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Merge pull request #47 from wneessen/DSN

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Implemented DSNs as described in RFC 1891
This commit is contained in:
Winni Neessen 2022-09-12 09:40:16 +02:00 committed by GitHub
commit f4cdc61dd0
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3 changed files with 477 additions and 27 deletions
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2
README.md
View file

@ -43,7 +43,7 @@ Some of the features of this library:
* [X] Support for attachments and inline embeds (from file system, `io.Reader` or `embed.FS`)
* [X] Support for different encodings
* [X] Support sending mails via a local sendmail command
* [X] Support for requestng MDNs
* [X] Support for requestng MDNs (RFC 8098) and DSNs (RFC 1891)
* [X] Message object satisfies `io.WriteTo` and `io.Reader` interfaces
* [X] Support for Go's `html/template` and `text/template` (as message body, alternative part or attachment/emebed)
* [X] Output to file support which allows storing mail messages as e. g. `.eml` files to disk to open them in a MUA

271
client.go
View file

@ -33,14 +33,89 @@ const (
DefaultTLSMinVersion = tls.VersionTLS12
)
// DSNMailReturnOption is a type to define which MAIL RET option is used when a DSN
// is requested
type DSNMailReturnOption string
// DSNRcptNotifyOption is a type to define which RCPT NOTIFY option is used when a DSN
// is requested
type DSNRcptNotifyOption string
const (
// DSNMailReturnHeadersOnly requests that only the headers of the message be returned.
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.3
DSNMailReturnHeadersOnly DSNMailReturnOption = "HDRS"
// DSNMailReturnFull requests that the entire message be returned in any "failed"
// delivery status notification issued for this recipient
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.3
DSNMailReturnFull DSNMailReturnOption = "FULL"
// DSNRcptNotifyNever requests that a DSN not be returned to the sender under
// any conditions.
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.1
DSNRcptNotifyNever DSNRcptNotifyOption = "NEVER"
// DSNRcptNotifySuccess requests that a DSN be issued on successful delivery
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.1
DSNRcptNotifySuccess DSNRcptNotifyOption = "SUCCESS"
// DSNRcptNotifyFailure requests that a DSN be issued on delivery failure
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.1
DSNRcptNotifyFailure DSNRcptNotifyOption = "FAILURE"
// DSNRcptNotifyDelay indicates the sender's willingness to receive
// "delayed" DSNs. Delayed DSNs may be issued if delivery of a message has
// been delayed for an unusual amount of time (as determined by the MTA at
// which the message is delayed), but the final delivery status (whether
// successful or failure) cannot be determined. The absence of the DELAY
// keyword in a NOTIFY parameter requests that a "delayed" DSN NOT be
// issued under any conditions.
// See: https://www.rfc-editor.org/rfc/rfc1891#section-5.1
DSNRcptNotifyDelay DSNRcptNotifyOption = "DELAY"
)
// Client is the SMTP client struct
type Client struct {
// co is the net.Conn that the smtp.Client is based on
co net.Conn
// Timeout for the SMTP server connection
cto time.Duration
// dsn indicates that we want to use DSN for the Client
dsn bool
// dsnmrtype defines the DSNMailReturnOption in case DSN is enabled
dsnmrtype DSNMailReturnOption
// dsnrntype defines the DSNRcptNotifyOption in case DSN is enabled
dsnrntype []string
// enc indicates if a Client connection is encrypted or not
enc bool
// HELO/EHLO string for the greeting the target SMTP server
helo string
// Hostname of the target SMTP server cto connect cto
host string
// pass is the corresponding SMTP AUTH password
pass string
// Port of the SMTP server cto connect cto
port int
// sa is a pointer to smtp.Auth
sa smtp.Auth
// satype represents the authentication type for SMTP AUTH
satype SMTPAuthType
// sc is the smtp.Client that is set up when using the Dial*() methods
sc *smtp.Client
// Use SSL for the connection
ssl bool
@ -50,32 +125,8 @@ type Client struct {
// tlsconfig represents the tls.Config setting for the STARTTLS connection
tlsconfig *tls.Config
// Timeout for the SMTP server connection
cto time.Duration
// HELO/EHLO string for the greeting the target SMTP server
helo string
// enc indicates if a Client connection is encrypted or not
enc bool
// user is the SMTP AUTH username
user string
// pass is the corresponding SMTP AUTH password
pass string
// satype represents the authentication type for SMTP AUTH
satype SMTPAuthType
// co is the net.Conn that the smtp.Client is based on
co net.Conn
// sa is a pointer to smtp.Auth
sa smtp.Auth
// sc is the smtp.Client that is set up when using the Dial*() methods
sc *smtp.Client
}
// Option returns a function that can be used for grouping Client options
@ -107,6 +158,20 @@ var (
// ErrServerNoUnencoded should be used when 8BIT encoding is selected for a message, but
// the server does not offer 8BITMIME mode
ErrServerNoUnencoded = errors.New("message is 8bit unencoded, but server does not support 8BITMIME")
// ErrInvalidDSNMailReturnOption should be used when an invalid option is provided for the
// DSNMailReturnOption in WithDSN
ErrInvalidDSNMailReturnOption = errors.New("DSN mail return option can only be HDRS or FULL")
// ErrInvalidDSNRcptNotifyOption should be used when an invalid option is provided for the
// DSNRcptNotifyOption in WithDSN
ErrInvalidDSNRcptNotifyOption = errors.New("DSN rcpt notify option can only be: NEVER, " +
"SUCCESS, FAILURE or DELAY")
// ErrInvalidDSNRcptNotifyCombination should be used when an invalid option is provided for the
// DSNRcptNotifyOption in WithDSN
ErrInvalidDSNRcptNotifyCombination = errors.New("DSN rcpt notify option NEVER cannot be " +
"combined with any of SUCCESS, FAILURE or DELAY")
)
// NewClient returns a new Session client object
@ -234,6 +299,72 @@ func WithPassword(p string) Option {
}
}
// WithDSN enables the Client to request DSNs (if the server supports it)
// as described in the RFC 1891 and set defaults for DSNMailReturnOption
// to DSNMailReturnFull and DSNRcptNotifyOption to DSNRcptNotifySuccess
// and DSNRcptNotifyFailure
func WithDSN() Option {
return func(c *Client) error {
c.dsn = true
c.dsnmrtype = DSNMailReturnFull
c.dsnrntype = []string{string(DSNRcptNotifyFailure), string(DSNRcptNotifySuccess)}
return nil
}
}
// WithDSNMailReturnType enables the Client to request DSNs (if the server supports it)
// as described in the RFC 1891 and set the MAIL FROM Return option type to the
// given DSNMailReturnOption
// See: https://www.rfc-editor.org/rfc/rfc1891
func WithDSNMailReturnType(mro DSNMailReturnOption) Option {
return func(c *Client) error {
switch mro {
case DSNMailReturnHeadersOnly:
case DSNMailReturnFull:
default:
return ErrInvalidDSNMailReturnOption
}
c.dsn = true
c.dsnmrtype = mro
return nil
}
}
// WithDSNRcptNotifyType enables the Client to request DSNs as described in the RFC 1891
// and sets the RCPT TO notify options to the given list of DSNRcptNotifyOption
// See: https://www.rfc-editor.org/rfc/rfc1891
func WithDSNRcptNotifyType(rno ...DSNRcptNotifyOption) Option {
return func(c *Client) error {
var rnol []string
var ns, nns bool
if len(rno) > 0 {
for _, crno := range rno {
switch crno {
case DSNRcptNotifyNever:
ns = true
case DSNRcptNotifySuccess:
nns = true
case DSNRcptNotifyFailure:
nns = true
case DSNRcptNotifyDelay:
nns = true
default:
return ErrInvalidDSNRcptNotifyOption
}
rnol = append(rnol, string(crno))
}
}
if ns && nns {
return ErrInvalidDSNRcptNotifyCombination
}
c.dsn = true
c.dsnrntype = rnol
return nil
}
}
// TLSPolicy returns the currently set TLSPolicy as string
func (c *Client) TLSPolicy() string {
return c.tlspolicy.String()
@ -351,11 +482,11 @@ func (c *Client) Send(ml ...*Msg) error {
return err
}
if err := c.sc.Mail(f); err != nil {
if err := c.mail(f); err != nil {
return fmt.Errorf("sending MAIL FROM command failed: %w", err)
}
for _, r := range rl {
if err := c.sc.Rcpt(r); err != nil {
if err := c.rcpt(r); err != nil {
return fmt.Errorf("sending RCPT TO command failed: %w", err)
}
}
@ -507,3 +638,91 @@ func (c *Client) auth() error {
}
return nil
}
// mail is an extension to the Go std library mail method. It decideds wether to call the
// original mail method from the std library or in case DSN is enabled on the Client to
// call our own method instead
func (c *Client) mail(f string) error {
ok, _ := c.sc.Extension("DSN")
if ok && c.dsn {
return c.dsnMail(f)
}
return c.sc.Mail(f)
}
// rcpt is an extension to the Go std library rcpt method. It decideds wether to call
// original rcpt method from the std library or in case DSN is enabled on the Client to
// call our own method instead
func (c *Client) rcpt(t string) error {
ok, _ := c.sc.Extension("DSN")
if ok && c.dsn {
return c.dsnRcpt(t)
}
return c.sc.Rcpt(t)
}
// dsnRcpt 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.
//
// This is a copy of the original Go std library net/smtp function with additions
// for the DSN extension
func (c *Client) dsnRcpt(t string) error {
if err := validateLine(t); err != nil {
return err
}
if len(c.dsnrntype) <= 0 {
return c.sc.Rcpt(t)
}
rno := strings.Join(c.dsnrntype, ",")
_, _, err := c.cmd(25, "RCPT TO:<%s> NOTIFY=%s", t, rno)
return err
}
// dsnMail 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. If the server supports the SMTPUTF8 extension, mail adds the
// SMTPUTF8 parameter.
// This initiates a mail transaction and is followed by one or more rcpt calls.
//
// This is a copy of the original Go std library net/smtp function with additions
// for the DSN extension
func (c *Client) dsnMail(f string) error {
if err := validateLine(f); err != nil {
return err
}
cmdStr := "MAIL FROM:<%s>"
if ok, _ := c.sc.Extension("8BITMIME"); ok {
cmdStr += " BODY=8BITMIME"
}
if ok, _ := c.sc.Extension("SMTPUTF8"); ok {
cmdStr += " SMTPUTF8"
}
cmdStr += fmt.Sprintf(" RET=%s", c.dsnmrtype)
_, _, err := c.cmd(250, cmdStr, f)
return err
}
// validateLine checks to see if a line has CR or LF as per RFC 5321
// This is a 1:1 copy of the method from the original Go std library net/smtp
func validateLine(line string) error {
if strings.ContainsAny(line, "\n\r") {
return errors.New("smtp: A line must not contain CR or LF")
}
return nil
}
// cmd is a convenience function that sends a command and returns the response
// This is a 1:1 copy of the method from the original Go std library net/smtp
func (c *Client) cmd(expectCode int, format string, args ...interface{}) (int, string, error) {
id, err := c.sc.Text.Cmd(format, args...)
if err != nil {
return 0, "", err
}
c.sc.Text.StartResponse(id)
defer c.sc.Text.EndResponse(id)
code, msg, err := c.sc.Text.ReadResponse(expectCode)
return code, msg, err
}

231
client_test.go
View file

@ -94,6 +94,13 @@ func TestNewClientWithOptions(t *testing.T) {
false},
{"WithUsername()", WithUsername("test"), false},
{"WithPassword()", WithPassword("test"), false},
{"WithDSN()", WithDSN(), false},
{"WithDSNMailReturnType()", WithDSNMailReturnType(DSNMailReturnFull), false},
{"WithDSNMailReturnType() wrong option", WithDSNMailReturnType("FAIL"), true},
{"WithDSNRcptNotifyType()", WithDSNRcptNotifyType(DSNRcptNotifySuccess), false},
{"WithDSNRcptNotifyType() wrong option", WithDSNRcptNotifyType("FAIL"), true},
{"WithDSNRcptNotifyType() NEVER combination",
WithDSNRcptNotifyType(DSNRcptNotifySuccess, DSNRcptNotifyNever), true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
@ -367,6 +374,87 @@ func TestSetSMTPAuth(t *testing.T) {
}
}
// TestWithDSN tests the WithDSN method for the Client object
func TestWithDSN(t *testing.T) {
c, err := NewClient(DefaultHost, WithDSN())
if err != nil {
t.Errorf("failed to create new client: %s", err)
return
}
if !c.dsn {
t.Errorf("WithDSN failed. c.dsn expected to be: %t, got: %t", true, c.dsn)
}
if c.dsnmrtype != DSNMailReturnFull {
t.Errorf("WithDSN failed. c.dsnmrtype expected to be: %s, got: %s", DSNMailReturnFull,
c.dsnmrtype)
}
if c.dsnrntype[0] != string(DSNRcptNotifyFailure) {
t.Errorf("WithDSN failed. c.dsnrntype[0] expected to be: %s, got: %s", DSNRcptNotifyFailure,
c.dsnrntype[0])
}
if c.dsnrntype[1] != string(DSNRcptNotifySuccess) {
t.Errorf("WithDSN failed. c.dsnrntype[1] expected to be: %s, got: %s", DSNRcptNotifySuccess,
c.dsnrntype[1])
}
}
// TestWithDSNMailReturnType tests the WithDSNMailReturnType method for the Client object
func TestWithDSNMailReturnType(t *testing.T) {
tests := []struct {
name string
value DSNMailReturnOption
want string
sf bool
}{
{"WithDSNMailReturnType: FULL", DSNMailReturnFull, "FULL", false},
{"WithDSNMailReturnType: HDRS", DSNMailReturnHeadersOnly, "HDRS", false},
{"WithDSNMailReturnType: INVALID", "INVALID", "", true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
c, err := NewClient(DefaultHost, WithDSNMailReturnType(tt.value))
if err != nil && !tt.sf {
t.Errorf("failed to create new client: %s", err)
return
}
if string(c.dsnmrtype) != tt.want {
t.Errorf("WithDSNMailReturnType failed. Expected %s, got: %s", tt.want, string(c.dsnmrtype))
}
})
}
}
// TestWithDSNRcptNotifyType tests the WithDSNRcptNotifyType method for the Client object
func TestWithDSNRcptNotifyType(t *testing.T) {
tests := []struct {
name string
value DSNRcptNotifyOption
want string
sf bool
}{
{"WithDSNRcptNotifyType: NEVER", DSNRcptNotifyNever, "NEVER", false},
{"WithDSNRcptNotifyType: SUCCESS", DSNRcptNotifySuccess, "SUCCESS", false},
{"WithDSNRcptNotifyType: FAILURE", DSNRcptNotifyFailure, "FAILURE", false},
{"WithDSNRcptNotifyType: DELAY", DSNRcptNotifyDelay, "DELAY", false},
{"WithDSNRcptNotifyType: INVALID", "INVALID", "", true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
c, err := NewClient(DefaultHost, WithDSNRcptNotifyType(tt.value))
if err != nil && !tt.sf {
t.Errorf("failed to create new client: %s", err)
return
}
if len(c.dsnrntype) <= 0 && !tt.sf {
t.Errorf("WithDSNRcptNotifyType failed. Expected at least one DSNRNType but got none")
}
if !tt.sf && c.dsnrntype[0] != tt.want {
t.Errorf("WithDSNRcptNotifyType failed. Expected %s, got: %s", tt.want, c.dsnrntype[0])
}
})
}
}
// TestSetSMTPAuthCustom tests the SetSMTPAuthCustom method for the Client object
func TestSetSMTPAuthCustom(t *testing.T) {
tests := []struct {
@ -589,6 +677,30 @@ func TestClient_DialAndSend(t *testing.T) {
}
}
// TestClient_DialAndSendWithDSN tests the DialAndSend() method of Client with DSN enabled
func TestClient_DialAndSendWithDSN(t *testing.T) {
if os.Getenv("TEST_ALLOW_SEND") == "" {
t.Skipf("TEST_ALLOW_SEND is not set. Skipping mail sending test")
}
m := NewMsg()
_ = m.FromFormat("go-mail Test Mailer", os.Getenv("TEST_FROM"))
_ = m.To(TestRcpt)
m.Subject(fmt.Sprintf("This is a test mail from go-mail/v%s", VERSION))
m.SetBulk()
m.SetDate()
m.SetMessageID()
m.SetBodyString(TypeTextPlain, "This is a test mail from the go-mail library")
c, err := getTestConnectionWithDSN(true)
if err != nil {
t.Skipf("failed to create test client: %s. Skipping tests", err)
}
if err := c.DialAndSend(m); err != nil {
t.Errorf("DialAndSend() failed: %s", err)
}
}
// TestClient_DialSendCloseBroken tests the Dial(), Send() and Close() method of Client with broken settings
func TestClient_DialSendCloseBroken(t *testing.T) {
if os.Getenv("TEST_ALLOW_SEND") == "" {
@ -649,6 +761,67 @@ func TestClient_DialSendCloseBroken(t *testing.T) {
}
// TestClient_DialSendCloseBrokenWithDSN tests the Dial(), Send() and Close() method of Client with
// broken settings and DSN enabled
func TestClient_DialSendCloseBrokenWithDSN(t *testing.T) {
if os.Getenv("TEST_ALLOW_SEND") == "" {
t.Skipf("TEST_ALLOW_SEND is not set. Skipping mail sending test")
}
tests := []struct {
name string
from string
to string
closestart bool
closeearly bool
sf bool
}{
{"Invalid FROM", "foo@foo", TestRcpt, false, false, true},
{"Invalid TO", os.Getenv("TEST_FROM"), "foo@foo", false, false, true},
{"No FROM", "", TestRcpt, false, false, true},
{"No TO", os.Getenv("TEST_FROM"), "", false, false, true},
{"Close early", os.Getenv("TEST_FROM"), TestRcpt, false, true, true},
{"Close start", os.Getenv("TEST_FROM"), TestRcpt, true, false, true},
{"Close start/early", os.Getenv("TEST_FROM"), TestRcpt, true, true, true},
}
m := NewMsg(WithEncoding(NoEncoding))
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
m.SetAddrHeaderIgnoreInvalid(HeaderFrom, tt.from)
m.SetAddrHeaderIgnoreInvalid(HeaderTo, tt.to)
c, err := getTestConnectionWithDSN(true)
if err != nil {
t.Skipf("failed to create test client: %s. Skipping tests", err)
}
ctx, cfn := context.WithTimeout(context.Background(), time.Second*10)
defer cfn()
if err := c.DialWithContext(ctx); err != nil && !tt.sf {
t.Errorf("Dail() failed: %s", err)
return
}
if tt.closestart {
_ = c.sc.Close()
_ = c.co.Close()
}
if err := c.Send(m); err != nil && !tt.sf {
t.Errorf("Send() failed: %s", err)
return
}
if tt.closeearly {
_ = c.sc.Close()
_ = c.co.Close()
}
if err := c.Close(); err != nil && !tt.sf {
t.Errorf("Close() failed: %s", err)
return
}
})
}
}
// TestClient_auth tests the Dial(), Send() and Close() method of Client with broken settings
func TestClient_auth(t *testing.T) {
tests := []struct {
@ -687,6 +860,27 @@ func TestClient_auth(t *testing.T) {
}
}
// TestValidateLine tests the validateLine() method
func TestValidateLine(t *testing.T) {
tests := []struct {
name string
value string
sf bool
}{
{"valid line", "valid line", false},
{`invalid line: \n`, "invalid line\n", true},
{`invalid line: \r`, "invalid line\r", true},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if err := validateLine(tt.value); err != nil && !tt.sf {
t.Errorf("validateLine failed: %s", err)
}
})
}
}
// getTestConnection takes environment variables to establish a connection to a real
// SMTP server to test all functionality that requires a connection
func getTestConnection(auth bool) (*Client, error) {
@ -723,3 +917,40 @@ func getTestConnection(auth bool) (*Client, error) {
}
return c, nil
}
// getTestConnectionWithDSN takes environment variables to establish a connection to a real
// SMTP server to test all functionality that requires a connection. It also enables DSN
func getTestConnectionWithDSN(auth bool) (*Client, error) {
if os.Getenv("TEST_SKIP_ONLINE") != "" {
return nil, fmt.Errorf("env variable TEST_SKIP_ONLINE is set. Skipping online tests")
}
th := os.Getenv("TEST_HOST")
if th == "" {
return nil, fmt.Errorf("no TEST_HOST set")
}
c, err := NewClient(th, WithDSN())
if err != nil {
return c, err
}
if auth {
st := os.Getenv("TEST_SMTPAUTH_TYPE")
if st != "" {
c.SetSMTPAuth(SMTPAuthType(st))
}
u := os.Getenv("TEST_SMTPAUTH_USER")
if u != "" {
c.SetUsername(u)
}
p := os.Getenv("TEST_SMTPAUTH_PASS")
if p != "" {
c.SetPassword(p)
}
}
if err := c.DialWithContext(context.Background()); err != nil {
return c, fmt.Errorf("connection to test server failed: %s", err)
}
if err := c.Close(); err != nil {
return c, fmt.Errorf("disconnect from test server failed: %s", err)
}
return c, nil
}