initial commit

1 files changed, 722 insertions, 0 deletions

diff --git a/vendor/github.com/emersion/go-smtp/client.go b/vendor/github.com/emersion/go-smtp/client.go
new file mode 100644
index 0000000..2b455ba
--- /dev/null
+++ b/vendor/github.com/emersion/go-smtp/client.go
@@ -0,0 +1,722 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package smtp
+
+import (
+	"crypto/tls"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/textproto"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-sasl"
+)
+
+// A Client represents a client connection to an SMTP server.
+type Client struct {
+	// Text is the textproto.Conn used by the Client. It is exported to allow for
+	// clients to add extensions.
+	Text *textproto.Conn
+
+	// keep a reference to the connection so it can be used to create a TLS
+	// connection later
+	conn net.Conn
+	// whether the Client is using TLS
+	tls        bool
+	serverName string
+	lmtp       bool
+	// map of supported extensions
+	ext map[string]string
+	// supported auth mechanisms
+	auth       []string
+	localName  string   // the name to use in HELO/EHLO/LHLO
+	didHello   bool     // whether we've said HELO/EHLO/LHLO
+	helloError error    // the error from the hello
+	rcpts      []string // recipients accumulated for the current session
+
+	// Time to wait for command responses (this includes 3xx reply to DATA).
+	CommandTimeout time.Duration
+	// Time to wait for responses after final dot.
+	SubmissionTimeout time.Duration
+
+	// Logger for all network activity.
+	DebugWriter io.Writer
+}
+
+// 30 seconds was chosen as it's the
+// same duration as http.DefaultTransport's timeout.
+var defaultTimeout = 30 * time.Second
+
+// Dial returns a new Client connected to an SMTP server at addr.
+// The addr must include a port, as in "mail.example.com:smtp".
+func Dial(addr string) (*Client, error) {
+	conn, err := net.DialTimeout("tcp", addr, defaultTimeout)
+	if err != nil {
+		return nil, err
+	}
+	host, _, _ := net.SplitHostPort(addr)
+	return NewClient(conn, host)
+}
+
+// DialTLS returns a new Client connected to an SMTP server via TLS at addr.
+// The addr must include a port, as in "mail.example.com:smtps".
+//
+// A nil tlsConfig is equivalent to a zero tls.Config.
+func DialTLS(addr string, tlsConfig *tls.Config) (*Client, error) {
+	tlsDialer := tls.Dialer{
+		NetDialer: &net.Dialer{
+			Timeout: defaultTimeout,
+		},
+		Config: tlsConfig,
+	}
+	conn, err := tlsDialer.Dial("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+	host, _, _ := net.SplitHostPort(addr)
+	return NewClient(conn, host)
+}
+
+// NewClient returns a new Client using an existing connection and host as a
+// server name to be used when authenticating.
+func NewClient(conn net.Conn, host string) (*Client, error) {
+	c := &Client{
+		serverName: host,
+		localName:  "localhost",
+		// As recommended by RFC 5321. For DATA command reply (3xx one) RFC
+		// recommends a slightly shorter timeout but we do not bother
+		// differentiating these.
+		CommandTimeout: 5 * time.Minute,
+		// 10 minutes + 2 minute buffer in case the server is doing transparent
+		// forwarding and also follows recommended timeouts.
+		SubmissionTimeout: 12 * time.Minute,
+	}
+
+	c.setConn(conn)
+
+	// Initial greeting timeout. RFC 5321 recommends 5 minutes.
+	c.conn.SetDeadline(time.Now().Add(5 * time.Minute))
+	defer c.conn.SetDeadline(time.Time{})
+
+	_, _, err := c.Text.ReadResponse(220)
+	if err != nil {
+		c.Text.Close()
+		if protoErr, ok := err.(*textproto.Error); ok {
+			return nil, toSMTPErr(protoErr)
+		}
+		return nil, err
+	}
+
+	return c, nil
+}
+
+// NewClientLMTP returns a new LMTP Client (as defined in RFC 2033) using an
+// existing connection and host as a server name to be used when authenticating.
+func NewClientLMTP(conn net.Conn, host string) (*Client, error) {
+	c, err := NewClient(conn, host)
+	if err != nil {
+		return nil, err
+	}
+	c.lmtp = true
+	return c, nil
+}
+
+// setConn sets the underlying network connection for the client.
+func (c *Client) setConn(conn net.Conn) {
+	c.conn = conn
+
+	var r io.Reader = conn
+	var w io.Writer = conn
+
+	r = &lineLimitReader{
+		R: conn,
+		// Doubled maximum line length per RFC 5321 (Section 4.5.3.1.6)
+		LineLimit: 2000,
+	}
+
+	r = io.TeeReader(r, clientDebugWriter{c})
+	w = io.MultiWriter(w, clientDebugWriter{c})
+
+	rwc := struct {
+		io.Reader
+		io.Writer
+		io.Closer
+	}{
+		Reader: r,
+		Writer: w,
+		Closer: conn,
+	}
+	c.Text = textproto.NewConn(rwc)
+
+	_, isTLS := conn.(*tls.Conn)
+	c.tls = isTLS
+}
+
+// Close closes the connection.
+func (c *Client) Close() error {
+	return c.Text.Close()
+}
+
+// hello runs a hello exchange if needed.
+func (c *Client) hello() error {
+	if !c.didHello {
+		c.didHello = true
+		err := c.ehlo()
+		if err != nil {
+			c.helloError = c.helo()
+		}
+	}
+	return c.helloError
+}
+
+// Hello sends a HELO or EHLO to the server as the given host name.
+// Calling this method is only necessary if the client needs control
+// over the host name used. The client will introduce itself as "localhost"
+// automatically otherwise. If Hello is called, it must be called before
+// any of the other methods.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Hello(localName string) error {
+	if err := validateLine(localName); err != nil {
+		return err
+	}
+	if c.didHello {
+		return errors.New("smtp: Hello called after other methods")
+	}
+	c.localName = localName
+	return c.hello()
+}
+
+// cmd is a convenience function that sends a command and returns the response
+// textproto.Error returned by c.Text.ReadResponse is converted into SMTPError.
+func (c *Client) cmd(expectCode int, format string, args ...interface{}) (int, string, error) {
+	c.conn.SetDeadline(time.Now().Add(c.CommandTimeout))
+	defer c.conn.SetDeadline(time.Time{})
+
+	id, err := c.Text.Cmd(format, args...)
+	if err != nil {
+		return 0, "", err
+	}
+	c.Text.StartResponse(id)
+	defer c.Text.EndResponse(id)
+	code, msg, err := c.Text.ReadResponse(expectCode)
+	if err != nil {
+		if protoErr, ok := err.(*textproto.Error); ok {
+			smtpErr := toSMTPErr(protoErr)
+			return code, smtpErr.Message, smtpErr
+		}
+		return code, msg, err
+	}
+	return code, msg, nil
+}
+
+// helo sends the HELO greeting to the server. It should be used only when the
+// server does not support ehlo.
+func (c *Client) helo() error {
+	c.ext = nil
+	_, _, err := c.cmd(250, "HELO %s", c.localName)
+	return err
+}
+
+// ehlo sends the EHLO (extended hello) greeting to the server. It
+// should be the preferred greeting for servers that support it.
+func (c *Client) ehlo() error {
+	cmd := "EHLO"
+	if c.lmtp {
+		cmd = "LHLO"
+	}
+
+	_, msg, err := c.cmd(250, "%s %s", cmd, c.localName)
+	if err != nil {
+		return err
+	}
+	ext := make(map[string]string)
+	extList := strings.Split(msg, "\n")
+	if len(extList) > 1 {
+		extList = extList[1:]
+		for _, line := range extList {
+			args := strings.SplitN(line, " ", 2)
+			if len(args) > 1 {
+				ext[args[0]] = args[1]
+			} else {
+				ext[args[0]] = ""
+			}
+		}
+	}
+	if mechs, ok := ext["AUTH"]; ok {
+		c.auth = strings.Split(mechs, " ")
+	}
+	c.ext = ext
+	return err
+}
+
+// StartTLS sends the STARTTLS command and encrypts all further communication.
+// Only servers that advertise the STARTTLS extension support this function.
+//
+// A nil config is equivalent to a zero tls.Config.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) StartTLS(config *tls.Config) error {
+	if err := c.hello(); err != nil {
+		return err
+	}
+	_, _, err := c.cmd(220, "STARTTLS")
+	if err != nil {
+		return err
+	}
+	if config == nil {
+		config = &tls.Config{}
+	}
+	if config.ServerName == "" {
+		// Make a copy to avoid polluting argument
+		config = config.Clone()
+		config.ServerName = c.serverName
+	}
+	if testHookStartTLS != nil {
+		testHookStartTLS(config)
+	}
+	c.setConn(tls.Client(c.conn, config))
+	return c.ehlo()
+}
+
+// TLSConnectionState returns the client's TLS connection state.
+// The return values are their zero values if StartTLS did
+// not succeed.
+func (c *Client) TLSConnectionState() (state tls.ConnectionState, ok bool) {
+	tc, ok := c.conn.(*tls.Conn)
+	if !ok {
+		return
+	}
+	return tc.ConnectionState(), true
+}
+
+// Verify checks the validity of an email address on the server.
+// If Verify returns nil, the address is valid. A non-nil return
+// does not necessarily indicate an invalid address. Many servers
+// will not verify addresses for security reasons.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Verify(addr string) error {
+	if err := validateLine(addr); err != nil {
+		return err
+	}
+	if err := c.hello(); err != nil {
+		return err
+	}
+	_, _, err := c.cmd(250, "VRFY %s", addr)
+	return err
+}
+
+// Auth authenticates a client using the provided authentication mechanism.
+// Only servers that advertise the AUTH extension support this function.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Auth(a sasl.Client) error {
+	if err := c.hello(); err != nil {
+		return err
+	}
+	encoding := base64.StdEncoding
+	mech, resp, err := a.Start()
+	if err != nil {
+		return err
+	}
+	resp64 := make([]byte, encoding.EncodedLen(len(resp)))
+	encoding.Encode(resp64, resp)
+	code, msg64, err := c.cmd(0, strings.TrimSpace(fmt.Sprintf("AUTH %s %s", mech, resp64)))
+	for err == nil {
+		var msg []byte
+		switch code {
+		case 334:
+			msg, err = encoding.DecodeString(msg64)
+		case 235:
+			// the last message isn't base64 because it isn't a challenge
+			msg = []byte(msg64)
+		default:
+			err = toSMTPErr(&textproto.Error{Code: code, Msg: msg64})
+		}
+		if err == nil {
+			if code == 334 {
+				resp, err = a.Next(msg)
+			} else {
+				resp = nil
+			}
+		}
+		if err != nil {
+			// abort the AUTH
+			c.cmd(501, "*")
+			break
+		}
+		if resp == nil {
+			break
+		}
+		resp64 = make([]byte, encoding.EncodedLen(len(resp)))
+		encoding.Encode(resp64, resp)
+		code, msg64, err = c.cmd(0, string(resp64))
+	}
+	return err
+}
+
+// Mail issues a MAIL command to the server using the provided email address.
+// If the server supports the 8BITMIME extension, Mail adds the BODY=8BITMIME
+// parameter.
+// This initiates a mail transaction and is followed by one or more Rcpt calls.
+//
+// If opts is not nil, MAIL arguments provided in the structure will be added
+// to the command. Handling of unsupported options depends on the extension.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Mail(from string, opts *MailOptions) error {
+	if err := validateLine(from); err != nil {
+		return err
+	}
+	if err := c.hello(); err != nil {
+		return err
+	}
+	cmdStr := "MAIL FROM:<%s>"
+	if _, ok := c.ext["8BITMIME"]; ok {
+		cmdStr += " BODY=8BITMIME"
+	}
+	if _, ok := c.ext["SIZE"]; ok && opts != nil && opts.Size != 0 {
+		cmdStr += " SIZE=" + strconv.Itoa(opts.Size)
+	}
+	if opts != nil && opts.RequireTLS {
+		if _, ok := c.ext["REQUIRETLS"]; ok {
+			cmdStr += " REQUIRETLS"
+		} else {
+			return errors.New("smtp: server does not support REQUIRETLS")
+		}
+	}
+	if opts != nil && opts.UTF8 {
+		if _, ok := c.ext["SMTPUTF8"]; ok {
+			cmdStr += " SMTPUTF8"
+		} else {
+			return errors.New("smtp: server does not support SMTPUTF8")
+		}
+	}
+	if opts != nil && opts.Auth != nil {
+		if _, ok := c.ext["AUTH"]; ok {
+			cmdStr += " AUTH=" + encodeXtext(*opts.Auth)
+		}
+		// We can safely discard parameter if server does not support AUTH.
+	}
+	_, _, err := c.cmd(250, cmdStr, from)
+	return err
+}
+
+// Rcpt issues a RCPT command to the server using the provided email address.
+// A call to Rcpt must be preceded by a call to Mail and may be followed by
+// a Data call or another Rcpt call.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Rcpt(to string) error {
+	if err := validateLine(to); err != nil {
+		return err
+	}
+	if _, _, err := c.cmd(25, "RCPT TO:<%s>", to); err != nil {
+		return err
+	}
+	c.rcpts = append(c.rcpts, to)
+	return nil
+}
+
+type dataCloser struct {
+	c *Client
+	io.WriteCloser
+	statusCb func(rcpt string, status *SMTPError)
+	closed   bool
+}
+
+func (d *dataCloser) Close() error {
+	if d.closed {
+		return fmt.Errorf("smtp: data writer closed twice")
+	}
+
+	if err := d.WriteCloser.Close(); err != nil {
+		return err
+	}
+
+	d.c.conn.SetDeadline(time.Now().Add(d.c.SubmissionTimeout))
+	defer d.c.conn.SetDeadline(time.Time{})
+
+	expectedResponses := len(d.c.rcpts)
+	if d.c.lmtp {
+		for expectedResponses > 0 {
+			rcpt := d.c.rcpts[len(d.c.rcpts)-expectedResponses]
+			if _, _, err := d.c.Text.ReadResponse(250); err != nil {
+				if protoErr, ok := err.(*textproto.Error); ok {
+					if d.statusCb != nil {
+						d.statusCb(rcpt, toSMTPErr(protoErr))
+					}
+				} else {
+					return err
+				}
+			} else if d.statusCb != nil {
+				d.statusCb(rcpt, nil)
+			}
+			expectedResponses--
+		}
+	} else {
+		_, _, err := d.c.Text.ReadResponse(250)
+		if err != nil {
+			if protoErr, ok := err.(*textproto.Error); ok {
+				return toSMTPErr(protoErr)
+			}
+			return err
+		}
+	}
+
+	d.closed = true
+	return nil
+}
+
+// Data issues a DATA command to the server and returns a writer that
+// can be used to write the mail headers and body. The caller should
+// close the writer before calling any more methods on c. A call to
+// Data must be preceded by one or more calls to Rcpt.
+//
+// If server returns an error, it will be of type *SMTPError.
+func (c *Client) Data() (io.WriteCloser, error) {
+	_, _, err := c.cmd(354, "DATA")
+	if err != nil {
+		return nil, err
+	}
+	return &dataCloser{c: c, WriteCloser: c.Text.DotWriter()}, nil
+}
+
+// LMTPData is the LMTP-specific version of the Data method. It accepts a callback
+// that will be called for each status response received from the server.
+//
+// Status callback will receive a SMTPError argument for each negative server
+// reply and nil for each positive reply. I/O errors will not be reported using
+// callback and instead will be returned by the Close method of io.WriteCloser.
+// Callback will be called for each successfull Rcpt call done before in the
+// same order.
+func (c *Client) LMTPData(statusCb func(rcpt string, status *SMTPError)) (io.WriteCloser, error) {
+	if !c.lmtp {
+		return nil, errors.New("smtp: not a LMTP client")
+	}
+
+	_, _, err := c.cmd(354, "DATA")
+	if err != nil {
+		return nil, err
+	}
+	return &dataCloser{c: c, WriteCloser: c.Text.DotWriter(), statusCb: statusCb}, nil
+}
+
+// SendMail will use an existing connection to send an email from
+// address from, to addresses to, with message r.
+//
+// This function does not start TLS, nor does it perform authentication. Use
+// StartTLS and Auth before-hand if desirable.
+//
+// The addresses in the to parameter are the SMTP RCPT addresses.
+//
+// The r parameter should be an RFC 822-style email with headers
+// first, a blank line, and then the message body. The lines of r
+// should be CRLF terminated. The r headers should usually include
+// fields such as "From", "To", "Subject", and "Cc".  Sending "Bcc"
+// messages is accomplished by including an email address in the to
+// parameter but not including it in the r headers.
+func (c *Client) SendMail(from string, to []string, r io.Reader) error {
+	var err error
+
+	if err = c.Mail(from, nil); err != nil {
+		return err
+	}
+	for _, addr := range to {
+		if err = c.Rcpt(addr); err != nil {
+			return err
+		}
+	}
+	w, err := c.Data()
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(w, r)
+	if err != nil {
+		return err
+	}
+	err = w.Close()
+	if err != nil {
+		return err
+	}
+	return c.Quit()
+}
+
+var testHookStartTLS func(*tls.Config) // nil, except for tests
+
+// SendMail connects to the server at addr, switches to TLS, authenticates with
+// the optional SASL client, and then sends an email from address from, to
+// addresses to, with message r. The addr must include a port, as in
+// "mail.example.com:smtp".
+//
+// The addresses in the to parameter are the SMTP RCPT addresses.
+//
+// The r parameter should be an RFC 822-style email with headers
+// first, a blank line, and then the message body. The lines of r
+// should be CRLF terminated. The r headers should usually include
+// fields such as "From", "To", "Subject", and "Cc".  Sending "Bcc"
+// messages is accomplished by including an email address in the to
+// parameter but not including it in the r headers.
+//
+// SendMail is intended to be used for very simple use-cases. If you want to
+// customize SendMail's behavior, use a Client instead.
+//
+// The SendMail function and the go-smtp package are low-level
+// mechanisms and provide no support for DKIM signing (see go-msgauth), MIME
+// attachments (see the mime/multipart package or the go-message package), or
+// other mail functionality.
+func SendMail(addr string, a sasl.Client, from string, to []string, r io.Reader) error {
+	if err := validateLine(from); err != nil {
+		return err
+	}
+	for _, recp := range to {
+		if err := validateLine(recp); err != nil {
+			return err
+		}
+	}
+	c, err := Dial(addr)
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+
+	if err = c.hello(); err != nil {
+		return err
+	}
+	if ok, _ := c.Extension("STARTTLS"); !ok {
+		return errors.New("smtp: server doesn't support STARTTLS")
+	}
+	if err = c.StartTLS(nil); err != nil {
+		return err
+	}
+	if a != nil && c.ext != nil {
+		if _, ok := c.ext["AUTH"]; !ok {
+			return errors.New("smtp: server doesn't support AUTH")
+		}
+		if err = c.Auth(a); err != nil {
+			return err
+		}
+	}
+	return c.SendMail(from, to, r)
+}
+
+// Extension reports whether an extension is support by the server.
+// The extension name is case-insensitive. If the extension is supported,
+// Extension also returns a string that contains any parameters the
+// server specifies for the extension.
+func (c *Client) Extension(ext string) (bool, string) {
+	if err := c.hello(); err != nil {
+		return false, ""
+	}
+	if c.ext == nil {
+		return false, ""
+	}
+	ext = strings.ToUpper(ext)
+	param, ok := c.ext[ext]
+	return ok, param
+}
+
+// Reset sends the RSET command to the server, aborting the current mail
+// transaction.
+func (c *Client) Reset() error {
+	if err := c.hello(); err != nil {
+		return err
+	}
+	if _, _, err := c.cmd(250, "RSET"); err != nil {
+		return err
+	}
+	c.rcpts = nil
+	return nil
+}
+
+// Noop sends the NOOP command to the server. It does nothing but check
+// that the connection to the server is okay.
+func (c *Client) Noop() error {
+	if err := c.hello(); err != nil {
+		return err
+	}
+	_, _, err := c.cmd(250, "NOOP")
+	return err
+}
+
+// Quit sends the QUIT command and closes the connection to the server.
+//
+// If Quit fails the connection is not closed, Close should be used
+// in this case.
+func (c *Client) Quit() error {
+	if err := c.hello(); err != nil {
+		return err
+	}
+	_, _, err := c.cmd(221, "QUIT")
+	if err != nil {
+		return err
+	}
+	return c.Text.Close()
+}
+
+func parseEnhancedCode(s string) (EnhancedCode, error) {
+	parts := strings.Split(s, ".")
+	if len(parts) != 3 {
+		return EnhancedCode{}, fmt.Errorf("wrong amount of enhanced code parts")
+	}
+
+	code := EnhancedCode{}
+	for i, part := range parts {
+		num, err := strconv.Atoi(part)
+		if err != nil {
+			return code, err
+		}
+		code[i] = num
+	}
+	return code, nil
+}
+
+// toSMTPErr converts textproto.Error into SMTPError, parsing
+// enhanced status code if it is present.
+func toSMTPErr(protoErr *textproto.Error) *SMTPError {
+	if protoErr == nil {
+		return nil
+	}
+	smtpErr := &SMTPError{
+		Code:    protoErr.Code,
+		Message: protoErr.Msg,
+	}
+
+	parts := strings.SplitN(protoErr.Msg, " ", 2)
+	if len(parts) != 2 {
+		return smtpErr
+	}
+
+	enchCode, err := parseEnhancedCode(parts[0])
+	if err != nil {
+		return smtpErr
+	}
+
+	msg := parts[1]
+
+	// Per RFC 2034, enhanced code should be prepended to each line.
+	msg = strings.ReplaceAll(msg, "\n"+parts[0]+" ", "\n")
+
+	smtpErr.EnhancedCode = enchCode
+	smtpErr.Message = msg
+	return smtpErr
+}
+
+type clientDebugWriter struct {
+	c *Client
+}
+
+func (cdw clientDebugWriter) Write(b []byte) (int, error) {
+	if cdw.c.DebugWriter == nil {
+		return len(b), nil
+	}
+	return cdw.c.DebugWriter.Write(b)
+}