function-to-email-notification-for-new-file-uploaded.py

function-to-email-notification-for-new-file-uploaded.py

print('Loading function')


# source - https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-presigned-urls.html

import logging
import boto3
from botocore.exceptions import ClientError

import json

import os
sns_topic_arn = os.environ['sns_topic_arn']


s3_client  = boto3.client('s3')
sns_client = boto3.client('sns')


def create_presigned_url(bucket_name, object_name, expiration=3600):
    """Generate a presigned URL to share an S3 object

    :param bucket_name: string
    :param object_name: string
    :param expiration: Time in seconds for the presigned URL to remain valid
    :return: Presigned URL as string. If error, returns None.
    """

    # Generate a presigned URL for the S3 object
    #s3_client = boto3.client('s3')
    try:
        response = s3_client.generate_presigned_url('get_object',
                                                    Params={'Bucket': bucket_name,
                                                            'Key': object_name},
                                                    ExpiresIn=expiration)
    except ClientError as e:
        logging.error(e)
        return None

    # The response contains the presigned URL
    return response


# useful links
# https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/python/example_code/s3/s3_basics/presigned_url.py
# https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/s3.html#S3.Client.generate_presigned_url
# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-presigned-urls.html
# https://docs.aws.amazon.com/lambda/latest/dg/with-s3-tutorial.html


def lambda_handler(event, context):
    #print("Received event: " + json.dumps(event, indent=2))
    #print('This is sns_topic_arn: {}.'.format(sns_topic_arn))
    

    # Get the object from the event and show its content type
    bucket_name = event['Records'][0]['s3']['bucket']['name']
    #key = urllib.parse.unquote_plus(event['Records'][0]['s3']['object']['key'], encoding='utf-8')
    object_name = event['Records'][0]['s3']['object']['key']
    
    
    try:
        #response = s3_client.get_object(Bucket=bucket, Key=key)
        #print("CONTENT TYPE: " + response['ContentType'])
        print('Object name `{}` from bucket `{}`.'.format(object_name, bucket_name))
        
        #url = s3_client.generate_presigned_url(
        #    ClientMethod='get_object',
        #    Params={'Bucket': bucket, 'Key': key},
        #    ExpiresIn='25200' #7 days
        #)
        
        #print('This is the result URL - {} '.format(url))
        
        #presigned_url_for_email = '<a href="{}">Your private link for download</a>'.format(url)
        #print(presigned_url_for_email)
        
        url = create_presigned_url(bucket_name, object_name)
        
        print(url)
        
        response = sns_client.publish(
             TopicArn=sns_topic_arn,
             Message='Notification for bucket {}. \nA new file name {} was added. \n\nHere is the link for download: \n\n {} \n\nPlease let us know if you need a new link as for security they expire after 1 hour. \nThank you. \nGEL fantastic staff.'.format(bucket_name, object_name, url),
             Subject='Bucket notification - new file {}'.format(object_name)
        )
        
        return 0
        #response['ContentType']
        
    except Exception as e:
        print(e)
        print('Error getting object {} from bucket {}. Make sure they exist and your bucket is in the same region as this function.'.format(key, bucket))
        raise e