GoogleAPI：错误400：需要收件人地址，invalidArgument

Question

func SendMail() {

b, err := ioutil.ReadFile("credentials.json")
if err != nil {
    log.Fatalf("Unable to read client secret file: %v", err)
}

config, err := google.ConfigFromJSON(b, gmail.MailGoogleComScope)
if err != nil {
    log.Fatalf("Unable to parse client secret file to config: %v", 
err)
}
client := getClient(config)

srv, err := gmail.New(client)
if err != nil {
    log.Fatalf("Unable to retrieve Gmail client: %v", err)
}

user := "me"
mailtext := `From: [e-mail]
To: [e-mail]
Subject: Saying Hello
Date: Thu, 8 Oct 2020 09:55:06 -0600
Message-ID: <[e-mail]>

This is a message just to say hello.
So, "Hello".
`
raw := base64.URLEncoding.EncodeToString([]byte(mailtext))

var message gmail.Message
message.Id = "Msg 2"
message.LabelIds = []string{"SENT"}
message.Raw = raw

doFunc := srv.Users.Messages.Send(user, &message)
m, err := doFunc.Do()
if err != nil {
    println(err.Error())
    println("Message not sent")
} else {
    fmt.Printf("%+v", m)
}

googleapi: Error 400: Recipient address required, invalidArgument

谢谢你的帮助！！！

Answer 1

null

null

    mailtext := `
    From: [e-mail]
    To: [e-mail]
    Subject: Saying Hello
    Date: Thu, 8 Oct 2020 09:55:06 -0600
    Message-ID: <[e-mail]>

    This is a message just to say hello.
    So, "Hello".
    `
    raw :=  base64.URLEncoding.EncodeToString([]byte(mailtext))

     // create gmail.Message

     var message gmail.Message
     message.Id = "Msg 1"
     message.LabelIds = []string{"SENT"}

    user := "me"
    // Modified
    mailtext := `From: [e-mail]
To: [e-mail]
Subject: Saying Hello
Date: Thu, 8 Oct 2020 09:55:06 -0600
Message-ID: <[e-mail]>

This is a message just to say hello.
So, "Hello".`
    raw := base64.URLEncoding.EncodeToString([]byte(mailtext))

    // create gmail.Message

    var message gmail.Message
    message.Id = "Msg 1"
    message.LabelIds = []string{"SENT"}
    message.Raw = raw  // Added

  mailtext := "From: [e-mail]\nTo: [e-mail]\nSubject: Saying Hello\nDate: Thu, 8 Oct 2020 09:55:06 -0600\nMessage-ID: <[e-mail]>\n\nThis is a message just to say hello.\nSo, \"Hello\"."

null