From a0b8169ab4c770663f231a167d36a8ff8ef3b755 Mon Sep 17 00:00:00 2001
From: Joe Paul <joeirimpan@gmail.com>
Date: Mon, 20 Jun 2022 17:45:50 +0530
Subject: [PATCH] feat: Add AWS-SES messenger

---
 config.sample.toml |   9 ++++
 go.mod             |   1 +
 go.sum             |   2 +
 messenger/ses.go   | 130 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 142 insertions(+)
 create mode 100644 messenger/ses.go

diff --git a/config.sample.toml b/config.sample.toml
index 3e2a87b..7d143c7 100644
--- a/config.sample.toml
+++ b/config.sample.toml
@@ -13,4 +13,13 @@ config = '''
     "message_type": "",
     "sender_id": ""
 }
+'''
+
+[messenger.ses]
+config = '''
+{
+    "access_key": "",
+    "secret_key": "",
+    "region": "",
+}
 '''
\ No newline at end of file
diff --git a/go.mod b/go.mod
index 9fad21a..978fe2c 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ require (
 	github.com/go-chi/chi v1.5.4
 	github.com/knadh/koanf v1.4.0
 	github.com/knadh/listmonk v1.1.0
+	github.com/knadh/smtppool v0.4.0
 	github.com/spf13/pflag v1.0.5
 )
 
diff --git a/go.sum b/go.sum
index bbd57d2..12e2cba 100644
--- a/go.sum
+++ b/go.sum
@@ -86,6 +86,8 @@ github.com/knadh/koanf v1.4.0/go.mod h1:1cfH5223ZeZUOs8FU2UdTmaNfHpqgtjV0+NHjRO4
 github.com/knadh/listmonk v1.1.0 h1:X5qIOKuyC3OxfKGf82C1yTIMHwsjWxvf1gzn2ulbXOo=
 github.com/knadh/listmonk v1.1.0/go.mod h1:XlnRvP4GDUZXZNq0+Yl8SqComqpZ9VoS3ZAzdakaiHs=
 github.com/knadh/smtppool v0.2.1/go.mod h1:3DJHouXAgPDBz0kC50HukOsdapYSwIEfJGwuip46oCA=
+github.com/knadh/smtppool v0.4.0 h1:335iXPwZ6katJVhauV4O6e8uPvvPmO6YLrfDQhb6UvE=
+github.com/knadh/smtppool v0.4.0/go.mod h1:3DJHouXAgPDBz0kC50HukOsdapYSwIEfJGwuip46oCA=
 github.com/knadh/stuffbin v1.1.0/go.mod h1:yVCFaWaKPubSNibBsTAJ939q2ABHudJQxRWZWV5yh+4=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
diff --git a/messenger/ses.go b/messenger/ses.go
new file mode 100644
index 0000000..a70ab71
--- /dev/null
+++ b/messenger/ses.go
@@ -0,0 +1,130 @@
+package messenger
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/ses"
+	"github.com/knadh/smtppool"
+)
+
+const (
+	ContentTypeHTML  = "html"
+	ContentTypePlain = "plain"
+)
+
+type sesCfg struct {
+	AccessKey string `json:"access_key"`
+	SecretKey string `json:"secret_key"`
+	Region    string `json:"region"`
+	Log       bool   `json:"log"`
+}
+
+type sesMessenger struct {
+	cfg    sesCfg
+	client *ses.SES
+}
+
+func (s sesMessenger) Name() string {
+	return "ses"
+}
+
+// Push sends the sms through pinpoint API.
+func (s sesMessenger) Push(msg Message) error {
+	// convert attachments to smtppool.Attachments
+	a := make([]smtppool.Attachment, 0, len(msg.Attachments))
+	for i := 0; i < len(msg.Attachments); i++ {
+		a[i] = smtppool.Attachment{
+			Filename: msg.Attachments[i].Name,
+			Header:   msg.Attachments[i].Header,
+			Content:  msg.Attachments[i].Content,
+		}
+	}
+
+	email := smtppool.Email{
+		From:        msg.From,
+		To:          msg.To,
+		Subject:     msg.Subject,
+		Sender:      msg.From,
+		Headers:     msg.Headers,
+		Attachments: a,
+	}
+
+	switch {
+	case msg.ContentType == ContentTypePlain:
+		email.Text = msg.Body
+	case msg.ContentType == ContentTypeHTML:
+		email.HTML = msg.Body
+	}
+
+	emailB, err := email.Bytes()
+	if err != nil {
+		return err
+	}
+
+	to := make([]*string, 0, len(msg.To))
+	for i := 0; i < len(msg.To); i++ {
+		to = append(to, &msg.To[i])
+	}
+
+	input := &ses.SendRawEmailInput{
+		Source:       &msg.From,
+		Destinations: to,
+		RawMessage: &ses.RawMessage{
+			Data: emailB,
+		},
+	}
+
+	out, err := s.client.SendRawEmail(input)
+	if err != nil {
+		return err
+	}
+
+	if s.cfg.Log {
+		log.Printf("successfully sent email to %s: %#+v", msg.Subscriber.Email, out)
+	}
+
+	return nil
+}
+
+func (s sesMessenger) Flush() error {
+	return nil
+}
+
+func (s sesMessenger) Close() error {
+	return nil
+}
+
+// NewAWSSES creates new instance of pinpoint
+func NewAWSSES(cfg []byte) (Messenger, error) {
+	var c sesCfg
+	if err := json.Unmarshal(cfg, &c); err != nil {
+		return nil, err
+	}
+
+	if c.Region == "" {
+		return nil, fmt.Errorf("invalid region")
+	}
+	if c.AccessKey == "" {
+		return nil, fmt.Errorf("invalid access_key")
+	}
+	if c.SecretKey == "" {
+		return nil, fmt.Errorf("invalid secret_key")
+	}
+
+	sess := session.Must(session.NewSession())
+	svc := ses.New(sess,
+		aws.NewConfig().
+			WithCredentials(credentials.NewStaticCredentials(c.AccessKey, c.SecretKey, "")).
+			WithRegion(c.Region),
+	)
+
+	return sesMessenger{
+		client: svc,
+		cfg:    c,
+	}, nil
+}