README
¶
Go Simple Mail
The best way to send emails in Go with SMTP Keep Alive and Timeout for Connect and Send.
IMPORTANT
Examples in this README are for v2.2.0 and above. Examples for older versions can be found here.
Go 1.13+ is required.
Breaking change in 2.2.0: The signature of SetBody and AddAlternative used
to accept strings ("text/html" and "text/plain") and not require on of the
contentType constants (TextHTML or TextPlain). Upgrading, while not
quite following semantic versioning, is quite simple:
email := mail.NewMSG()
- email.SetBody("text/html", htmlBody)
- email.AddAlternative("text/plain", plainBody)
+ email.SetBody(mail.TextHTML, htmlBody)
+ email.AddAlternative(mail.TextPlain, plainBody)
Introduction
Go Simple Mail is a simple and efficient package to send emails. It is well tested and documented.
Go Simple Mail 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.
This package contains (and is based on) two packages by Joe Grasse:
- https://github.com/joegrasse/mail (unmaintained since Jun 29, 2018), and
- https://github.com/joegrasse/mime (unmaintained since Oct 1, 2015).
A lot of changes in Go Simple Mail were sent with not response.
Features
Go Simple Mail supports:
- Multiple Attachments with path
- Multiple Attachments in base64
- Multiple Attachments from bytes (since v2.6.0)
- Inline attachments from file, base64 and bytes (bytes since v2.6.0)
- Multiple Recipients
- Priority
- Reply to
- Set sender
- Set from
- Allow sending mail with different envelope from (since v2.7.0)
- Embedded images
- HTML and text templates
- Automatic encoding of special characters
- SSL/TLS and STARTTLS
- Unencrypted connection (not recommended)
- Sending multiple emails with the same SMTP connection (Keep Alive or Persistent Connection)
- Timeout for connect to a SMTP Server
- Timeout for send an email
- Return Path
- Alternative Email Body
- CC and BCC
- Add Custom Headers in Message
- Send NOOP, RESET, QUIT and CLOSE to SMTP client
- PLAIN, LOGIN and CRAM-MD5 Authentication (since v2.3.0)
- AUTO Authentication (since v2.14.0)
- Allow connect to SMTP without authentication (since v2.10.0)
- Custom TLS Configuration (since v2.5.0)
- Send a RFC822 formatted message (since v2.8.0)
- Send from localhost (yes, Go standard SMTP package cannot do that because... WTF Google!)
- Support text/calendar content type body (since v2.11.0)
- Support add a List-Unsubscribe header (since v2.11.0)
- Support to add a DKIM signarure (since v2.11.0)
- Support to send using custom connection, ideal for proxy (since v2.15.0)
- Support Delivery Status Notification (DSN) (since v2.16.0)
- Support text/x-amp-html content type body (since v2.16.0)
Documentation
https://pkg.go.dev/github.com/xhit/go-simple-mail/v2?tab=doc
Note 1: by default duplicated recipients throws an error, from v2.13.0 you can use email.AllowDuplicateAddress = true to avoid the check.
Note 2: by default Bcc header is not set in email. From v2.14.0 you can use email.AddBccToHeader = true to add this.
Download
This package uses go modules.
$ go get github.com/xhit/go-simple-mail/v2
Usage
package main
import (
"log"
mail "github.com/xhit/go-simple-mail/v2"
"github.com/toorop/go-dkim"
)
const htmlBody = `<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Hello Gophers!</title>
</head>
<body>
<p>This is the <b>Go gopher</b>.</p>
<p><img src="cid:Gopher.png" alt="Go gopher" /></p>
<p>Image created by Renee French</p>
</body>
</html>`
const privateKey = `-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----`
func main() {
server := mail.NewSMTPClient()
// SMTP Server
server.Host = "smtp.example.com"
server.Port = 587
server.Username = "test@example.com"
server.Password = "examplepass"
server.Encryption = mail.EncryptionSTARTTLS
// You can specified authentication type:
// - AUTO (default)
// - PLAIN
// - LOGIN
// - CRAM-MD5
// - None
// server.Authentication = mail.AuthAuto
// Variable to keep alive connection
server.KeepAlive = false
// Timeout for connect to SMTP Server
server.ConnectTimeout = 10 * time.Second
// Timeout for send the data and wait respond
server.SendTimeout = 10 * time.Second
// Set TLSConfig to provide custom TLS configuration. For example,
// to skip TLS verification (useful for testing):
server.TLSConfig = &tls.Config{InsecureSkipVerify: true}
// SMTP client
smtpClient,err := server.Connect()
if err != nil{
log.Fatal(err)
}
// New email simple html with inline and CC
email := mail.NewMSG()
email.SetFrom("From Example <nube@example.com>").
AddTo("xhit@example.com").
AddCc("otherto@example.com").
SetSubject("New Go Email").
SetListUnsubscribe("<mailto:unsubscribe@example.com?subject=https://example.com/unsubscribe>")
email.SetBody(mail.TextHTML, htmlBody)
// also you can add body from []byte with SetBodyData, example:
// email.SetBodyData(mail.TextHTML, []byte(htmlBody))
// or alternative part
// email.AddAlternativeData(mail.TextHTML, []byte(htmlBody))
// add inline
email.Attach(&mail.File{FilePath: "/path/to/image.png", Name:"Gopher.png", Inline: true})
// also you can set Delivery Status Notification (DSN) (only is set when server supports DSN)
email.SetDSN([]mail.DSN{mail.SUCCESS, mail.FAILURE}, false)
// you can add dkim signature to the email.
// to add dkim, you need a private key already created one.
if privateKey != "" {
options := dkim.NewSigOptions()
options.PrivateKey = []byte(privateKey)
options.Domain = "example.com"
options.Selector = "default"
options.SignatureExpireIn = 3600
options.Headers = []string{"from", "date", "mime-version", "received", "received"}
options.AddSignatureTimestamp = true
options.Canonicalization = "relaxed/relaxed"
email.SetDkim(options)
}
// always check error after send
if email.Error != nil{
log.Fatal(email.Error)
}
// Call Send and pass the client
err = email.Send(smtpClient)
if err != nil {
log.Println(err)
} else {
log.Println("Email Sent")
}
}
Send multiple emails in same connection
//Set your smtpClient struct to keep alive connection
server.KeepAlive = true
for _, to := range []string{
"to1@example1.com",
"to3@example2.com",
"to4@example3.com",
} {
// New email simple html with inline and CC
email := mail.NewMSG()
email.SetFrom("From Example <nube@example.com>").
AddTo(to).
SetSubject("New Go Email")
email.SetBody(mail.TextHTML, htmlBody)
// add inline
email.Attach(&mail.File{FilePath: "/path/to/image.png", Name:"Gopher.png", Inline: true})
// always check error after send
if email.Error != nil{
log.Fatal(email.Error)
}
// Call Send and pass the client
err = email.Send(smtpClient)
if err != nil {
log.Println(err)
} else {
log.Println("Email Sent")
}
}
Send with custom connection
It's possible to use a custom connection with custom dieler, like a dialer that uses a proxy server, etc...
With this, these servers params are ignored: Host, Port. You have total control of the connection.
Example using a conn for proxy:
package main
import (
"crypto/tls"
"fmt"
"log"
"net"
mail "github.com/xhit/go-simple-mail/v2"
"golang.org/x/net/proxy"
)
func main() {
server := mail.NewSMTPClient()
host := "smtp.example.com"
port := 587
proxyAddr := "proxy.server"
conn, err := getCustomConnWithProxy(proxyAddr, host, port)
if err != nil {
log.Fatal(err)
}
server.Username = "test@example.com"
server.Password = "examplepass"
server.Encryption = mail.EncryptionSTARTTLS
server.CustomConn = conn
smtpClient, err := server.Connect()
if err != nil {
log.Fatal(err)
}
email := mail.NewMSG()
err = email.SetFrom("From Example <nube@example.com>").AddTo("xhit@example.com").Send(smtpClient)
if err != nil {
log.Fatal(err)
}
}
func getCustomConnWithProxy(proxyAddr, host string, port int) (net.Conn, error) {
dial, err := proxy.SOCKS5("tcp", proxyAddr, nil, proxy.Direct)
if err != nil {
return nil, err
}
dialer, err := dial.Dial("tcp", fmt.Sprintf("%s:%d", host, port))
if err != nil {
return nil, err
}
conf := &tls.Config{ServerName: host}
conn := tls.Client(dialer, conf)
return conn, nil
}
More examples
Documentation
¶
Index ¶
- Constants
- func SendMessage(from string, recipients []string, msg string, client *SMTPClient) error
- type AuthType
- type ContentType
- type DSN
- type Email
- func (email *Email) AddAddresses(header string, addresses ...string) *Email
- func (email *Email) AddAlternative(contentType ContentType, body string) *Email
- func (email *Email) AddAlternativeData(contentType ContentType, body []byte) *Email
- func (email *Email) AddAttachment(file string, name ...string) *Email
- func (email *Email) AddAttachmentBase64(b64File, name string) *Email
- func (email *Email) AddAttachmentData(data []byte, filename, mimeType string) *Email
- func (email *Email) AddBcc(addresses ...string) *Email
- func (email *Email) AddCc(addresses ...string) *Email
- func (email *Email) AddHeader(header string, values ...string) *Email
- func (email *Email) AddHeaders(headers textproto.MIMEHeader) *Email
- func (email *Email) AddInline(file string, name ...string) *Email
- func (email *Email) AddInlineBase64(b64File, name, mimeType string) *Email
- func (email *Email) AddInlineData(data []byte, filename, mimeType string) *Email
- func (email *Email) AddTo(addresses ...string) *Email
- func (email *Email) Attach(file *File) *Email
- func (email *Email) GetError() error
- func (email *Email) GetFrom() string
- func (email *Email) GetMessage() string
- func (email *Email) GetRecipients() []string
- func (email *Email) Send(client *SMTPClient) error
- func (email *Email) SendEnvelopeFrom(from string, client *SMTPClient) error
- func (email *Email) SetBody(contentType ContentType, body string) *Email
- func (email *Email) SetBodyData(contentType ContentType, body []byte) *Email
- func (email *Email) SetDSN(dsn []DSN, preserveOriginalRecipient bool) *Email
- func (email *Email) SetDate(dateTime string) *Email
- func (email *Email) SetDkim(options dkim.SigOptions) *Email
- func (email *Email) SetFrom(address string) *Email
- func (email *Email) SetListUnsubscribe(address string) *Email
- func (email *Email) SetPriority(priority Priority) *Email
- func (email *Email) SetReplyTo(address string) *Email
- func (email *Email) SetReturnPath(address string) *Email
- func (email *Email) SetSender(address string) *Email
- func (email *Email) SetSubject(subject string) *Email
- type Encryption
- type File
- type Priority
- type SMTPClient
- type SMTPServer
Constants ¶
const ( // EncodingNone turns off encoding on the message body EncodingNone encoding = iota // EncodingBase64 sets the message body encoding to base64 EncodingBase64 // EncodingQuotedPrintable sets the message body encoding to quoted-printable EncodingQuotedPrintable )
Variables ¶
This section is empty.
Functions ¶
func SendMessage ¶ added in v2.8.0
func SendMessage(from string, recipients []string, msg string, client *SMTPClient) error
SendMessage sends a message (a RFC822 formatted message) 'from' must be an email address, recipients must be a slice of email address
Types ¶
type AuthType ¶ added in v2.10.0
type AuthType int
const ( // AuthPlain implements the PLAIN authentication AuthPlain AuthType = iota // AuthLogin implements the LOGIN authentication AuthLogin // AuthCRAMMD5 implements the CRAM-MD5 authentication AuthCRAMMD5 // AuthNone for SMTP servers without authentication AuthNone // AuthAuto (default) use the first AuthType of the list of returned types supported by SMTP AuthAuto )
type ContentType ¶ added in v2.12.0
type ContentType int
const ( // TextPlain sets body type to text/plain in message body TextPlain ContentType = iota // TextHTML sets body type to text/html in message body TextHTML // TextCalendar sets body type to text/calendar in message body TextCalendar // TextAMP sets body type to text/x-amp-html in message body TextAMP )
type DSN ¶ added in v2.16.0
type DSN int
DSN notifications
- 'NEVER' under no circumstances a DSN must be returned to the sender. If you use NEVER all other notifications will be ignored.
- 'SUCCESS' will notify you when your mail has arrived at its destination.
- 'FAILURE' will arrive if an error occurred during delivery.
- 'DELAY' will notify you if there is an unusual delay in delivery, but the actual delivery's outcome (success or failure) is not yet decided.
see https://tools.ietf.org/html/rfc3461 See section 4.1 for more information about NOTIFY
type Email ¶
type Email struct {
Charset string
Encoding encoding
Error error
SMTPServer *smtpClient
DkimMsg string
AllowDuplicateAddress bool
AddBccToHeader bool
// contains filtered or unexported fields
}
Email represents an email message.
func NewMSG ¶
func NewMSG() *Email
NewMSG creates a new email. It uses UTF-8 by default. All charsets: http://webcheatsheet.com/HTML/character_sets_list.php
func (*Email) AddAddresses ¶
AddAddresses allows you to add addresses to the specified address header.
func (*Email) AddAlternative ¶
func (email *Email) AddAlternative(contentType ContentType, body string) *Email
AddAlternative allows you to add alternative parts to the body of the email message. This is most commonly used to add an html version in addition to a plain text version that was already added with SetBody.
func (*Email) AddAlternativeData ¶ added in v2.11.0
func (email *Email) AddAlternativeData(contentType ContentType, body []byte) *Email
AddAlternativeData allows you to add alternative parts to the body of the email message. This is most commonly used to add an html version in addition to a plain text version that was already added with SetBody.
func (*Email) AddAttachment ¶
AddAttachment. DEPRECATED. Use Attach method. Allows you to add an attachment to the email message. You can optionally provide a different name for the file.
func (*Email) AddAttachmentBase64 ¶
AddAttachmentBase64. DEPRECATED. Use Attach method. Allows you to add an attachment in base64 to the email message. You need provide a name for the file.
func (*Email) AddAttachmentData ¶ added in v2.6.0
AddAttachmentData. DEPRECATED. Use Attach method. Allows you to add an in-memory attachment to the email message.
func (*Email) AddBcc ¶
AddBcc adds a Bcc address. You can provide multiple addresses at the same time.
func (*Email) AddHeaders ¶
func (email *Email) AddHeaders(headers textproto.MIMEHeader) *Email
AddHeaders is used to add multiple headers at once
func (*Email) AddInline ¶
AddInline. DEPRECATED. Use Attach method. Allows you to add an inline attachment to the email message. You can optionally provide a different name for the file.
func (*Email) AddInlineBase64 ¶ added in v2.9.0
AddInlineBase64. DEPRECATED. Use Attach method. Allows you to add an inline in-memory base64 encoded attachment to the email message. You need provide a name for the file. If mimeType is an empty string, attachment mime type will be deduced from the file name extension and defaults to application/octet-stream.
func (*Email) AddInlineData ¶ added in v2.6.0
AddInlineData. DEPRECATED. Use Attach method. Allows you to add an inline in-memory attachment to the email message.
func (*Email) Attach ¶ added in v2.9.0
Attach allows you to add an attachment to the email message. The attachment can be inlined
func (*Email) GetMessage ¶
GetMessage builds and returns the email message (RFC822 formatted message)
func (*Email) GetRecipients ¶ added in v2.8.0
GetRecipients returns a slice of recipients emails
func (*Email) Send ¶
func (email *Email) Send(client *SMTPClient) error
Send sends the composed email
func (*Email) SendEnvelopeFrom ¶ added in v2.7.0
func (email *Email) SendEnvelopeFrom(from string, client *SMTPClient) error
SendEnvelopeFrom sends the composed email with envelope sender. 'from' must be an email address.
func (*Email) SetBody ¶
func (email *Email) SetBody(contentType ContentType, body string) *Email
SetBody sets the body of the email message.
func (*Email) SetBodyData ¶ added in v2.9.0
func (email *Email) SetBodyData(contentType ContentType, body []byte) *Email
SetBodyData sets the body of the email message from []byte
func (*Email) SetDSN ¶ added in v2.16.0
SetDSN sets the delivery status notification list, only is set when SMTP server supports DSN extension
To preserve the original recipient of an email message, for example, if it is forwarded to another address, set preserveOriginalRecipient to true
func (*Email) SetDate ¶
SetDate sets the date header to the provided date/time. The format of the string should be YYYY-MM-DD HH:MM:SS Time Zone.
Example: SetDate("2015-04-28 10:32:00 CDT")
func (*Email) SetDkim ¶ added in v2.11.0
SetDkim adds DomainKey signature to the email message (header+body)
func (*Email) SetListUnsubscribe ¶ added in v2.11.0
SetListUnsubscribe sets the Unsubscribe address.
func (*Email) SetPriority ¶
SetPriority sets the email message Priority. Use with either "High" or "Low".
func (*Email) SetReplyTo ¶
SetReplyTo sets the Reply-To address.
func (*Email) SetReturnPath ¶
SetReturnPath sets the Return-Path address. This is most often used to send bounced emails to a different email address.
func (*Email) SetSubject ¶
SetSubject sets the subject of the email message.
type Encryption ¶ added in v2.8.0
type Encryption int
Encryption type to enum encryption types (None, SSL/TLS, STARTTLS)
const ( // EncryptionNone uses no encryption when sending email EncryptionNone Encryption = iota // EncryptionSSL: DEPRECATED. Use EncryptionSSLTLS. Sets encryption type to SSL/TLS when sending email EncryptionSSL // EncryptionTLS: DEPRECATED. Use EncryptionSTARTTLS. sets encryption type to STARTTLS when sending email EncryptionTLS // EncryptionSSLTLS sets encryption type to SSL/TLS when sending email EncryptionSSLTLS // EncryptionSTARTTLS sets encryption type to STARTTLS when sending email EncryptionSTARTTLS )
func (Encryption) String ¶ added in v2.8.0
func (encryption Encryption) String() string
type File ¶ added in v2.9.0
type File struct {
// FilePath is the path of the file to attach.
FilePath string
// Name is the name of file in attachment. Required for Data and B64Data. Optional for FilePath.
Name string
// MimeType of attachment. If empty then is obtained from Name (if not empty) or FilePath. If cannot obtained, application/octet-stream is set.
MimeType string
// B64Data is the base64 string to attach.
B64Data string
// Data is the []byte of file to attach.
Data []byte
// Inline defines if attachment is inline or not.
Inline bool
}
File represents the file that can be added to the email message. You can add attachment from file in path, from base64 string or from []byte. You can define if attachment is inline or not. Only one, Data, B64Data or FilePath is supported. If multiple are set, then the first in that order is used.
type SMTPClient ¶
type SMTPClient struct {
Client *smtpClient
SendTimeout time.Duration
KeepAlive bool
// contains filtered or unexported fields
}
SMTPClient represents a SMTP Client for send email
func (*SMTPClient) Noop ¶
func (smtpClient *SMTPClient) Noop() error
Noop send NOOP command to smtp client
func (*SMTPClient) Quit ¶
func (smtpClient *SMTPClient) Quit() error
Quit send QUIT command to smtp client
func (*SMTPClient) Reset ¶
func (smtpClient *SMTPClient) Reset() error
Reset send RSET command to smtp client
type SMTPServer ¶
type SMTPServer struct {
Authentication AuthType
Encryption Encryption
Username string
Password string
Helo string
ConnectTimeout time.Duration
SendTimeout time.Duration
Host string
Port int
KeepAlive bool
TLSConfig *tls.Config
// use custom dialer
CustomConn net.Conn
}
SMTPServer represents a SMTP Server If authentication is CRAM-MD5 then the Password is the Secret
func NewSMTPClient ¶
func NewSMTPClient() *SMTPServer
NewSMTPClient returns the client for send email
func (*SMTPServer) Connect ¶
func (server *SMTPServer) Connect() (*SMTPClient, error)
Connect returns the smtp client
func (*SMTPServer) GetEncryptionType ¶ added in v2.8.0
func (server *SMTPServer) GetEncryptionType() Encryption
GetEncryptionType returns the encryption type used to connect to SMTP server
Source Files