如何在Golang中实现基础的邮件发送功能

package main

import (
    "fmt"
    "net/smtp"
)

func main() {
    // 邮件配置
    from := "your_email@example.com"
    password := "your_password"
    to := []string{"recipient@example.com"}
    smtpHost := "smtp.gmail.com"
    smtpPort := "587"

    // 邮件正文
    subject := "Subject: 测试邮件\r\n"
    body := "这是Go程序发送的一封测试邮件。"
    message := []byte(subject + "\r\n" + body)

    // 认证信息
    auth := smtp.PlainAuth("", from, password, smtpHost)

    // 发送邮件
    err := smtp.SendMail(smtpHost+":"+smtpPort, auth, from, to, message)
    if err != nil {
        fmt.Printf("发送失败: %v\n", err)
        return
    }

    fmt.Println("邮件发送成功！")
}

subject := "Subject: HTML 邮件测试\r\n"
mime := "MIME-version: 1.0;\r\nContent-Type: text/html; charset=\"UTF-8\";\r\n\r\n"
body := "<h1>你好，这是一封HTML邮件</h1><p>支持<strong>加粗</strong>和链接等格式。</p>
                    <div class="aritcle_card">
                        <a class="aritcle_card_img" href="/ai/1521">
                            <img src="https://img.php.cn/upload/ai_manual/000/000/000/175680092127151.png" alt="硅基智能">
                        </a>
                        <div class="aritcle_card_info">
                            <a href="/ai/1521">硅基智能</a>
                            <p>基于Web3.0的元宇宙，去中心化的互联网，高质量、沉浸式元宇宙直播平台，用数字化重新定义直播</p>
                            <div class="">
                                <img src="/static/images/card_xiazai.png" alt="硅基智能">
                                <span>62</span>
                            </div>
                        </div>
                        <a href="/ai/1521" class="aritcle_card_btn">
                            <span>查看详情</span>
                            <img src="/static/images/cardxiayige-3.png" alt="硅基智能">
                        </a>
                    </div>
                "
message := []byte(subject + mime + "\r\n" + body)

func sendEmail(to []string, subject, body, contentType string) error {
    from := "your_email@example.com"
    password := "your_password"
    smtpHost := "smtp.gmail.com"
    smtpPort := "587"

    auth := smtp.PlainAuth("", from, password, smtpHost)

    var mimeHeader string
    if contentType == "html" {
        mimeHeader = "MIME-version: 1.0;\r\nContent-Type: text/html; charset=\"UTF-8\";\r\n\r\n"
    }

    message := []byte("Subject: " + subject + "\r\n" + mimeHeader + "\r\n" + body)
    return smtp.SendMail(smtpHost+":"+smtpPort, auth, from, to, message)
}

sendEmail([]string{"user@domain.com"}, "标题", "<h1>内容</h1>", "html")