wip: mail...

internal/common/email.go

@@ -0,0 +1,79 @@
+package common
+
+import (
+	"crypto/tls"
+	"io"
+	"net/smtp"
+	"strconv"
+	"strings"
+
+	"github.com/jordan-wright/email"
+)
+
+type MailConfig struct {
+	Host           string `yaml:"host" envconfig:"EMAIL_HOST"`
+	Port           int    `yaml:"port" envconfig:"EMAIL_PORT"`
+	TLS            bool   `yaml:"tls" envconfig:"EMAIL_TLS"`
+	CertValidation bool   `yaml:"certcheck" envconfig:"EMAIL_CERT_VALIDATION"`
+	Username       string `yaml:"user" envconfig:"EMAIL_USERNAME"`
+	Password       string `yaml:"pass" envconfig:"EMAIL_PASSWORD"`
+}
+
+type MailAttachment struct {
+	Name        string
+	ContentType string
+	Data        io.Reader
+	Embedded    bool
+}
+
+// SendEmailWithAttachments sends a mail with attachments.
+func SendEmailWithAttachments(cfg MailConfig, sender, replyTo, subject, body string, htmlBody string, receivers []string, attachments []MailAttachment) error {
+	e := email.NewEmail()
+
+	hostname := cfg.Host + ":" + strconv.Itoa(cfg.Port)
+	subject = strings.Trim(subject, "\n\r\t")
+	sender = strings.Trim(sender, "\n\r\t")
+	replyTo = strings.Trim(replyTo, "\n\r\t")
+	if replyTo == "" {
+		replyTo = sender
+	}
+
+	var auth smtp.Auth
+	if cfg.Username == "" {
+		auth = nil
+	} else {
+		// Set up authentication information.
+		auth = smtp.PlainAuth(
+			"",
+			cfg.Username,
+			cfg.Password,
+			cfg.Host,
+		)
+	}
+
+	// Set email data.
+	e.From = sender
+	e.To = receivers
+	e.ReplyTo = []string{replyTo}
+	e.Subject = subject
+	e.Text = []byte(body)
+	if htmlBody != "" {
+		e.HTML = []byte(htmlBody)
+	}
+
+	for _, attachment := range attachments {
+		a, err := e.Attach(attachment.Data, attachment.Name, attachment.ContentType)
+		if err != nil {
+			return err
+		}
+		if attachment.Embedded {
+			a.HTMLRelated = true
+		}
+	}
+
+	if cfg.CertValidation {
+		return e.Send(hostname, auth)
+	} else {
+		return e.SendWithStartTLS(hostname, auth, &tls.Config{InsecureSkipVerify: true})
+	}
+}