prototype-pattern-ใน-go-5e9088fc0e16fb18c1d56c13

main.go

package main

import (
	"net/smtp"
	"strings"
)

func main() {
	s := NewNoAuthSender("localhost:25")
	err := s.From("[email protected]").
		To([]string{"admin@localhost"}).
		Subject("HTML<ipsum> is awesome!").
		HTML(`<h1>HTML Ipsum Presents</h1>

<p><strong>Pellentesque habitant morbi tristique</strong> senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. <em>Aenean ultricies mi vitae est.</em> Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, <code>commodo vitae</code>, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui. <a href="#">Donec non enim</a> in turpis pulvinar facilisis. Ut felis.</p>

<h2>Header Level 2</h2>

<ol>
   <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
   <li>Aliquam tincidunt mauris eu risus.</li>
</ol>

<blockquote><p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est.</p></blockquote>

<h3>Header Level 3</h3>

<ul>
   <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
   <li>Aliquam tincidunt mauris eu risus.</li>
</ul>

<pre><code>
#header h1 a {
  display: block;
  width: 300px;
  height: 80px;
}
</code></pre>`).
		Send()
	if err != nil {
		panic(err)
	}
}

// Sender is a Prototype Pattern supported interface for sending email
type Sender interface {
	From(addr string) Sender
	To(rcpt []string) Sender
	Subject(subj string) Sender
	Text(content string) Sender
	HTML(content string) Sender
	Send() error
}

// NoAuthSender is an SMTP client that isn't support the authentication
type NoAuthSender struct {
	addr    string
	from    string
	to      []string
	subject string
	content string
	mime    string
}

// NewNoAuthSender returns a new NoAuthSender instance
func NewNoAuthSender(addr string) NoAuthSender {
	return NoAuthSender{addr: addr}
}

// From sets from email address
func (a NoAuthSender) From(addr string) Sender {
	a.from = addr
	return a
}

// To sets one or more recipient addresses
func (a NoAuthSender) To(rcpt []string) Sender {
	a.to = rcpt
	return a
}

// Subject sets subject
func (a NoAuthSender) Subject(subj string) Sender {
	a.subject = subj
	return a
}

// Text sets its content in plain text message
func (a NoAuthSender) Text(content string) Sender {
	a.mime = strings.Join([]string{
		"MIME-version: 1.0;",
		`Content-Type: text/plain; charset="UTF-8";`,
		"",
	}, "\n")
	a.content = content
	return a
}

// HTML sets its content in HTML message
func (a NoAuthSender) HTML(content string) Sender {
	a.mime = strings.Join([]string{
		"MIME-version: 1.0;",
		`Content-Type: text/html; charset="UTF-8";`,
		"",
	}, "\n")
	a.content = content
	return a
}

// Send executes smtp.SendMail function for sending an email message
func (a NoAuthSender) Send() error {
	msg := strings.Join([]string{
		"Subject: " + a.subject,
		a.mime,
		a.content,
	}, "\n")
	return smtp.SendMail(a.addr, nil, a.from, a.to, []byte(msg))
}

noauth_sender.go

// NoAuthSender is an SMTP client that isn't support the authentication
type NoAuthSender struct {
	addr    string
	from    string
	to      []string
	subject string
	content string
	mime    string
}

// NewNoAuthSender returns a new NoAuthSender instance
func NewNoAuthSender(addr string) NoAuthSender {
	return NoAuthSender{addr: addr}
}

// From sets from email address
func (a NoAuthSender) From(addr string) Sender {
	a.from = addr
	return a
}

// To sets one or more recipient addresses
func (a NoAuthSender) To(rcpt []string) Sender {
	a.to = rcpt
	return a
}

// Subject sets subject
func (a NoAuthSender) Subject(subj string) Sender {
	a.subject = subj
	return a
}

// Text sets its content in plain text message
func (a NoAuthSender) Text(content string) Sender {
	a.mime = strings.Join([]string{
		"MIME-version: 1.0;",
		`Content-Type: text/plain; charset="UTF-8";`,
		"",
	}, "\n")
	a.content = content
	return a
}

// HTML sets its content in HTML message
func (a NoAuthSender) HTML(content string) Sender {
	a.mime = strings.Join([]string{
		"MIME-version: 1.0;",
		`Content-Type: text/html; charset="UTF-8";`,
		"",
	}, "\n")
	a.content = content
	return a
}

// Send executes smtp.SendMail function for sending an email message
func (a NoAuthSender) Send() error {
	msg := strings.Join([]string{
		"Subject: " + a.subject,
		a.mime,
		a.content,
	}, "\n")
	return smtp.SendMail(a.addr, nil, a.from, a.to, []byte(msg))
}

sender.go

// Sender is a Prototype Pattern supported interface for sending email
type Sender interface {
	From(addr string) Sender
	To(rcpt []string) Sender
	Subject(subj string) Sender
	Text(content string) Sender
	HTML(content string) Sender
	Send() error
}