initial public commit

tools/mailer/mailer.go

@@ -0,0 +1,18 @@
+package mailer
+
+import (
+	"io"
+	"net/mail"
+)
+
+// Mailer defines a base mail client interface.
+type Mailer interface {
+	// Send sends an email with HTML body to the specified recipient.
+	Send(
+		fromEmail mail.Address,
+		toEmail mail.Address,
+		subject string,
+		htmlBody string,
+		attachments map[string]io.Reader,
+	) error
+}

tools/mailer/sendmail.go

@@ -0,0 +1,79 @@
+package mailer
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"mime"
+	"net/http"
+	"net/mail"
+	"os/exec"
+)
+
+var _ Mailer = (*Sendmail)(nil)
+
+// Sendmail implements `mailer.Mailer` interface and defines a mail
+// client that sends emails via the `sendmail` *nix command.
+//
+// This client is usually recommended only for development and testing.
+type Sendmail struct {
+}
+
+// Send implements `mailer.Mailer` interface.
+//
+// Attachments are currently not supported.
+func (m *Sendmail) Send(
+	fromEmail mail.Address,
+	toEmail mail.Address,
+	subject string,
+	htmlBody string,
+	attachments map[string]io.Reader,
+) error {
+	headers := make(http.Header)
+	headers.Set("Subject", mime.QEncoding.Encode("utf-8", subject))
+	headers.Set("From", fromEmail.String())
+	headers.Set("To", toEmail.String())
+	headers.Set("Content-Type", "text/html; charset=UTF-8")
+
+	cmdPath, err := findSendmailPath()
+	if err != nil {
+		return err
+	}
+
+	var buffer bytes.Buffer
+
+	// write
+	// ---
+	if err := headers.Write(&buffer); err != nil {
+		return err
+	}
+	if _, err := buffer.Write([]byte("\r\n")); err != nil {
+		return err
+	}
+	if _, err := buffer.Write([]byte(htmlBody)); err != nil {
+		return err
+	}
+	// ---
+
+	sendmail := exec.Command(cmdPath, toEmail.Address)
+	sendmail.Stdin = &buffer
+
+	return sendmail.Run()
+}
+
+func findSendmailPath() (string, error) {
+	options := []string{
+		"/usr/sbin/sendmail",
+		"/usr/bin/sendmail",
+		"sendmail",
+	}
+
+	for _, option := range options {
+		path, err := exec.LookPath(option)
+		if err == nil {
+			return path, err
+		}
+	}
+
+	return "", errors.New("Failed to locate a sendmail executable path.")
+}

tools/mailer/smtp.go

@@ -0,0 +1,88 @@
+package mailer
+
+import (
+	"fmt"
+	"io"
+	"net/mail"
+	"net/smtp"
+	"regexp"
+	"strings"
+
+	"github.com/domodwyer/mailyak/v3"
+	"github.com/microcosm-cc/bluemonday"
+)
+
+var _ Mailer = (*SmtpClient)(nil)
+
+// regex to select all tabs
+var tabsRegex = regexp.MustCompile(`\t+`)
+
+// NewSmtpClient creates new `SmtpClient` with the provided configuration.
+func NewSmtpClient(
+	host string,
+	port int,
+	username string,
+	password string,
+	tls bool,
+) *SmtpClient {
+	return &SmtpClient{
+		host:     host,
+		port:     port,
+		username: username,
+		password: password,
+		tls:      tls,
+	}
+}
+
+// SmtpClient defines a SMTP mail client structure that implements
+// `mailer.Mailer` interface.
+type SmtpClient struct {
+	mail *mailyak.MailYak
+
+	host     string
+	port     int
+	username string
+	password string
+	tls      bool
+}
+
+// Send implements `mailer.Mailer` interface.
+func (m *SmtpClient) Send(
+	fromEmail mail.Address,
+	toEmail mail.Address,
+	subject string,
+	htmlBody string,
+	attachments map[string]io.Reader,
+) error {
+	smtpAuth := smtp.PlainAuth("", m.username, m.password, m.host)
+
+	// create mail instance
+	var yak *mailyak.MailYak
+	if m.tls {
+		var tlsErr error
+		yak, tlsErr = mailyak.NewWithTLS(fmt.Sprintf("%s:%d", m.host, m.port), smtpAuth, nil)
+		if tlsErr != nil {
+			return tlsErr
+		}
+	} else {
+		yak = mailyak.New(fmt.Sprintf("%s:%d", m.host, m.port), smtpAuth)
+	}
+
+	if fromEmail.Name != "" {
+		yak.FromName(fromEmail.Name)
+	}
+	yak.From(fromEmail.Address)
+	yak.To(toEmail.Address)
+	yak.Subject(subject)
+	yak.HTML().Set(htmlBody)
+
+	// set also plain text content
+	policy := bluemonday.StrictPolicy() // strips all tags
+	yak.Plain().Set(strings.TrimSpace(tabsRegex.ReplaceAllString(policy.Sanitize(htmlBody), "")))
+
+	for name, data := range attachments {
+		yak.Attach(name, data)
+	}
+
+	return yak.Send()
+}