first commit

.env.example

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+JWT_ALGORITHM=<jwt algorithm encrypted>
+JWT_PUBLIC_KEY=<jwt public key not path>
+
+RABBITMQ_URL=<rabbitmq host with format "amqp://{username}:{password}@{host}:{port}/">
+RABBITMQ_QUEUE_NAME=<rabbitmq queue name>
+
+SMTP_HOST={smtp host }
+SMTP_PORT={ smtp port }
+SMTP_USER={ smtp username }
+SMTP_PASS={ smtp password }
+SMTP_SENDER_EMAIL={ smtp sender email }
+SMTP_SENDER_NAME={ smttp sender name }

.gitignore

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+.env

README.md

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+# ======> MAILER SERVICE <========
+golang project provided to handle mailer service and has been integrated with `rabbitmq`, on channel `mailer_queue` and templateing with file `.html`, for provider sending email using smtp2go for the testing with template of `.env` is ready on this project,
+
+the project using `enqueue` concept that set in file `rabbitmq/rabbitmq.go` will be automatically send `message` after consumming message from channel set on file `.env`
+
+for example of list template email to send you can see in file `templates/*_template.html` for the lsit of template that will using message with variable `tag` on the message from channel for list of `tag` you can see at the file `handlers/handlers.go` and here this of list the `tag`
+
+    1. login
+    2. send_code
+    3. reset_password
+    4. api_key
+
+that must be the same name on file `templates/*_template.html`, and if you want to customize the project you can update the file list
+
+    1. handlers -> file to handle tag of message from consuming message from queue
+    2. interfaces -> file to handling interfaces message like all variable they have
+    3. mailes -> file to handling send mail with configuration template from message
+    4. rabbitmq -> file to handling configuration of queue and subcribe to channel has been declared on rabbitmq queue
+    5. templates -> file to handling templating style to show for user
+    6. token -> file to handling decrypted message jwt from queue channel
+
+flow of system on this project just like this :
+
+the flow of system is started from your project
+
+```
+-> publish message json to rabbitmq channel when has been encrypted with jwt private key (example of json you see after this)
+-> mailer service subcribe to channel and consume the message
+-> message will decrypted first to check the tag 
+-> system will generate template of message with using json message after decryption
+-> system will send message to target email
+```
+
+project will using dual decrypted when `first decrypted` is for to get `tag` group that using `Record` interfaces and then project will decrypt again using file in `interfaces` to get list of json messages `when is suitable on tag and handlers`
+
+```
+example of json data
+{
+    record: {
+        email: string, // email address user
+        tag: string, // tag is for description to generate file
+        subject: string // subject of message to subject on email send
+    },
+    iss: 'name_project',
+    iat: <Time on Integer>,
+    exp: <Time on Integer>,
+    jti: SecureRandom.hex(10)
+}
+```
+
+## ======> SETUP <========
+Setup for this project is simple, you must prepare the configuration on file `.env`, configuration channel on the `rabbitmq`, the list of configuration you must following the step :
+
+1. RabbitMQ
+
+configuration rabbitmq you can follow this link `https://www.rabbitmq.com/download.html`
+
+or you want to easly install RabbitMQ configuration you can running command on your terminal using
+
+```bash
+$ cd config && docker-compose up -Vd
+```
+after your config for rabbitmq installation don't forget to update sthe file `.env` on variable `RABBITMQ_HOST` with host to your `rabbitmq` has `installed`
+
+2. Channel configuration
+
+Channel configration you can using file in `config/rabbitmq_channel.yaml` on your project because this project just for consuming from config channel when you set in rabbitmq
+you can create channel in rabbitmq in `exchange` and `queue` and don't forget to set the `queue_name` when you has been config in file `.env`
+
+3. SMTP
+
+Mailer using `github.com/go-mail/mail` for the package and for the configuration you can set in file `.env` on list variable in below
+```
+SMTP_HOST={smtp host }
+SMTP_PORT={ smtp port }
+SMTP_USER={ smtp username }
+SMTP_PASS={ smtp password }
+SMTP_SENDER_EMAIL={ smtp sender email }
+SMTP_SENDER_NAME={ smttp sender name }
+```
+don't forget to change that `smtp configuration` with your smtp mailer you have, but on `sender email` must using `activated email` like `[email protected]` or something else, if you want to customize that configuration you can change in file `mailers/mailers.go`
+
+4. JWT
+
+configuration jwt is easy, you just need to `generate` the `jwt_public_key` and `jwt_private_key` and set the `algorithm` on file `.env`, you can follow the step :
+
+- Generate Private Key
+```bash
+$ openssl genpkey -algorithm RSA -out private_key.pem
+```
+
+- Generate Public Key
+```bash
+$ openssl rsa -in private_key.pem -pubout -out public_key.pem
+```
+
+but in this project you must to convert that file output to `base64` configuration `private_key` or `public_key`
+- Convert private key to base64
+```bash
+$ openssl base64 -in private_key.pem
+```
+- Convert Public key to base64
+```bash
+$ openssl rsa -in private_key.pem -pubout -outform DER | openssl base64 -A
+```
+
+after that you can set that `private_key` on your project to protect the message from your project for executing on this `mailer-service`, and for `mailer-service` you can must to using that `public_key` to decrypted the message from your `project` after consuming channel has you declared in file `.env`

config/docker-compose.yml

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+version: '3.6'
+  rabbitmq:
+      image: rabbitmq:3.7.6-management
+      restart: always
+      ports:
+        - "5672:5672"
+        - "15672:15672"
+      volumes:
+        - rabbitmq_data:/var/lib/rabbitmq
+      logging:
+        driver: "json-file"
+        options:
+            max-size: "50m"
+
+volumes:
+  rabbitmq_data:

config/rabbitmq_channel.yml

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+exchanges:
+  - name: mailer_exchange
+    type: direct
+    durable: false
+    auto_delete: false
+queues:
+  - name: mailer_queue
+    durable: true
+    auto_delete: false
+    bindings:
+      - exchange: mailer_exchange
+        routing_key: mailer.send_email

go.mod

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+module mailer
+
+go 1.16
+
+require (
+	github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
+	github.com/go-mail/mail v2.3.1+incompatible // indirect
+	github.com/joho/godotenv v1.5.1 // indirect
+	github.com/streadway/amqp v1.1.0 // indirect
+	gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect
+)

go.sum

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+github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
+github.com/go-mail/mail v2.3.1+incompatible h1:UzNOn0k5lpfVtO31cK3hn6I4VEVGhe3lX8AJBAxXExM=
+github.com/go-mail/mail v2.3.1+incompatible/go.mod h1:VPWjmmNyRsWXQZHVHT3g0YbIINUkSmuKOiLIDkWbL6M=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/streadway/amqp v1.1.0 h1:py12iX8XSyI7aN/3dUT8DFIDJazNJsVJdxNVEpnQTZM=
+github.com/streadway/amqp v1.1.0/go.mod h1:WYSrTEYHOXHd0nwFeUXAe2G2hRnQT+deZJJf88uS9Bg=
+gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc h1:2gGKlE2+asNV9m7xrywl36YYNnBG5ZQ0r/BOOxqPpmk=
+gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc/go.mod h1:m7x9LTH6d71AHyAX77c9yqWCCa3UKHcVEj9y7hAtKDk=

handlers/handlers.go

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+package handlers
+
+import (
+	"log"
+
+	"mailer/token"
+	"mailer/interfaces"
+)
+
+func ClaimAllRecordData(msg string, tag string) (interface{}, error) {
+	switch tag {
+		case "login":
+			var interfaceData interfaces.Login
+			record := token.DecodeToken(msg, &interfaceData)
+			if record != nil {
+				log.Println(record)
+				return nil, record
+			}
+
+			return interfaceData, nil
+		case "send_code":
+			var interfaceData interfaces.VerifToken
+			record := token.DecodeToken(msg, &interfaceData)
+			if record != nil {
+				log.Println(record)
+				return nil, record
+			}
+
+			return interfaceData, nil
+		case "reset_password":
+			var interfaceData interfaces.VerifToken
+			record := token.DecodeToken(msg, &interfaceData)
+			if record != nil {
+				log.Println(record)
+				return nil, record
+			}
+
+			return interfaceData, nil
+		case "api_key":
+			var interfaceData interfaces.APIKey
+			record := token.DecodeToken(msg, &interfaceData)
+			if record != nil {
+				log.Println(record)
+				return nil, record
+			}
+
+			return interfaceData, nil
+		default:
+			log.Println("Tag not recognized")
+
+			var interfaceData interfaces.Record
+			return interfaceData, nil
+	}
+}

interfaces/api_key.go

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+package interfaces
+
+type APIKey struct {
+	Label			string	`json:"label"`
+	ApiKey			string	`json:"api_key"`
+	ActivationToken	int		`json:"activation_token"`
+}

interfaces/login.go

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+package interfaces
+
+type Login struct {
+	Email           string  `json:"email"`
+	Device			string	`json:"device,omitempty"`
+	LoginTime		string	`json:"login_time,omitempty"`
+}

interfaces/record.go

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+package interfaces
+
+type Record struct {
+	Subject			string  `json:"subject"`
+	Tag				string	`json:"tag"`
+	Email			string	`json:"email"`
+}

interfaces/verif_token.go

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+package interfaces
+
+type VerifToken struct {
+	Username					string 		`json:"username"`
+	Email           			string  	`json:"email"`
+	GoogleID					string 		`json:"google_id"`
+	Role						string		`json:"role"`
+	ActivationCode				int 		`json:"email_verification_token"`
+	ResetPasswordToken			int			`json:"reset_password_token"`
+}

mailers/mailers.go

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+package mailers
+
+import (
+	"os"
+	"log"
+	"bytes"
+	"strconv"
+	"text/template"
+	"mailer/interfaces"
+
+	"github.com/go-mail/mail"
+	"github.com/joho/godotenv"
+)
+
+func SendMail(record interfaces.Record, msg interface{}){
+	err := godotenv.Load()
+	if err != nil {
+		log.Println("Error loading .env file:", err)
+	}
+
+	smtpHost := os.Getenv("SMTP_HOST")
+	smtpPortStr := os.Getenv("SMTP_PORT")
+	smtpUser := os.Getenv("SMTP_USER")
+	smtpPass := os.Getenv("SMTP_PASS")
+	senderEmail := os.Getenv("SMTP_SENDER_EMAIL")
+	senderName := os.Getenv("SMTP_SENDER_NAME")
+
+	templateName := record.Tag+"_template.html"
+
+	var tmpl *template.Template
+
+	tmpl, err = template.ParseFiles("templates/"+templateName)
+	if err != nil {
+		log.Printf("Failed to load %v template: %v\n", record.Tag, err)
+		return
+	}
+
+	smtpPort, err := strconv.Atoi(smtpPortStr)
+	if err != nil {
+		log.Printf("Failed to convert SMTP port to integer: %v\n", err)
+		return
+	}
+
+	mailer := mail.NewDialer(smtpHost, smtpPort, smtpUser, smtpPass)
+	m := mail.NewMessage()
+
+	if record.Email == "" || record.Subject == ""{
+		log.Printf("Invalid record: %+v\n", record)
+		return
+	}
+
+	m.SetHeader("From", senderName+" <"+senderEmail+">")
+	m.SetHeader("To", record.Email)
+	m.SetHeader("Subject", record.Subject)
+
+	body := &bytes.Buffer{}
+	if err := tmpl.Execute(body, msg); err != nil {
+		log.Printf("Failed to execute template: %v\n", err)
+		return
+	}
+
+	m.SetBody("text/html", body.String())
+	if err := mailer.DialAndSend(m); err != nil {
+		log.Printf("Failed to send email: %v\n", err)
+	}else{
+		log.Printf("Sent email Successfully")
+	}
+}