Package mail

m := mail.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 := mail.NewDialer("smtp.example.com", 587, "user", "123456")
d.StartTLSPolicy = mail.MandatoryStartTLS

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

ch := make(chan *mail.Message)

go func() {
    d := mail.NewDialer("smtp.example.com", 587, "user", "123456")
    d.StartTLSPolicy = mail.MandatoryStartTLS

    var s mail.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 := mail.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)

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

d := mail.NewDialer("smtp.example.com", 587, "user", "123456")
d.StartTLSPolicy = mail.MandatoryStartTLS
s, err := d.Dial()
if err != nil {
    panic(err)
}

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

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

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

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

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

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

Variables

NetDialTimeout specifies the DialTimeout function to establish a connection to the SMTP server. This can be used to override dialing in the case that a proxy or other special behavior is needed.

var NetDialTimeout = net.DialTimeout

func Send ¶

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

Send sends emails using the given Sender.

type Dialer ¶

A Dialer is a dialer to an SMTP server.

type Dialer struct {
    // Host represents the host of the SMTP server.
    Host string
    // Port represents the port of the SMTP server.
    Port int
    // Username is the username to use to authenticate to the SMTP server.
    Username string
    // Password is the password to use to authenticate to the SMTP server.
    Password string
    // 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
    // TLSConfig represents the TLS configuration used for the TLS (when the
    // STARTTLS extension is used) or SSL connection.
    TLSConfig *tls.Config
    // StartTLSPolicy represents the TLS security level required to
    // communicate with the SMTP server.
    //
    // This defaults to OpportunisticStartTLS for backwards compatibility,
    // but we recommend MandatoryStartTLS for all modern SMTP servers.
    //
    // This option has no effect if SSL is set to true.
    StartTLSPolicy StartTLSPolicy
    // LocalName is the hostname sent to the SMTP server with the HELO command.
    // By default, "localhost" is sent.
    LocalName string
    // Timeout to use for read/write operations. Defaults to 10 seconds, can
    // be set to 0 to disable timeouts.
    Timeout time.Duration
    // Whether we should retry mailing if the connection returned an error,
    // defaults to true.
    RetryFailure bool
}

func NewDialer ¶

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

NewDialer returns a new SMTP Dialer. The given parameters are used to connect to the SMTP server.

func NewPlainDialer ¶

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

NewPlainDialer returns a new SMTP Dialer. The given parameters are used to connect to the SMTP server.

Deprecated: Use NewDialer instead.

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 ¶

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

type Encoding string

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 ¶

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

type FileSetting func(*file)

func Rename ¶

func Rename(name string) FileSetting

Rename is a file setting to set the name of the attachment if the name is different than the filename on disk.

m.Attach("/tmp/0000146.jpg", mail.Rename("picture.jpg"))

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.

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

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.

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

type Message ¶

Message represents an email.

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

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, settings ...PartSetting)

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. AddAlternative appends the new part to the end of the message. So the plain text part should be added before the HTML part. See http://en.wikipedia.org/wiki/MIME#Alternative

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

func (*Message) AddAlternativeWriter ¶

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

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

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

func (*Message) Attach ¶

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

Attach attaches the files to the email.

m.Attach("/tmp/image.jpg")

func (*Message) AttachReader ¶

func (m *Message) AttachReader(name string, r io.Reader, settings ...FileSetting)

AttachReader attaches a file using an io.Reader

func (*Message) Embed ¶

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

Embed embeds the images to the email.

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

func (*Message) EmbedReader ¶

func (m *Message) EmbedReader(name string, r io.Reader, settings ...FileSetting)

EmbedReader embeds the images to the email.

func (*Message) FormatAddress ¶

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

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

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

func (*Message) FormatDate ¶

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

FormatDate formats a date as a valid RFC 5322 date.

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

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.

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

func (*Message) SetBody ¶

func (m *Message) SetBody(contentType, body string, settings ...PartSetting)

SetBody sets the body of the message. It replaces any content previously set by SetBody, SetBodyWriter, AddAlternative or AddAlternativeWriter.

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

func (*Message) SetBodyWriter ¶

func (m *Message) SetBodyWriter(contentType string, f func(io.Writer) error, settings ...PartSetting)

SetBodyWriter sets the body of the message. It can be useful with the text/template or html/template packages.

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

func (*Message) SetBoundary ¶

func (m *Message) SetBoundary(boundary string)

SetBoundary sets a custom multipart boundary.

func (*Message) SetDateHeader ¶

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

SetDateHeader sets a date to the given header field.

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

func (*Message) SetHeader ¶

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

SetHeader sets a value to the given header field.

m.SetHeader("Subject", "Hello!")

func (*Message) SetHeaders ¶

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

SetHeaders sets the message headers.

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

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 ¶

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

type MessageSetting func(m *Message)

func SetCharset ¶

func SetCharset(charset string) MessageSetting

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

m = mail.NewMessage(mail.SetCharset("ISO-8859-1"))

func SetEncoding ¶

func SetEncoding(enc Encoding) MessageSetting

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

m = mail.NewMessage(mail.SetEncoding(mail.Base64))

type PartSetting ¶

A PartSetting can be used as an argument in Message.SetBody, Message.SetBodyWriter, Message.AddAlternative or Message.AddAlternativeWriter to configure the part added to a message.

type PartSetting func(*part)

func SetPartEncoding ¶

func SetPartEncoding(e Encoding) PartSetting

SetPartEncoding sets the encoding of the part added to the message. By default, parts use the same encoding than the message.

m.SetBody("text/plain", "Hello!", mail.SetPartEncoding(mail.Unencoded))

type SendCloser ¶

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

type SendCloser interface {
    Sender
    Close() error
}

type SendError ¶

A SendError represents the failure to transmit a Message, detailing the cause of the failure and index of the Message within a batch.

type SendError struct {
    // Index specifies the index of the Message within a batch.
    Index uint
    Cause error
}

func (*SendError) Error ¶

func (err *SendError) Error() string

type SendFunc ¶

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

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.

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

func (SendFunc) Send ¶

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

Send calls f(from, to, msg).

type Sender ¶

Sender is the interface that wraps the Send method.

Send sends an email to the given addresses.

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

type StartTLSPolicy ¶

StartTLSPolicy constants are valid values for Dialer.StartTLSPolicy.

type StartTLSPolicy int

const (
    // OpportunisticStartTLS means that SMTP transactions are encrypted if
    // STARTTLS is supported by the SMTP server. Otherwise, messages are
    // sent in the clear. This is the default setting.
    OpportunisticStartTLS StartTLSPolicy = iota
    // MandatoryStartTLS means that SMTP transactions must be encrypted.
    // SMTP transactions are aborted unless STARTTLS is supported by the
    // SMTP server.
    MandatoryStartTLS
    // NoStartTLS means encryption is disabled and messages are sent in the
    // clear.
    NoStartTLS = -1
)

func (*StartTLSPolicy) String ¶

func (policy *StartTLSPolicy) String() string

type StartTLSUnsupportedError ¶

StartTLSUnsupportedError is returned by Dial when connecting to an SMTP server that does not support STARTTLS.

type StartTLSUnsupportedError struct {
    Policy StartTLSPolicy
}

func (StartTLSUnsupportedError) Error ¶

func (e StartTLSUnsupportedError) Error() string