Initial commit

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+max_line_length = 100
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[{Dockerfile,*.yml,*.yaml,*.json}]
+indent_style = tab
+indent_size = 2

.gitignore

@@ -6,10 +6,11 @@
 *.dylib
 
 # Test binary, built with `go test -c`
+tmp/
 *.test
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
 # Dependency directories (remove the comment below to include it)
-# vendor/
+vendor/

.prettierrc

@@ -0,0 +1,6 @@
+{
+  "semi": false,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 100
+}

LICENSE

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright [yyyy] [name of copyright owner]
+   Copyright 2021 Vic Shóstak <vic@shostak.dev> (https://shostak.dev)
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

README.md

@@ -1,2 +1,3 @@
-# go-email-sender
-Simple (but useful) email sender for Go. Support HTML templates and attachments.
+# 📮 Go Email Sender
+
+Simple (but useful) email sender written with pure Go `v1.17`. Support HTML templates and attachments.

go.mod

@@ -0,0 +1,3 @@
+module github.com/koddr/go-email-sender
+
+go 1.17

parse_email_test.go

@@ -0,0 +1,57 @@
+package sender
+
+import (
+	"os"
+	"testing"
+)
+
+func TestParseTemplate(t *testing.T) {
+	// Create folder and file for running tests.
+	_ = os.Mkdir("tmp", 0700)
+	file, err := os.OpenFile("tmp/test.html", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0700)
+	if err != nil {
+		t.Errorf("Sender.parseTemplate() error = %v", err)
+		return
+	}
+	_, err = file.Write([]byte("<h1>Hello, World!</h1>"))
+	if err != nil {
+		t.Errorf("Sender.parseTemplate() error = %v", err)
+		return
+	}
+	defer file.Close()
+
+	// Test cases.
+	type args struct {
+		file string
+		data interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{
+			name: "successfully parsing the template file",
+			args: args{
+				file: "tmp/test.html",
+				data: nil,
+			},
+			want:    "<h1>Hello, World!</h1>",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseTemplate(tt.args.file, tt.args.data)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Sender.parseTemplate() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("Sender.parseTemplate() = %v, want %v", got, tt.want)
+			}
+			os.RemoveAll("tmp") // remove temp folder
+		})
+	}
+}

parse_template.go

@@ -0,0 +1,19 @@
+package sender
+
+import (
+	"bytes"
+	"html/template"
+)
+
+// ParseTemplate ...
+func ParseTemplate(file string, data interface{}) (string, error) {
+	tmpl, errParseFiles := template.ParseFiles(file)
+	if errParseFiles != nil {
+		return "", errParseFiles
+	}
+	buffer := new(bytes.Buffer)
+	if errExecute := tmpl.Execute(buffer, data); errExecute != nil {
+		return "", errExecute
+	}
+	return buffer.String(), nil
+}

sender.go

@@ -0,0 +1,88 @@
+package sender
+
+import (
+	"bytes"
+	"fmt"
+	"mime/quotedprintable"
+	"net/smtp"
+	"strings"
+)
+
+// Sender struct for describe auth data for sending emails.
+type Sender struct {
+	Login          string
+	Password       string
+	SMTPServer     string
+	SMTPServerPort int
+}
+
+// NewEmailSender func for create new email sender.
+// Includes login, password, SMTP server and port.
+func NewEmailSender(login, password, server string, port int) *Sender {
+	return &Sender{login, password, server, port}
+}
+
+// SendHTMLEmail func for send email with given HTML template and data.
+// If template is empty string, it will send with default template.
+func (s *Sender) SendHTMLEmail(template string, dest []string, subject string, data interface{}) error {
+	if template == "" {
+		template = "templates/default.html"
+	}
+	tmpl, errParseTemplate := ParseTemplate(template, data)
+	if errParseTemplate != nil {
+		return errParseTemplate
+	}
+	body := s.writeEmail(dest, "text/html", subject, tmpl)
+	s.sendEmail(dest, subject, body)
+	return nil
+}
+
+// SendPlainEmail func for send plain text email with data.
+func (s *Sender) SendPlainEmail(dest []string, subject, data string) error {
+	body := s.writeEmail(dest, "text/plain", subject, data)
+	s.sendEmail(dest, subject, body)
+	return nil
+}
+
+// writeEmail method for prepare email header and body to send.
+func (s *Sender) writeEmail(dest []string, contentType, subject, body string) string {
+	// Define variables.
+	var message string
+	var header map[string]string
+	var encodedMessage bytes.Buffer
+
+	// Create header.
+	header["From"] = s.Login
+	header["To"] = strings.Join(dest, ",")
+	header["Subject"] = subject
+	header["MIME-Version"] = "1.0"
+	header["Content-Type"] = fmt.Sprintf("%s; charset=\"utf-8\"", contentType)
+	header["Content-Transfer-Encoding"] = "quoted-printable"
+	header["Content-Disposition"] = "inline"
+
+	// Add header values to the message.
+	for key, value := range header {
+		message += fmt.Sprintf("%s:%s\r\n", key, value)
+	}
+
+	// Create writer for make encoding the message.
+	result := quotedprintable.NewWriter(&encodedMessage)
+	result.Write([]byte(body))
+	result.Close()
+
+	// Return the encoded message string.
+	message += "\r\n" + encodedMessage.String()
+	return message
+}
+
+// sendEmail method for send email to destination addresses with subject and body.
+func (s *Sender) sendEmail(dest []string, subject, body string) error {
+	if err := smtp.SendMail(
+		fmt.Sprintf("%s:%d", s.SMTPServer, s.SMTPServerPort),
+		smtp.PlainAuth("", s.Login, s.Password, s.SMTPServer),
+		s.Login, dest, []byte(body),
+	); err != nil {
+		return err
+	}
+	return nil
+}

templates/default.html

@@ -0,0 +1,71 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width" />
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+    <title>✨ The default email from example.com</title>
+    <style type="text/css">
+      body {
+        margin: 0 auto;
+        padding: 0;
+        min-width: 100%;
+        color: #333333;
+        font-family: sans-serif;
+      }
+      table {
+        margin: 50px 0 50px 0;
+      }
+      code {
+        color: #003253;
+        font-family: monospace;
+      }
+      .header {
+        height: 40px;
+        text-align: center;
+        text-transform: uppercase;
+        font-size: 24px;
+        font-weight: bold;
+      }
+      .content {
+        height: 100px;
+        font-size: 18px;
+        line-height: 30px;
+      }
+      .footer {
+        text-align: center;
+        height: 40px;
+        font-size: 14px;
+      }
+      .footer a {
+        color: #777777;
+        text-decoration: none;
+        font-style: normal;
+      }
+    </style>
+  </head>
+  <body bgcolor="#FAFAFA">
+    <table bgcolor="#FFFFFF" width="100%" border="0" cellspacing="0" cellpadding="0">
+      <tr class="header">
+        <td style="padding: 40px">✨ The default email</td>
+      </tr>
+      <tr class="content">
+        <td style="padding: 10px">
+          <p>
+            <strong>Hi,</strong><br />
+            This is the default email from
+            <a href="https://github.com/koddr/go-email-sender" target="_blank" rel="noreferrer"
+              >koddr/go-email-sender</a
+            >
+          </p>
+          <p>Please specify your HTML template in the <code>SendHTMLEmail</code> method.</p>
+        </td>
+      </tr>
+      <tr class="footer">
+        <td style="padding: 40px">
+          👨‍💻 <a href="https://github.com/koddr" target="_blank" rel="noreferrer">@koddr</a>
+        </td>
+      </tr>
+    </table>
+  </body>
+</html>