Initial commit

Author: Lars van Erp

go.mod

@@ -0,0 +1,3 @@
+module github.com/cmdotcom/email-sdk-golang
+
+go 1.25.4

pkg/emailgateway/README.md

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+# CM Email Gateway API Golang package
+Official API docs: https://developers.cm.com/messaging/docs/email-introduction
+
+## How to use the `emailgateway` package?
+### Installation
+```shell
+go get github.com/cmdotcom/email-sdk-golang/pkg/emailgateway
+```
+
+### Initialize client
+```go
+package main
+
+import "os"
+import (
+    os
+    emailgateway [TODO: Define repo]
+)
+
+func main() {
+	client, err := emailgateway.NewClient(emailgateway.Config{
+	    ProductToken: os.Getenv("CM_EMAIL_GATEWAY_PRODUCT_TOKEN"),
+	})
+	if err != nil {
+		panic(err)
+    }
+}
+```
+
+### Sending an email
+```go
+
+// Client initialization code
+
+email := emailgateway.Email{
+    From: emailgateway.Address{
+        Name:  "CM.com",
+        Email: "no-reply@cm.com",
+    },
+    To: []emailgateway.Address{
+        {
+            Name:  "Example Receiver",
+            Email: "email@example.com",
+        },
+    },
+    Subject:  "My first emailgateway email",
+    HTMLBody: "<h1> Hello world! </h1>",
+    TextBody: "email",
+}
+
+response, err := client.SendTransactionalEmail(email)
+if err != nil {
+	// Handle error
+}
+```

pkg/emailgateway/emailgateway.go

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+package emailgateway
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"time"
+)
+
+type priority string
+
+const (
+	PriorityLow  priority = "LOW"
+	PriorityHigh priority = "HIGH"
+
+	baseURL                      = "https://api.cm.com/email/gateway/v1"
+	defaultHttpTimeout           = 30 * time.Second
+	defaultTransactionalPriority = PriorityHigh
+)
+
+var (
+	ErrUnableToSendEmail = errors.New("unable to send email")
+)
+
+type Client struct {
+	baseClient            *http.Client
+	productToken          string
+	transactionalPriority priority
+}
+
+type Config struct {
+	ProductToken                 string
+	CustomHttpClient             *http.Client
+	DefaultTransactionalPriority priority
+}
+
+func NewClient(config Config) (*Client, error) {
+	var client Client
+
+	if config.ProductToken == "" {
+		return nil, errors.New("config.ProductToken must be set")
+	}
+	client.productToken = config.ProductToken
+
+	client.baseClient = &http.Client{Timeout: defaultHttpTimeout}
+	if config.CustomHttpClient != nil {
+		client.baseClient = config.CustomHttpClient
+	}
+
+	client.transactionalPriority = defaultTransactionalPriority
+	if config.DefaultTransactionalPriority != "" {
+		client.transactionalPriority = config.DefaultTransactionalPriority
+	}
+
+	return &client, nil
+}
+
+type SendEmailResponse struct {
+	Status    int    `json:"status"`
+	Message   string `json:"message"`
+	Success   bool   `json:"success"`
+	MessageID string `json:"messageId"`
+}
+
+func (c *Client) SendTransactionalEmail(email Email) (*SendEmailResponse, error) {
+	emailPriority := c.transactionalPriority
+	if email.Priority != "" {
+		emailPriority = email.Priority
+	}
+
+	mailBody, err := json.Marshal(email)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, baseURL+"/transactional?priority="+string(emailPriority), bytes.NewBuffer(mailBody))
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-CM-PRODUCTTOKEN", c.productToken)
+
+	resp, err := c.baseClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var response SendEmailResponse
+	_ = json.NewDecoder(resp.Body).Decode(&response)
+
+	if resp.StatusCode != http.StatusAccepted {
+		return &response, ErrUnableToSendEmail
+	}
+
+	return &response, nil
+}
+
+func (c *Client) SendMarketingEmail(email Email) (*SendEmailResponse, error) {
+	mailBody, err := json.Marshal(email)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodPost, baseURL+"/transactional", bytes.NewBuffer(mailBody))
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-CM-PRODUCTTOKEN", c.productToken)
+
+	resp, err := c.baseClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var response SendEmailResponse
+	_ = json.NewDecoder(resp.Body).Decode(&response)
+
+	if resp.StatusCode != http.StatusAccepted {
+		return &response, ErrUnableToSendEmail
+	}
+
+	return &response, nil
+}

pkg/emailgateway/mail.go

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+package emailgateway
+
+type ContentType string
+
+const (
+	ContentTypePNG  ContentType = "image/png"
+	ContentTypeJPG  ContentType = "image/jpg"
+	ContentTypeJPEG ContentType = "image/jpeg"
+	ContentTypePDF  ContentType = "application/pdf"
+	ContentTypeDoc  ContentType = "application/doc"
+	ContentTypeDocx ContentType = "application/docx"
+	ContentTypeText ContentType = "application/zip"
+)
+
+type Address struct {
+	Email string `json:"email"`
+	Name  string `json:"name"`
+}
+
+type Attachment struct {
+	Filename string `json:"fileName"`
+	// Content is the base64 encoded content of the attachment
+	Content     string      `json:"content"`
+	ContentType ContentType `json:"contentType"`
+	ContentID   string      `json:"contentId"`
+}
+
+type Email struct {
+	From              Address      `json:"from"`
+	ReplyTo           *Address     `json:"replyTo,omitempty"`
+	To                []Address    `json:"to"`
+	Cc                []Address    `json:"cc,omitempty"`
+	Bcc               []Address    `json:"bcc,omitempty"`
+	Subject           string       `json:"subject"`
+	HTMLBody          string       `json:"html"`
+	TextBody          string       `json:"text"`
+	Attachments       []Attachment `json:"attachments,omitempty"`
+	CustomerReference string       `json:"customerReference,omitempty"`
+	Priority          priority     `json:"-"`
+}

pkg/emailgateway/webhook.go

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+package emailgateway
+
+type WebhookEvent string
+
+const (
+	WebhookEventDelivered    WebhookEvent = "Delivered"
+	WebhookEventOpened       WebhookEvent = "Opened"
+	WebhookEventClicked      WebhookEvent = "Clicked"
+	WebhookEventBounced      WebhookEvent = "Bounced"
+	WebhookEventUnsubscribed WebhookEvent = "Unsubscribed"
+	WebhookEventComplained   WebhookEvent = "Complained"
+)