readme updates

Author: wiggin77

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 wiggin77
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,43 @@
+# mailrelay
+
+`mailrelay` is a simple mail relay that can take unauthenticated SMTP emails (e.g. over port 25) and relay them to authenticated, TLS-enabled SMTP servers. Plus it's easy to configure.
+
+## Use case
+
+Some older appliances such as scanners, multi-function printers, RAID cards or NAS boxes with monitoring, can only send email without any authentication or encryption over port 25. `mailrelay` can send those emails to your Gmail, Fastmail or other provider.
+
+Run `mailrelay` on a local PC and set your device (e.g. scanner) to send mail to that PC.
+
+`mailrelay` is written in Go, and can be compiled for any Go supported platform including Linux, MacOS, Windows.
+
+## Example (Linux)
+
+On local PC (192.168.1.54) create file `/etc/mailrelay.json` with contents:
+
+/etc/mailrelay.json
+
+```json
+{
+    "smtp_server":   "smtp.fastmail.com",
+    "smtp_port":     465,
+    "smtp_username": "[email protected]",
+    "smtp_password": "secretAppPassword",
+    "local_listen_ip": "0.0.0.0",
+    "local_listen_port": 2525
+}
+```
+
+Run `mailrelay`,
+
+```Bash
+./mailrelay
+```
+
+Default location for configuration file is `/etc/mailrelay.json` but can be changed via `--config` flag. For example,
+
+```bash
+mailrelay --config=/home/myname/mailrelay.json
+```
+
+Configure your scanner or other device to send SMTP mail to server `192.168.1.54:2525`. Each email will be relayed to `smtp.fastmail.com` using the credentials above, including any file attachments.
+

client.go

@@ -17,8 +17,8 @@ type closeable interface {
 }
 
 // sendMail sends the contents of the envelope to a SMTP server.
-func sendMail(e *mail.Envelope, config *mailRelayConfig) error {
-	server := fmt.Sprintf("%s:%d", config.Server, config.Port)
+func sendMail(e *mail.Envelope, config *relayConfig) error {
+	server := fmt.Sprintf("%s:%d", config.SMTPServer, config.SMTPPort)
 	to := getTo(e)
 
 	var msg bytes.Buffer
@@ -34,14 +34,14 @@ func sendMail(e *mail.Envelope, config *mailRelayConfig) error {
 
 	tlsconfig := &tls.Config{
 		InsecureSkipVerify: true,
-		ServerName:         config.Server,
+		ServerName:         config.SMTPServer,
 	}
 
 	if conn, err = tls.Dial("tcp", server, tlsconfig); err != nil {
 		return errors.Wrap(err, "dial error")
 	}
 
-	if client, err = smtp.NewClient(conn, config.Server); err != nil {
+	if client, err = smtp.NewClient(conn, config.SMTPServer); err != nil {
 		close(conn, "conn")
 		return errors.Wrap(err, "newclient error")
 	}
@@ -52,7 +52,7 @@ func sendMail(e *mail.Envelope, config *mailRelayConfig) error {
 		}
 	}(&shouldCloseClient)
 
-	auth := smtp.PlainAuth("", config.Username, config.Password, config.Server)
+	auth := smtp.PlainAuth("", config.SMTPUsername, config.SMTPPassword, config.SMTPServer)
 	if err = client.Auth(auth); err != nil {
 		return errors.Wrap(err, "auth error")
 	}

mailrelay.json

@@ -0,0 +1,8 @@
+{
+	"smtp_server": "smtp.fastmail.com",
+	"smtp_port": 465,
+	"smtp_username": "[email protected]",
+	"smtp_password": "secret_app_password",
+	"local_listen_port": "0.0.0.0",
+	"local_listen_ip": 2525
+}

main.go

@@ -15,10 +15,12 @@ type loggerLevels struct {
 }
 
 type mailRelayConfig struct {
-	Server   string `json:"server"`
-	Port     int    `json:"port"`
-	Username string `json:"username"`
-	Password string `json:"password"`
+	SMTPServer      string `json:"smtp_server"`
+	SMTPPort        int    `json:"smtp_port"`
+	SMTPUsername    string `json:"smtp_username"`
+	SMTPPassword    string `json:"smtp_password"`
+	LocalListenIP   string `json:"local_listen_ip"`
+	LocalListenPort int    `json:"local_listen_port"`
 }
 
 // Logger provides application logging.

server.go

@@ -12,9 +12,11 @@ import (
 // Start starts the server.
 func Start(appConfig *mailRelayConfig) (err error) {
 
+	listen := fmt.Sprintf("%s:%d", appConfig.LocalListenIP, appConfig.LocalListenPort)
+
 	cfg := &guerrilla.AppConfig{LogFile: log.OutputStdout.String(), AllowedHosts: []string{"warpmail.net"}}
 	sc := guerrilla.ServerConfig{
-		ListenInterface: "0.0.0.0:2525",
+		ListenInterface: listen,
 		IsEnabled:       true,
 	}
 	cfg.Servers = append(cfg.Servers, sc)
@@ -24,10 +26,10 @@ func Start(appConfig *mailRelayConfig) (err error) {
 		"save_process":       "HeadersParser|Header|Hasher|Debugger|MailRelay",
 		"log_received_mails": true,
 		"primary_mail_host":  "homeoffice.com",
-		"username":           appConfig.Username,
-		"password":           appConfig.Password,
-		"server":             appConfig.Server,
-		"port":               appConfig.Port,
+		"smtp_username":      appConfig.SMTPUsername,
+		"smtp_password":      appConfig.SMTPPassword,
+		"smtp_server":        appConfig.SMTPServer,
+		"smtp_port":          appConfig.SMTPPort,
 	}
 	cfg.BackendConfig = bcfg
 
@@ -37,16 +39,23 @@ func Start(appConfig *mailRelayConfig) (err error) {
 	return d.Start()
 }
 
+type relayConfig struct {
+	SMTPServer   string `json:"smtp_server"`
+	SMTPPort     int    `json:"smtp_port"`
+	SMTPUsername string `json:"smtp_username"`
+	SMTPPassword string `json:"smtp_password"`
+}
+
 // mailRelayProcessor decorator relays emails to another SMTP server.
 var mailRelayProcessor = func() backends.Decorator {
-	config := &mailRelayConfig{}
+	config := &relayConfig{}
 	initFunc := backends.InitializeWith(func(backendConfig backends.BackendConfig) error {
-		configType := backends.BaseConfig(&mailRelayConfig{})
+		configType := backends.BaseConfig(&relayConfig{})
 		bcfg, err := backends.Svc.ExtractConfig(backendConfig, configType)
 		if err != nil {
 			return err
 		}
-		config = bcfg.(*mailRelayConfig)
+		config = bcfg.(*relayConfig)
 		return nil
 	})
 	backends.Svc.AddInitializer(initFunc)