")
+		debug = true
+	} else {
+		d.Close()
+	}
+	return s, nil
+}
+
+func (s *EmailService) send(msg *Message) error {
+	buf := new(bytes.Buffer)
+	if err := s.templates.ExecuteTemplate(buf, msg.template, msg.content); err != nil {
+		return err
+	}
+	prem := premailer.NewPremailerFromString(buf.String(), premailer.NewOptions())
+	html, err := prem.Transform()
+	if err != nil {
+		return err
+	}
+
+	text, err := html2text.FromString(html, html2text.Options{PrettyTables: true})
+	if err != nil {
+		return err
+	}
+
+	if debug {
+		log.Println("To:", msg.to.Address)
+		log.Println("Subject:", msg.subject)
+		log.Println(text)
+		return nil
+	}
+
+	m := gomail.NewMessage()
+	m.SetAddressHeader("From", msg.from.Address, msg.from.Name)
+	m.SetAddressHeader("To", msg.to.Address, msg.to.Name)
+	m.SetHeader("Subject", msg.subject)
+	m.SetBody("text/plain", text)
+	m.AddAlternative("text/html", html)
+
+	if err := s.client.DialAndSend(m); err != nil {
+		return err
+	}
+	return nil
+}
+
+type Email struct {
+	Name    string
+	Address string
+}
+
+func NewEmail(name string, address string) *Email {
+	return &Email{
+		Name:    name,
+		Address: address,
+	}
+}
+
+type Message struct {
+	from     *Email
+	to       *Email
+	subject  string
+	template string
+	content  interface{}
+}
+
+func parseTemplates() (*template.Template, error) {
+	tmpl := template.New("").Funcs(fMap)
+	err := filepath.Walk("./templates", func(path string, info os.FileInfo, err error) error {
+		if strings.Contains(path, ".html") {
+			_, err = tmpl.ParseFiles(path)
+			return err
+		}
+		return err
+	})
+	return tmpl, err
+}
+
+var fMap = template.FuncMap{
+	"formatAsDate":     formatAsDate,
+	"formatAsDuration": formatAsDuration,
+}
+
+func formatAsDate(t time.Time) string {
+	year, month, day := t.Date()
+	return fmt.Sprintf("%d.%d.%d", day, month, year)
+}
+
+func formatAsDuration(t time.Time) string {
+	dur := t.Sub(time.Now())
+	hours := int(dur.Hours())
+	mins := int(dur.Minutes())
+
+	v := ""
+	if hours != 0 {
+		v += strconv.Itoa(hours) + " hours and "
+	}
+	v += strconv.Itoa(mins) + " minutes"
+	return v
+}