initial version

email.go

@@ -0,0 +1,191 @@
+// Package email allows to send emails with attachments.
+package email
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"mime"
+	"net/mail"
+	"net/smtp"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// Attachment represents an email attachment.
+type Attachment struct {
+	Filename string
+	Data     []byte
+	Inline   bool
+}
+
+// Message represents a smtp message.
+type Message struct {
+	From            mail.Address
+	To              []string
+	Cc              []string
+	Bcc             []string
+	ReplyTo         string
+	Subject         string
+	Body            string
+	BodyContentType string
+	Attachments     map[string]*Attachment
+}
+
+func (m *Message) attach(file string, inline bool) error {
+	data, err := ioutil.ReadFile(file)
+	if err != nil {
+		return err
+	}
+
+	_, filename := filepath.Split(file)
+
+	m.Attachments[filename] = &Attachment{
+		Filename: filename,
+		Data:     data,
+		Inline:   inline,
+	}
+
+	return nil
+}
+
+// AttachBuffer attaches a binary attachment.
+func (m *Message) AttachBuffer(filename string, buf []byte, inline bool) error {
+	m.Attachments[filename] = &Attachment{
+		Filename: filename,
+		Data:     buf,
+		Inline:   inline,
+	}
+	return nil
+}
+
+// Attach attaches a file.
+func (m *Message) Attach(file string) error {
+	return m.attach(file, false)
+}
+
+// Inline includes a file as an inline attachment.
+func (m *Message) Inline(file string) error {
+	return m.attach(file, true)
+}
+
+func newMessage(subject string, body string, bodyContentType string) *Message {
+	m := &Message{Subject: subject, Body: body, BodyContentType: bodyContentType}
+
+	m.Attachments = make(map[string]*Attachment)
+
+	return m
+}
+
+// NewMessage returns a new Message that can compose an email with attachments
+func NewMessage(subject string, body string) *Message {
+	return newMessage(subject, body, "text/plain")
+}
+
+// NewHTMLMessage returns a new Message that can compose an HTML email with attachments
+func NewHTMLMessage(subject string, body string) *Message {
+	return newMessage(subject, body, "text/html")
+}
+
+// Tolist returns all the recipients of the email
+func (m *Message) Tolist() []string {
+	tolist := m.To
+
+	for _, cc := range m.Cc {
+		tolist = append(tolist, cc)
+	}
+
+	for _, bcc := range m.Bcc {
+		tolist = append(tolist, bcc)
+	}
+
+	return tolist
+}
+
+// Bytes returns the mail data
+func (m *Message) Bytes() []byte {
+	buf := bytes.NewBuffer(nil)
+
+	buf.WriteString("From: " + m.From.String() + "\r\n")
+
+	t := time.Now()
+	buf.WriteString("Date: " + t.Format(time.RFC1123Z) + "\r\n")
+
+	buf.WriteString("To: " + strings.Join(m.To, ",") + "\r\n")
+	if len(m.Cc) > 0 {
+		buf.WriteString("Cc: " + strings.Join(m.Cc, ",") + "\r\n")
+	}
+
+	//fix  Encode
+	var coder = base64.StdEncoding
+	var subject = "=?UTF-8?B?" + coder.EncodeToString([]byte(m.Subject)) + "?="
+	buf.WriteString("Subject: " + subject + "\r\n")
+
+	if len(m.ReplyTo) > 0 {
+		buf.WriteString("Reply-To: " + m.ReplyTo + "\r\n")
+	}
+
+	buf.WriteString("MIME-Version: 1.0\r\n")
+
+	boundary := "f46d043c813270fc6b04c2d223da"
+
+	if len(m.Attachments) > 0 {
+		buf.WriteString("Content-Type: multipart/mixed; boundary=" + boundary + "\r\n")
+		buf.WriteString("\r\n--" + boundary + "\r\n")
+	}
+
+	buf.WriteString(fmt.Sprintf("Content-Type: %s; charset=utf-8\r\n\r\n", m.BodyContentType))
+	buf.WriteString(m.Body)
+	buf.WriteString("\r\n")
+
+	if len(m.Attachments) > 0 {
+		for _, attachment := range m.Attachments {
+			buf.WriteString("\r\n\r\n--" + boundary + "\r\n")
+
+			if attachment.Inline {
+				buf.WriteString("Content-Type: message/rfc822\r\n")
+				buf.WriteString("Content-Disposition: inline; filename=\"" + attachment.Filename + "\"\r\n\r\n")
+
+				buf.Write(attachment.Data)
+			} else {
+				ext := filepath.Ext(attachment.Filename)
+				mimetype := mime.TypeByExtension(ext)
+				if mimetype != "" {
+					mime := fmt.Sprintf("Content-Type: %s\r\n", mimetype)
+					buf.WriteString(mime)
+				} else {
+					buf.WriteString("Content-Type: application/octet-stream\r\n")
+				}
+				buf.WriteString("Content-Transfer-Encoding: base64\r\n")
+
+				buf.WriteString("Content-Disposition: attachment; filename=\"=?UTF-8?B?")
+				buf.WriteString(coder.EncodeToString([]byte(attachment.Filename)))
+				buf.WriteString("?=\"\r\n\r\n")
+
+				b := make([]byte, base64.StdEncoding.EncodedLen(len(attachment.Data)))
+				base64.StdEncoding.Encode(b, attachment.Data)
+
+				// write base64 content in lines of up to 76 chars
+				for i, l := 0, len(b); i < l; i++ {
+					buf.WriteByte(b[i])
+					if (i+1)%76 == 0 {
+						buf.WriteString("\r\n")
+					}
+				}
+			}
+
+			buf.WriteString("\r\n--" + boundary)
+		}
+
+		buf.WriteString("--")
+	}
+
+	return buf.Bytes()
+}
+
+// Send sends the message.
+func Send(addr string, auth smtp.Auth, m *Message) error {
+	return smtp.SendMail(addr, auth, m.From.Address, m.Tolist(), m.Bytes())
+}

email_test.go

@@ -0,0 +1,18 @@
+package email
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestAttachment(t *testing.T) {
+	m := NewMessage("Hi", "this is the body")
+
+	if err := m.AttachBuffer("test.ics", []byte("test"), false); err != nil {
+		t.Fatal(err)
+	}
+
+	if strings.Contains(string(m.Bytes()), "text/calendar") == false {
+		t.Fatal("Issue with mailer")
+	}
+}

example/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"log"
+	"net/mail"
+	"net/smtp"
+	"strconv"
+	"qoobing.com/gomod/email"
+)
+
+func main() {
+	fromAddr := "ubbeybox@yqtc.com"
+	fromPass := "yqtc@018ubox"
+	fromSmtpAddr := "smtp.gmail.com"
+	fromSmtpPort := 587 //465;//587
+	toAddr := "q.bryant@live.com"
+	// compose the message
+	m := email.NewMessage("Hi", "this is the body")
+	m.From = mail.Address{Name: "From", Address: fromAddr}
+	m.To = []string{toAddr}
+
+	// add attachments
+	if err := m.Attach("email.go"); err != nil {
+		log.Fatal(err)
+	}
+
+	// send it
+	auth := smtp.PlainAuth("", fromAddr, fromPass, fromSmtpAddr)
+	if err := email.Send(fromSmtpAddr+":"+strconv.Itoa(fromSmtpPort), auth, m); err != nil {
+		log.Fatal(err)
+	} else {
+		log.Println("done")
+	}
+}

go.mod

@@ -0,0 +1,3 @@
+module qoobing.com/gomod/email
+
+go 1.14