cloud-computing-msc-ai-exam.../example-projects/counter-demo/aws-lambda/lambda_function.py

# import json
import base64
import boto3


def lambda_handler(event, context):
    s3_client = boto3.client('s3')
    response = s3_client.get_object(Bucket='vertsys-counter', Key='eu-central-1')

    counter = int(response['Body'].read().decode('utf-8'))

    debug = ""
    incr = 0
    if 'body' in event:
        body = str(base64.b64decode(event['body']).decode("utf-8"))
        if body.startswith('input'):
            incr = int(body.rsplit('=')[1])
    elif 'input' in event:
        incr = int(event['input'])

    if incr is not 0:
        counter = counter + incr
        response = s3_client.put_object(Bucket='vertsys-counter', Key='eu-central-1', Body=str(counter))

    output = ('<html><head><title>TCPTimeCounter REST Service</title>\n'
              '<meta http-equiv="refresh" content="5"/></head><body>\n'
              '<h2>HS Fulda - TCPTimeCounter REST Service</h2>\n'
              '<p><b>HTML-Output:</b> ' + str(counter) + '</p></body>\n'
              '<form method=POST action="/default/cloudcomp-counter-demo">\n'
              '<input type="hidden" name="input" value="1">\n'
              '<input type="submit" value="Increment"></form>\n'
              # '<hr><b>Lambda Event:</b><br>' + repr(event) + '\n'
              # '<hr><b>Lambda Context:</b><br>' + repr(context) + '\n'
              '</body></html>\n')

    return {
        'statusCode': 200,
        'headers': {
            'Content-Type': 'text/html',
        },
        'body': output
    }