无法使用App Engine邮件包发送电子邮件？

Question

I am new to AppEngine and golang and trying to send an email by using below code and but I do not receive any mail. Cloud you please help to fix it.

Now I am running this code directly from app engine, how to test it from local development server : Edited1: When I am running from local development

dev_appserver.py --smtp_host=smtp.gmail.com --smtp_port=25
--smtp_user=[e-mail] --smtp_password=****** E:\GoWork\src\email\appenginemail

I am getting below error:

 From: [e-mail]
To: Srinadh <[e-mail]>
      Subject: See you tonight
      Body:
        Content-type: text/plain
        Data length: 41
    ERROR    2018-02-02 00:17:00,318 api_server.py:407] Exception while handling mail.Send()
    Traceback (most recent call last):
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\tools\devappserver2\api_server.py", line 375, in _handle_POST
        api_response = _execute_request(request).Encode()
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\tools\devappserver2\api_server.py", line 231, in _execute_request
        make_request()
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\tools\devappserver2\api_server.py", line 226, in make_request
        request_id)
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\api\apiproxy_stub.py", line 151, in MakeSyncCall
        method(request, response)
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\api\mail_stub.py", line 311, in _Send
        self._SendSMTP(mime_message, smtp_lib)
      File "C:\Program Files\google-cloud-sdk\platform\google_appengine\google\appengine\api\mail_stub.py", line 233, in _SendSMTP
        smtp.sendmail(mime_message['From'], tos, mime_message.as_string())
      File "C:\Python27\lib\smtplib.py", line 744, in sendmail
        senderrs[each] = (code, resp)
    TypeError: unhashable instance

Running this code from local development server and also AppEngine

package app

import (
    "net/http"

    "google.golang.org/appengine"
    "google.golang.org/appengine/log"
    "google.golang.org/appengine/mail" )

func init() {
    http.HandleFunc("/sendmail", handleIndex) }

func handleIndex(res http.ResponseWriter, req *http.Request) {
    ctx := appengine.NewContext(req)

    msg := &mail.Message{
        Sender: "[e-mail]",
        To: []string{"Srinadh <[e-mail]>"},
        Subject: "See you tonight",
        Body: "Don't forget our plans. Hark, 'til later.",
    }
    if err := mail.Send(ctx, msg); err != nil {
        log.Errorf(ctx, "Alas, my user, the email failed to sendeth: %v", err)
    } }

Answer 1

GAE is not run on the local server, you have to configure SMTP locally and invoked their methods

Steps:

1. Install SMTP locally (https://www.gazblog.com/2016/07/install-ssmtp-and-setup-with-gmail-on-ubuntu-16-04/)

2. Add this code to send the mail (https://medium.com/@dhanushgopinath/sending-html-emails-using-templates-in-golang-9e953ca32f3d)