Sending E-mail and reading a config for that

.gitignore

@@ -0,0 +1 @@
+secret-data.config.json

email.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"github.com/go-mail/mail"
+)
+
+func playWithEmail() {
+   scd := &SecretConfigData
+	m := mail.NewMessage()
+	m.SetHeader("From", scd.SenderEMail)
+	m.SetHeader("To", scd.RecieverEMail)
+	m.SetHeader("Subject", "Hello!")
+	m.SetBody("text/html", "Hello world!")
+
+	d := mail.NewDialer(scd.SMTPServer, 587, scd.SMTPUser, scd.SMTPPassword)
+
+	if err := d.DialAndSend(m); err != nil {
+		fmt.Printf("Failed to send an E-mail, err = %#v\n", err)
+	}
+}

main.go

@@ -11,11 +11,20 @@ package main
 import (
 	"fmt" )
 
+const ActuallySendEmailP = false
+
 func main() {
 	playWithDb()
 	playWithPanic()
 	playWithNonce(16)
 	playWithHashAndSalt()
+	/// Uncomment next line to create secret-data.config.json.example
+	//saveSecretConfigDataExample()
+	loadSecretConfigData()
+	if (ActuallySendEmailP) {
+		playWithEmail() 
+	} else { 
+		fmt.Println("Bypassing sending E-mail due to ActuallySendEmailP == false") }
 	return }
 
 

secret-data.config.json.example

@@ -0,0 +1,8 @@
+{
+ "Comment": "Example config file. Copy this one to the secret-data.config.json and edit",
+ "RecieverEMail": "world@example.net",
+ "SMTPServer": "smtp.example.net",
+ "SMTPUser": "Кирилл",
+ "SMTPPassword": "bla-bla-bla",
+ "SenderEMail": "den@example.net"
+}

secret-data.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"strings"
+	"fmt"
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	// "github.com/flynn/json5"
+)
+
+type SecretConfigDataStruct struct {
+	Comment       string
+	RecieverEMail string
+	SMTPServer    string
+	SMTPUser      string
+	SMTPPassword  string
+	SenderEMail   string
+}
+
+var SecretConfigData SecretConfigDataStruct
+
+func (sds *SecretConfigDataStruct) SaveToFile(filename string) (err error) {
+	var text []byte
+	text, err = json.MarshalIndent(sds,""," ")
+	if err != nil {
+		return
+	}
+	err = ioutil.WriteFile(filename, text, 0600)
+	return
+}
+
+const ConfigFileName = "secret-data.config.json"
+
+// for development
+func saveSecretConfigDataExample() {
+	sds := SecretConfigDataStruct{
+		Comment:       "Example config file. Copy this one to the secret-data.config.json and edit",
+		SenderEMail:   "den@example.net",
+		RecieverEMail: "world@example.net",
+		SMTPServer:    "smtp.example.net",
+		SMTPUser:      "Кирилл",
+		SMTPPassword:  "bla-bla-bla"}
+	err := sds.SaveToFile(ConfigFileName + ".example")
+	if err != nil {
+		panic(err)	}}
+
+func loadSecretConfigData() (err error) {
+	sds := &SecretConfigData
+	fn := ConfigFileName
+	if _, err = os.Stat(fn); os.IsNotExist(err) {
+		fmt.Printf("No config file %s found. Create one by copying from %s.example\n",
+			fn, fn)
+		return	}
+	var bytes []byte
+	bytes, err = ioutil.ReadFile(fn)
+	if err != nil {
+		fmt.Printf("Unable to read config %s\n", fn)
+		return	}
+		dec := json.NewDecoder(strings.NewReader(string(bytes)))
+		dec.DisallowUnknownFields() 
+		err = dec.Decode(sds)
+	if err != nil {
+		fmt.Printf("Error reading config file %s: %#v\n", fn, err)
+		return	}
+	fmt.Printf("playWithSecretConfigData returned %#v\n", sds)
+	return }
+