golang net/smtp 获取 smtp 服务器响应 DSN

Question

我正在使用 golang net/smtp 发送邮件

每当我发送到我的 smtp 服务器时，我都需要捕获来自服务器的响应，尤其是 DSN

例如，我的本地 smtp 服务器在邮件末尾给出“ok queued as”

我需要捕获它并在日志中打印

我怎样才能做到这一点

package main

import (
    "log"
    "net/smtp"
)

func sendEmail(msg []byte) {
    c, err := smtp.Dial("localhost:25")
    if err != nil {
        log.Fatal(err)
    }
    if err := c.Mail("sender@example.org"); err != nil {
        log.Fatal(err)
    }

    if err := c.Rcpt("recipient@example.net"); err != nil {
        log.Fatal(err)
    }
    wc, err := c.Data()
    if err != nil {
        log.Fatal(err)
    }

    _, err = wc.Write(msg)
    if err != nil {
        log.Fatal(err)
    }

    //How do I get the response here ??
    err = wc.Close()
    if err != nil {
        log.Fatal(err)
    }

    err = c.Quit()
    if err != nil {
        log.Fatal(err)
    }
}

Answer 1

如评论中所述，您可以使用c.Text.ReadResponse() ：

package main

import (
    "net/smtp"
)

func sendEmail(msg []byte) (code int, message string, err error) {
    c, err := smtp.Dial("localhost:25")
    if err != nil {
        return
    }
    defer c.Quit() // make sure to quit the Client

    if err = c.Mail("sender@example.org"); err != nil {
        return
    }

    if err = c.Rcpt("recipient@example.net"); err != nil {
        return
    }

    wc, err := c.Data()
    if err != nil {
        return
    }
    defer wc.Close() // make sure WriterCloser gets closed

    _, err = wc.Write(msg)
    if err != nil {
        return
    }

    code, message, err = c.Text.ReadResponse(0)
    return
}

---

code ， message和任何err现在传递给调用者，不要在整个代码中使用log.Fatal ，在调用端处理错误。

Answer 2

package main

import (
    "net/smtp"
)

func sendEmail(msg []byte) (code int, message string, err error) {
    c, err := smtp.Dial("localhost:25")
    if err != nil {
        return
    }
    defer c.Quit() // make sure to quit the Client

    if err = c.Mail("sender@example.org"); err != nil {
        return
    }

    if err = c.Rcpt("recipient@example.net"); err != nil {
        return
    }

    wc, err := c.Data()
    if err != nil {
        return
    }

    _, err = wc.Write(msg)
    if err != nil {
        return
    }

    code, message, err = closeData(c) 
    if err != nil {
        return 0, "", err
    }
    
    return code, message, err
}


func closeData(client *smtp.Client) error {
    d := &dataCloser{
        c:           client,
        WriteCloser: client.Text.DotWriter(),
    }

    return d.Close()
}

type dataCloser struct {
    c *smtp.Client
    io.WriteCloser
}

func (d *dataCloser) Close() (int, string, error) {
    d.WriteCloser.Close() // make sure WriterCloser gets closed
    code, message, err := d.c.Text.ReadResponse(250)

    fmt.Printf("Message %v, Error %v\n", message, err)
    return code, message, err
}