From 3e52620c29e6893ce1cf5e45ec4e00a37184edd6 Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Wed, 28 Aug 2013 15:53:04 +0200
Subject: Added mailing interface (from other project)

---
 mailing/mailer.go          | 13 +++++++++
 mailing/mailers.go         |  5 ++++
 mailing/sendmail_mailer.go | 73 ++++++++++++++++++++++++++++++++++++++++++++++
 mailing/smtp_mailer.go     | 60 +++++++++++++++++++++++++++++++++++++
 4 files changed, 151 insertions(+)
 create mode 100644 mailing/mailer.go
 create mode 100644 mailing/mailers.go
 create mode 100644 mailing/sendmail_mailer.go
 create mode 100644 mailing/smtp_mailer.go

diff --git a/mailing/mailer.go b/mailing/mailer.go
new file mode 100644
index 0000000..c9ab8d0
--- /dev/null
+++ b/mailing/mailer.go
@@ -0,0 +1,13 @@
+package mailing
+
+import (
+	"github.com/kch42/simpleconf"
+)
+
+// Mailer is a interface that defines the Mail function.
+type Mailer interface {
+	Mail(to, from string, msg []byte) error
+}
+
+// MailerCreator is a function that creates a Mailer instance from config values.
+type MailerCreator func(conf simpleconf.Config) (Mailer, error)
diff --git a/mailing/mailers.go b/mailing/mailers.go
new file mode 100644
index 0000000..7f550c5
--- /dev/null
+++ b/mailing/mailers.go
@@ -0,0 +1,5 @@
+package mailing
+
+var MailersByName = map[string]MailerCreator{
+	"smtp":     SMTPMailerCreator,
+	"sendmail": SendmailMailerCreator}
diff --git a/mailing/sendmail_mailer.go b/mailing/sendmail_mailer.go
new file mode 100644
index 0000000..ad864fb
--- /dev/null
+++ b/mailing/sendmail_mailer.go
@@ -0,0 +1,73 @@
+package mailing
+
+import (
+	"errors"
+	"fmt"
+	"github.com/kch42/simpleconf"
+	"os/exec"
+)
+
+// SendmailMailer is a Mailer implementation that sends mail using a sendmail-ish executable.
+//
+// Sendmail-ish in this context means:
+//
+// 	* The executable must accept the from address using the `-f <addr>` switch
+// 	* The executable must accept the to address as a parameter
+// 	* The executable expects a mail (including all headers) on stdin that is terminated by EOF
+type SendmailMailer struct {
+	Exec string
+	Args []string
+}
+
+func (sm SendmailMailer) Mail(to, from string, msg []byte) (outerr error) {
+	off := len(sm.Args)
+	args := make([]string, off+3)
+	copy(args, sm.Args)
+	args[off] = "-f"
+	args[off+1] = from
+	args[off+2] = to
+
+	cmd := exec.Command(sm.Exec, args...)
+	pipe, err := cmd.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	if err = cmd.Start(); err != nil {
+		return err
+	}
+	defer func() {
+		pipe.Close()
+		err := cmd.Wait()
+		if outerr == nil {
+			outerr = err
+		}
+	}()
+
+	_, err = pipe.Write(msg)
+	return err
+}
+
+// SendmailMailerCreator creates an SendmailMailer using configuration values in the [mail] section.
+//
+// 	exec - The name of the executable
+// 	argX - (optional) Additional arguments for the executable. X is a ascending number starting with 1
+func SendmailMailerCreator(conf simpleconf.Config) (Mailer, error) {
+	rv := SendmailMailer{}
+	var err error
+
+	if rv.Exec, err = conf.GetString("mail", "exec"); err != nil {
+		return rv, errors.New("Missing [mail] exec config")
+	}
+
+	for i := 1; ; i++ {
+		arg, err := conf.GetString("mail", fmt.Sprintf("arg%d", i))
+		if err != nil {
+			break
+		}
+
+		rv.Args = append(rv.Args, arg)
+	}
+
+	return rv, nil
+}
diff --git a/mailing/smtp_mailer.go b/mailing/smtp_mailer.go
new file mode 100644
index 0000000..2a90173
--- /dev/null
+++ b/mailing/smtp_mailer.go
@@ -0,0 +1,60 @@
+package mailing
+
+import (
+	"errors"
+	"github.com/kch42/simpleconf"
+	"net/smtp"
+)
+
+// SMTPMailer is a Mailer implementation that sends mail via an smtp server.
+type SMTPMailer struct {
+	Host       string // Host is the expected hostname of the server
+	Addr       string // Addr is the address of the server
+	UseCRAMMD5 bool
+	Username   string
+	Password   string
+}
+
+func (sm SMTPMailer) Mail(to, from string, msg []byte) error {
+	var auth smtp.Auth
+	if sm.UseCRAMMD5 {
+		auth = smtp.CRAMMD5Auth(sm.Username, sm.Password)
+	} else {
+		auth = smtp.PlainAuth("", sm.Username, sm.Password, sm.Host)
+	}
+
+	return smtp.SendMail(sm.Addr, auth, from, []string{to}, msg)
+}
+
+// SMTPMailerCreator creates an SMTPMailer using configuration values in the [mail] section.
+//
+// 	addr    - The address of the smtp server (go notation)
+// 	user    - Username
+// 	passwd  - Password
+// 	crammd5 - Should CRAMMD5 (on) or PLAIN (off) be used?
+// 	host    - The expected hostname of the mailserver (can be left out, if crammd5 is on)
+//
+func SMTPMailerCreator(conf simpleconf.Config) (Mailer, error) {
+	rv := SMTPMailer{}
+	var err error
+
+	if rv.Addr, err = conf.GetString("mail", "addr"); err != nil {
+		return rv, errors.New("Missing [mail] addr config")
+	}
+	if rv.UseCRAMMD5, err = conf.GetBool("mail", "crammd5"); err != nil {
+		return rv, errors.New("Missing [mail] crammd5 config")
+	}
+	if rv.Username, err = conf.GetString("mail", "user"); err != nil {
+		return rv, errors.New("Missing [mail] user config")
+	}
+	if rv.Password, err = conf.GetString("mail", "passwd"); err != nil {
+		return rv, errors.New("Missing [mail] passwd config")
+	}
+	if !rv.UseCRAMMD5 {
+		if rv.Host, err = conf.GetString("mail", "host"); err != nil {
+			return rv, errors.New("Missing [mail] host config")
+		}
+	}
+
+	return rv, nil
+}
-- 
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