guinso · October 9, 2017 02:07 · lgufan · Nov 3, 2020
diff --git a/main.go b/main.go
 package main

 import (
 	"crypto/tls"
 	"encoding/base64"
 	"fmt"
 	"io/ioutil"
 	"log"
 	"net/smtp"
 	"strings"
 )

 //https://hackernoon.com/golang-sendmail-sending-mail-through-net-smtp-package-5cadbe2670e0
 //https://msdn.microsoft.com/en-us/library/ms526560(v=exchg.10).aspx
 func main() {
 	var (
 		serverAddr = "smtp.gmail.com"
 		password   = "your-email-password"
 		emailAddr  = "[email protected]"
 		portNumber = 465
 		tos        = []string{
 			"[email protected]",
 			"[email protected]",
 		}
 		cc = []string{
 			"[email protected]",
 		}
 		attachmentFilePath = "/your/attachment-filepath"
 		filename           = "logFileUI.txt"
 		delimeter          = "**=myohmy689407924327"
 	)

 	log.Println("======= Test Gmail client (with attachment) =========")
 	log.Println("NOTE: user need to turn on 'less secure apps' options")
 	log.Println("URL:  https://myaccount.google.com/lesssecureapps\n\r")

 	tlsConfig := tls.Config{
 		ServerName:         serverAddr,
 		InsecureSkipVerify: true,
 	}

 	log.Println("Establish TLS connection")
 	conn, connErr := tls.Dial("tcp", fmt.Sprintf("%s:%d", serverAddr, portNumber), &tlsConfig)
 	if connErr != nil {
 		log.Panic(connErr)
 	}
 	defer conn.Close()

 	log.Println("create new email client")
 	client, clientErr := smtp.NewClient(conn, serverAddr)
 	if clientErr != nil {
 		log.Panic(clientErr)
 	}
 	defer client.Close()

 	log.Println("setup authenticate credential")
 	auth := smtp.PlainAuth("", emailAddr, password, serverAddr)

 	if err := client.Auth(auth); err != nil {
 		log.Panic(err)
 	}

 	log.Println("Start write mail content")
 	log.Println("Set 'FROM'")
 	if err := client.Mail(emailAddr); err != nil {
 		log.Panic(err)
 	}
 	log.Println("Set 'TO(s)'")
 	for _, to := range tos {
 		if err := client.Rcpt(to); err != nil {
 			log.Panic(err)
 		}
 	}

 	writer, writerErr := client.Data()
 	if writerErr != nil {
 		log.Panic(writerErr)
 	}

 	//basic email headers
 	sampleMsg := fmt.Sprintf("From: %s\r\n", emailAddr)
 	sampleMsg += fmt.Sprintf("To: %s\r\n", strings.Join(tos, ";"))
 	if len(cc) > 0 {
 		sampleMsg += fmt.Sprintf("Cc: %s\r\n", strings.Join(cc, ";"))
 	}
 	sampleMsg += "Subject: Golang example send mail in HTML format with attachment\r\n"

 	log.Println("Mark content to accept multiple contents")
 	sampleMsg += "MIME-Version: 1.0\r\n"
 	sampleMsg += fmt.Sprintf("Content-Type: multipart/mixed; boundary=\"%s\"\r\n", delimeter)

 	//place HTML message
 	log.Println("Put HTML message")
 	sampleMsg += fmt.Sprintf("\r\n--%s\r\n", delimeter)
 	sampleMsg += "Content-Type: text/html; charset=\"utf-8\"\r\n"
 	sampleMsg += "Content-Transfer-Encoding: 7bit\r\n"
 	sampleMsg += fmt.Sprintf("\r\n%s", "<html><body><h1>Hi There</h1>"+
 		"<p>this is sample email (with attachment) sent via golang program</p></body></html>\r\n")

 	//place file
 	log.Println("Put file attachment")
 	sampleMsg += fmt.Sprintf("\r\n--%s\r\n", delimeter)
 	sampleMsg += "Content-Type: text/plain; charset=\"utf-8\"\r\n"
 	sampleMsg += "Content-Transfer-Encoding: base64\r\n"
 	sampleMsg += "Content-Disposition: attachment;filename=\"" + filename + "\"\r\n"
 	//read file
 	rawFile, fileErr := ioutil.ReadFile(attachmentFilePath)
 	if fileErr != nil {
 		log.Panic(fileErr)
 	}
 	sampleMsg += "\r\n" + base64.StdEncoding.EncodeToString(rawFile)

 	//write into email client stream writter
 	log.Println("Write content into client writter I/O")
 	if _, err := writer.Write([]byte(sampleMsg)); err != nil {
 		log.Panic(err)
 	}

 	if closeErr := writer.Close(); closeErr != nil {
 		log.Panic(closeErr)
 	}

 	client.Quit()

 	log.Print("done.")
 }
	package main

	import (
	"crypto/tls"
	"encoding/base64"
	"fmt"
	"io/ioutil"
	"log"
	"net/smtp"
	"strings"
	)

	//https://hackernoon.com/golang-sendmail-sending-mail-through-net-smtp-package-5cadbe2670e0
	//https://msdn.microsoft.com/en-us/library/ms526560(v=exchg.10).aspx
	func main() {
	var (
	serverAddr = "smtp.gmail.com"
	password = "your-email-password"
	emailAddr = "[email protected]"
	portNumber = 465
	tos = []string{
	"[email protected]",
	"[email protected]",
	}
	cc = []string{
	"[email protected]",
	}
	attachmentFilePath = "/your/attachment-filepath"
	filename = "logFileUI.txt"
	delimeter = "**=myohmy689407924327"
	)

	log.Println("======= Test Gmail client (with attachment) =========")
	log.Println("NOTE: user need to turn on 'less secure apps' options")
	log.Println("URL: https://myaccount.google.com/lesssecureapps\n\r")

	tlsConfig := tls.Config{
	ServerName: serverAddr,
	InsecureSkipVerify: true,
	}

	log.Println("Establish TLS connection")
	conn, connErr := tls.Dial("tcp", fmt.Sprintf("%s:%d", serverAddr, portNumber), &tlsConfig)
	if connErr != nil {
	log.Panic(connErr)
	}
	defer conn.Close()

	log.Println("create new email client")
	client, clientErr := smtp.NewClient(conn, serverAddr)
	if clientErr != nil {
	log.Panic(clientErr)
	}
	defer client.Close()

	log.Println("setup authenticate credential")
	auth := smtp.PlainAuth("", emailAddr, password, serverAddr)

	if err := client.Auth(auth); err != nil {
	log.Panic(err)
	}

	log.Println("Start write mail content")
	log.Println("Set 'FROM'")
	if err := client.Mail(emailAddr); err != nil {
	log.Panic(err)
	}
	log.Println("Set 'TO(s)'")
	for _, to := range tos {
	if err := client.Rcpt(to); err != nil {
	log.Panic(err)
	}
	}

	writer, writerErr := client.Data()
	if writerErr != nil {
	log.Panic(writerErr)
	}

	//basic email headers
	sampleMsg := fmt.Sprintf("From: %s\r\n", emailAddr)
	sampleMsg += fmt.Sprintf("To: %s\r\n", strings.Join(tos, ";"))
	if len(cc) > 0 {
	sampleMsg += fmt.Sprintf("Cc: %s\r\n", strings.Join(cc, ";"))
	}
	sampleMsg += "Subject: Golang example send mail in HTML format with attachment\r\n"

	log.Println("Mark content to accept multiple contents")
	sampleMsg += "MIME-Version: 1.0\r\n"
	sampleMsg += fmt.Sprintf("Content-Type: multipart/mixed; boundary=\"%s\"\r\n", delimeter)

	//place HTML message
	log.Println("Put HTML message")
	sampleMsg += fmt.Sprintf("\r\n--%s\r\n", delimeter)
	sampleMsg += "Content-Type: text/html; charset=\"utf-8\"\r\n"
	sampleMsg += "Content-Transfer-Encoding: 7bit\r\n"
	sampleMsg += fmt.Sprintf("\r\n%s", "<html><body><h1>Hi There</h1>"+
	"<p>this is sample email (with attachment) sent via golang program</p></body></html>\r\n")

	//place file
	log.Println("Put file attachment")
	sampleMsg += fmt.Sprintf("\r\n--%s\r\n", delimeter)
	sampleMsg += "Content-Type: text/plain; charset=\"utf-8\"\r\n"
	sampleMsg += "Content-Transfer-Encoding: base64\r\n"
	sampleMsg += "Content-Disposition: attachment;filename=\"" + filename + "\"\r\n"
	//read file
	rawFile, fileErr := ioutil.ReadFile(attachmentFilePath)
	if fileErr != nil {
	log.Panic(fileErr)
	}
	sampleMsg += "\r\n" + base64.StdEncoding.EncodeToString(rawFile)

	//write into email client stream writter
	log.Println("Write content into client writter I/O")
	if _, err := writer.Write([]byte(sampleMsg)); err != nil {
	log.Panic(err)
	}

	if closeErr := writer.Close(); closeErr != nil {
	log.Panic(closeErr)
	}

	client.Quit()

	log.Print("done.")
	}