如何将原始电子邮件 (MIME) 从 AWS SES 转换为 Gmail

Question

我有一个与我的域帐户关联的Gmail帐户。

AWS SES 会将消息发送到我的 S3 存储桶。从那里，SNS将以原始格式将邮件转发到我的gmail地址。

如何自动将原始邮件转换为标准电子邮件格式？

Answer 1

原始邮件采用标准电子邮件格式。 我认为您想知道的是如何将标准原始电子邮件解析为可以操作的对象，以便您可以将其转发给自己并使其看起来像标准电子邮件。 AWS 提供了有关如何通过 SES 转发具有 lambda 函数的电子邮件的教程，方法是首先将它们存储在 S3 存储桶中： https://aws.amazon.com/blogs/messaging-and-targeting/forward-incoming-email-to-an-external-destination/

如果您按照这些说明操作，您会发现收到的电子邮件是附件，而不是标准电子邮件。 以下代码是对 AWS 提供的 Python 代码的更改，该代码执行您要查找的操作（将其替换为本教程中提供的代码）：

# Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# Altered from original by Adam Winter
#
# This file is licensed under the Apache License, Version 2.0 (the "License").
# You may not use this file except in compliance with the License. A copy of the
# License is located at
#
# http://aws.amazon.com/apache2.0/
#
# This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
# OF ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
import os
import boto3
import email
import re
import html
from botocore.exceptions import ClientError
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication
from email.mime.image import MIMEImage
region = os.environ['Region']
def get_message_from_s3(message_id):
    incoming_email_bucket = os.environ['MailS3Bucket']
    incoming_email_prefix = os.environ['MailS3Prefix']
    if incoming_email_prefix:
        object_path = (incoming_email_prefix + "/" + message_id)
    else:
        object_path = message_id
    object_http_path = (f"http://s3.console.aws.amazon.com/s3/object/{incoming_email_bucket}/{object_path}?region={region}")
    # Create a new S3 client.
    client_s3 = boto3.client("s3")
    # Get the email object from the S3 bucket.
    object_s3 = client_s3.get_object(Bucket=incoming_email_bucket,
        Key=object_path)
    # Read the content of the message.
    file = object_s3['Body'].read()
    file_dict = {
        "file": file,
        "path": object_http_path
    }
    return file_dict
def create_message(file_dict):
    stringMsg = file_dict['file'].decode('utf-8')
    # Create a MIME container.
    msg = MIMEMultipart('alternative')
    sender = os.environ['MailSender']
    recipient = os.environ['MailRecipient']
    # Parse the email body.
    mailobject = email.message_from_string(file_dict['file'].decode('utf-8'))
    #print(mailobject.as_string())
    # Get original sender for reply-to
    from_original = mailobject['Return-Path']
    from_original = from_original.replace('<', '');
    from_original = from_original.replace('>', '');
    print(from_original)
    # Create a new subject line.
    subject = mailobject['Subject']
    print(subject)
    if mailobject.is_multipart():
        index = stringMsg.find('Content-Type: multipart/')
        stringBody = stringMsg[index:]
        #print(stringBody)
        stringData = 'Subject: ' + subject + 'nTo: ' + sender + 'nreply-to: ' + from_original + 'n' + stringBody
        message = {
            "Source": sender,
            "Destinations": recipient,
            "Data": stringData
        }
        return message
        for part in mailobject.walk():
            ctype = part.get_content_type()
            cdispo = str(part.get('Content-Disposition'))
            # case for each common content type
            if ctype == 'text/plain' and 'attachment' not in cdispo:
                bodyPart = MIMEText(part.get_payload(decode=True), 'plain', part.get_content_charset())
                msg.attach(bodyPart)
            if ctype == 'text/html' and 'attachment' not in cdispo:
                mt = MIMEText(part.get_payload(decode=True), 'html', part.get_content_charset())
                email.encoders.encode_quopri(mt)
                del mt['Content-Transfer-Encoding']
                mt.add_header('Content-Transfer-Encoding', 'quoted-printable')
                msg.attach(mt)
            if 'attachment' in cdispo and 'image' in ctype:
                mi = MIMEImage(part.get_payload(decode=True), ctype.replace('image/', ''))
                del mi['Content-Type']
                del mi['Content-Disposition']
                mi.add_header('Content-Type', ctype)
                mi.add_header('Content-Disposition', cdispo)
                msg.attach(mi)
            if 'attachment' in cdispo and 'application' in ctype:
                ma = MIMEApplication(part.get_payload(decode=True), ctype.replace('application/', ''))
                del ma['Content-Type']
                del ma['Content-Disposition']
                ma.add_header('Content-Type', ctype)
                ma.add_header('Content-Disposition', cdispo)
                msg.attach(ma)

    # not multipart - i.e. plain text, no attachments, keeping fingers crossed
    else:
        body = MIMEText(mailobject.get_payload(decode=True), 'UTF-8')
        msg.attach(body)
    # The file name to use for the attached message. Uses regex to remove all
    # non-alphanumeric characters, and appends a file extension.
    filename = re.sub('[^0-9a-zA-Z]+', '_', subject_original)
    # Add subject, from and to lines.
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = recipient
    msg['reply-to'] = mailobject['Return-Path']
    # Create a new MIME object.
    att = MIMEApplication(file_dict["file"], filename)
    att.add_header("Content-Disposition", 'attachment', filename=filename)
    # Attach the file object to the message.
    msg.attach(att)
    message = {
        "Source": sender,
        "Destinations": recipient,
        "Data": msg.as_string()
    }
    return message
def send_email(message):
    aws_region = os.environ['Region']
# Create a new SES client.
    client_ses = boto3.client('ses', region)
    # Send the email.
    try:
        #Provide the contents of the email.
        response = client_ses.send_raw_email(
            Source=message['Source'],
            Destinations=[
                message['Destinations']
            ],
            RawMessage={
                'Data':message['Data']
            }
        )
    # Display an error if something goes wrong.
    except ClientError as e:
        print('send email ClientError Exception')
        output = e.response['Error']['Message']
    else:
        output = "Email sent! Message ID: " + response['MessageId']
    return output
def lambda_handler(event, context):
    # Get the unique ID of the message. This corresponds to the name of the file
    # in S3.
    message_id = event['Records'][0]['ses']['mail']['messageId']
    print(f"Received message ID {message_id}")
    # Retrieve the file from the S3 bucket.
    file_dict = get_message_from_s3(message_id)
    # Create the message.
    message = create_message(file_dict)
    # Send the email and print the result.
    result = send_email(message)
    print(result)

Answer 2

对于那些收到此错误的人：

'bytes' object has no attribute 'encode'

在这一行中：

body = MIMEText(mailobject.get_payload(decode=True), 'UTF-8')

我可以让它工作。我不是这方面的专家，所以代码可能需要一些改进。此外，电子邮件正文还包括 html 标签。但至少它被交付了。

如果解码电子邮件仍然失败，错误消息将显示在您的 CloudWatch 日志中。此外，您还将收到一封包含错误消息的电子邮件。

payload = mailobject.get_payload(decode=True)
try:
    decodedPayload = payload.decode()
    body = MIMEText(decodedPayload, 'UTF-8')
    msg.attach(body)
except Exception as error:
    errorMsg = "An error occured when decoding the email payload:n" + str(error)
    print(errorMsg)
    body = errorMsg + "nPlease download it manually from the S3 bucket."
    msg.attach(MIMEText(body, 'plain'))

要

添加到错误电子邮件中的信息（如主题或发件人地址）取决于您。

只是另一个提示：使用上面的代码，您将收到一个错误，因为找不到subject_original。只需删除以下行。

# The file name to use for the attached message. Uses regex to remove all
# non-alphanumeric characters, and appends a file extension.
filename = re.sub('[^0-9a-zA-Z]+', '_', subject_original)
# Create a new MIME object.
att = MIMEApplication(file_dict["file"], filename)
att.add_header("Content-Disposition", 'attachment', filename=filename)
# Attach the file object to the message.
msg.attach(att)

据我了解，这段代码应该将原始电子邮件添加为附件，这不是我想要的。