gomail

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Published: Dec 21, 2015 License: MIT, Apache-2.0 Imports: 15 Imported by: 0

README

Gomail

Build Status Code Coverage Documentation

Introduction

Gomail is a simple and efficient package to send emails. It is well tested and documented.

Gomail can only send emails using an SMTP server. But the API is flexible and it is easy to implement other methods for sending emails using a local Postfix, an API, etc.

It is versioned using gopkg.in so I promise they will never be backward incompatible changes within each version.

It requires Go 1.2 or newer. With Go 1.5, no external dependencies are used.

Features

Gomail supports:

  • Attachments
  • Embedded images
  • HTML and text templates
  • Automatic encoding of special characters
  • SSL and TLS
  • Sending multiple emails with the same SMTP connection

Documentation

https://godoc.org/gopkg.in/gomail.v2

Download

go get gopkg.in/gomail.v2

Examples

See the examples in the documentation.

FAQ

x509: certificate signed by unknown authority

If you get this error it means the certificate used by the SMTP server is not considered valid by the client running Gomail. As a quick workaround you can bypass the verification of the server's certificate chain and host name by using SetTLSConfig:

d := gomail.NewPlainDialer("smtp.example.com", "user", "123456", 587)
d.TLSConfig = &tls.Config{InsecureSkipVerify: true}

Note, however, that this is insecure and should not be used in production.

Contribute

Contributions are more than welcome! See CONTRIBUTING.md for more info.

Change log

See CHANGELOG.md.

License

MIT

Contact

You can ask questions on the Gomail thread in the Go mailing-list.

Support

If you want to support the development of Gomail, I gladly accept donations.

I will give 100% of the money I receive to Enfants, Espoir Du Monde. EEDM is a French NGO which helps children in Bangladesh, Cameroun, Haiti, India and Madagascar.

All its members are volunteers so its operating costs are only 1.9%. So your money will directly help children of these countries.

As an added bonus, your donations will also tip me by lowering my taxes 😄

I will send an email with the receipt of the donation to EEDM annually to all donors.

Donate

Documentation

Overview

Package gomail provides a simple interface to compose emails and to mail them efficiently.

More info on Github: https://github.com/go-gomail/gomail

Example
m := gomail.NewMessage()
m.SetHeader("From", "alex@example.com")
m.SetHeader("To", "bob@example.com", "cora@example.com")
m.SetAddressHeader("Cc", "dan@example.com", "Dan")
m.SetHeader("Subject", "Hello!")
m.SetBody("text/html", "Hello <b>Bob</b> and <i>Cora</i>!")
m.Attach("/home/Alex/lolcat.jpg")

d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")

// Send the email to Bob, Cora and Dan.
if err := d.DialAndSend(m); err != nil {
	panic(err)
}
Output:

Example (Daemon)

A daemon that listens to a channel and sends all incoming messages.

ch := make(chan *gomail.Message)

go func() {
	d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")

	var s gomail.SendCloser
	var err error
	open := false
	for {
		select {
		case m, ok := <-ch:
			if !ok {
				return
			}
			if !open {
				if s, err = d.Dial(); err != nil {
					panic(err)
				}
				open = true
			}
			if err := gomail.Send(s, m); err != nil {
				log.Print(err)
			}
		// Close the connection to the SMTP server if no email was sent in
		// the last 30 seconds.
		case <-time.After(30 * time.Second):
			if open {
				if err := s.Close(); err != nil {
					panic(err)
				}
				open = false
			}
		}
	}
}()

// Use the channel in your program to send emails.

// Close the channel to stop the mail daemon.
close(ch)
Output:

Example (Newsletter)

Efficiently send a customized newsletter to a list of recipients.

// The list of recipients.
var list []struct {
	Name    string
	Address string
}

d := gomail.NewPlainDialer("smtp.example.com", 587, "user", "123456")
s, err := d.Dial()
if err != nil {
	panic(err)
}

m := gomail.NewMessage()
for _, r := range list {
	m.SetHeader("From", "no-reply@example.com")
	m.SetAddressHeader("To", r.Address, r.Name)
	m.SetHeader("Subject", "Newsletter #1")
	m.SetBody("text/html", fmt.Sprintf("Hello %s!", r.Name))

	if err := gomail.Send(s, m); err != nil {
		log.Printf("Could not send email to %q: %v", r.Address, err)
	}
	m.Reset()
}
Output:

Example (NoAuth)

Send an email using a local SMTP server.

m := gomail.NewMessage()
m.SetHeader("From", "from@example.com")
m.SetHeader("To", "to@example.com")
m.SetHeader("Subject", "Hello!")
m.SetBody("text/plain", "Hello!")

d := gomail.Dialer{Host: "localhost", Port: 587}
if err := d.DialAndSend(m); err != nil {
	panic(err)
}
Output:

Example (NoSMTP)

Send an email using an API or postfix.

m := gomail.NewMessage()
m.SetHeader("From", "from@example.com")
m.SetHeader("To", "to@example.com")
m.SetHeader("Subject", "Hello!")
m.SetBody("text/plain", "Hello!")

s := gomail.SendFunc(func(from string, to []string, msg io.WriterTo) error {
	// Implements you email-sending function, for example by calling
	// an API, or running postfix, etc.
	fmt.Println("From:", from)
	fmt.Println("To:", to)
	return nil
})

if err := gomail.Send(s, m); err != nil {
	panic(err)
}
Output:

From: from@example.com
To: [to@example.com]

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func Send

func Send(s Sender, msg ...*Message) error

Send sends emails using the given Sender.

Types

type Dialer

type Dialer struct {
	// Host represents the host of the SMTP server.
	Host string
	// Port represents the port of the SMTP server.
	Port int
	// Auth represents the authentication mechanism used to authenticate to the
	// SMTP server.
	Auth smtp.Auth
	// SSL defines whether an SSL connection is used. It should be false in
	// most cases since the authentication mechanism should use the STARTTLS
	// extension instead.
	SSL bool
	// TSLConfig represents the TLS configuration used for the TLS (when the
	// STARTTLS extension is used) or SSL connection.
	TLSConfig *tls.Config
}

A Dialer is a dialer to an SMTP server.

func NewPlainDialer

func NewPlainDialer(host string, port int, username, password string) *Dialer

NewPlainDialer returns a Dialer. The given parameters are used to connect to the SMTP server via a PLAIN authentication mechanism.

It fallbacks to the LOGIN mechanism if it is the only mechanism advertised by the server.

func (*Dialer) Dial

func (d *Dialer) Dial() (SendCloser, error)

Dial dials and authenticates to an SMTP server. The returned SendCloser should be closed when done using it.

func (*Dialer) DialAndSend

func (d *Dialer) DialAndSend(m ...*Message) error

DialAndSend opens a connection to the SMTP server, sends the given emails and closes the connection.

type Encoding

type Encoding string

Encoding represents a MIME encoding scheme like quoted-printable or base64.

const (
	// QuotedPrintable represents the quoted-printable encoding as defined in
	// RFC 2045.
	QuotedPrintable Encoding = "quoted-printable"
	// Base64 represents the base64 encoding as defined in RFC 2045.
	Base64 Encoding = "base64"
	// Unencoded can be used to avoid encoding the body of an email. The headers
	// will still be encoded using quoted-printable encoding.
	Unencoded Encoding = "8bit"
)

type FileSetting

type FileSetting func(*file)

A FileSetting can be used as an argument in Message.Attach or Message.Embed.

func SetCopyFunc

func SetCopyFunc(f func(io.Writer) error) FileSetting

SetCopyFunc is a file setting to replace the function that runs when the message is sent. It should copy the content of the file to the io.Writer.

The default copy function opens the file with the given filename, and copy its content to the io.Writer.

Example
m.Attach("foo.txt", gomail.SetCopyFunc(func(w io.Writer) error {
	_, err := w.Write([]byte("Content of foo.txt"))
	return err
}))
Output:

func SetHeader

func SetHeader(h map[string][]string) FileSetting

SetHeader is a file setting to set the MIME header of the message part that contains the file content.

Mandatory headers are automatically added if they are not set when sending the email.

Example
h := map[string][]string{"Content-ID": {"<foo@bar.mail>"}}
m.Attach("foo.jpg", gomail.SetHeader(h))
Output:

type Message

type Message struct {
	// contains filtered or unexported fields
}

Message represents an email.

func NewMessage

func NewMessage(settings ...MessageSetting) *Message

NewMessage creates a new message. It uses UTF-8 and quoted-printable encoding by default.

func (*Message) AddAlternative

func (m *Message) AddAlternative(contentType, body string)

AddAlternative adds an alternative part to the message.

It is commonly used to send HTML emails that default to the plain text version for backward compatibility.

More info: http://en.wikipedia.org/wiki/MIME#Alternative

Example
m.SetBody("text/plain", "Hello!")
m.AddAlternative("text/html", "<p>Hello!</p>")
Output:

func (*Message) AddAlternativeWriter

func (m *Message) AddAlternativeWriter(contentType string, f func(io.Writer) error)

AddAlternativeWriter adds an alternative part to the message. It can be useful with the text/template or html/template packages.

Example
t := template.Must(template.New("example").Parse("Hello {{.}}!"))
m.AddAlternativeWriter("text/plain", func(w io.Writer) error {
	return t.Execute(w, "Bob")
})
Output:

func (*Message) Attach

func (m *Message) Attach(filename string, settings ...FileSetting)

Attach attaches the files to the email.

Example
m.Attach("/tmp/image.jpg")
Output:

func (*Message) Embed

func (m *Message) Embed(filename string, settings ...FileSetting)

Embed embeds the images to the email.

Example
m.Embed("/tmp/image.jpg")
m.SetBody("text/html", `<img src="cid:image.jpg" alt="My image" />`)
Output:

func (*Message) FormatAddress

func (m *Message) FormatAddress(address, name string) string

FormatAddress formats an address and a name as a valid RFC 5322 address.

Example
m.SetHeader("To", m.FormatAddress("bob@example.com", "Bob"), m.FormatAddress("cora@example.com", "Cora"))
Output:

func (*Message) FormatDate

func (m *Message) FormatDate(date time.Time) string

FormatDate formats a date as a valid RFC 5322 date.

Example
m.SetHeaders(map[string][]string{
	"X-Date": {m.FormatDate(time.Now())},
})
Output:

func (*Message) GetHeader

func (m *Message) GetHeader(field string) []string

GetHeader gets a header field.

func (*Message) Reset

func (m *Message) Reset()

Reset resets the message so it can be reused. The message keeps its previous settings so it is in the same state that after a call to NewMessage.

func (*Message) SetAddressHeader

func (m *Message) SetAddressHeader(field, address, name string)

SetAddressHeader sets an address to the given header field.

Example
m.SetAddressHeader("To", "bob@example.com", "Bob")
Output:

func (*Message) SetBody

func (m *Message) SetBody(contentType, body string)

SetBody sets the body of the message.

Example
m.SetBody("text/plain", "Hello!")
Output:

func (*Message) SetDateHeader

func (m *Message) SetDateHeader(field string, date time.Time)

SetDateHeader sets a date to the given header field.

Example
m.SetDateHeader("X-Date", time.Now())
Output:

func (*Message) SetHeader

func (m *Message) SetHeader(field string, value ...string)

SetHeader sets a value to the given header field.

Example
m.SetHeader("Subject", "Hello!")
Output:

func (*Message) SetHeaders

func (m *Message) SetHeaders(h map[string][]string)

SetHeaders sets the message headers.

Example
m.SetHeaders(map[string][]string{
	"From":    {m.FormatAddress("alex@example.com", "Alex")},
	"To":      {"bob@example.com", "cora@example.com"},
	"Subject": {"Hello"},
})
Output:

func (*Message) WriteTo

func (m *Message) WriteTo(w io.Writer) (int64, error)

WriteTo implements io.WriterTo. It dumps the whole message into w.

type MessageSetting

type MessageSetting func(m *Message)

A MessageSetting can be used as an argument in NewMessage to configure an email.

func SetCharset

func SetCharset(charset string) MessageSetting

SetCharset is a message setting to set the charset of the email.

Example
m = gomail.NewMessage(gomail.SetCharset("ISO-8859-1"))
Output:

func SetEncoding

func SetEncoding(enc Encoding) MessageSetting

SetEncoding is a message setting to set the encoding of the email.

Example
m = gomail.NewMessage(gomail.SetEncoding(gomail.Base64))
Output:

type SendCloser

type SendCloser interface {
	Sender
	Close() error
}

SendCloser is the interface that groups the Send and Close methods.

type SendFunc

type SendFunc func(from string, to []string, msg io.WriterTo) error

A SendFunc is a function that sends emails to the given adresses.

The SendFunc type is an adapter to allow the use of ordinary functions as email senders. If f is a function with the appropriate signature, SendFunc(f) is a Sender object that calls f.

func (SendFunc) Send

func (f SendFunc) Send(from string, to []string, msg io.WriterTo) error

Send calls f(from, to, msg).

type Sender

type Sender interface {
	Send(from string, to []string, msg io.WriterTo) error
}

Sender is the interface that wraps the Send method.

Send sends an email to the given addresses.

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