CMSgov/macpro-platform-doc-conversion

import requests
import base64
import json
import boto3
import os
#from aws_requests_auth.aws_auth import AWSRequestsAuth
from aws_requests_auth.boto_utils import BotoAWSRequestsAuth

def lambda_handler(event, context):

    api_endpoint = event['api_endpoint']
    output_location = event['output_location']
    input_bucket = event['input_bucket']
    input_file = event['input_file']

    stage = api_endpoint.split('/')[-2]
    aws_host = api_endpoint.split('/')[-3]


    s3 = boto3.resource('s3')

    
    #Create a file object using the bucket and object key. 
    fileobj = s3.Object(input_bucket, input_file)

    # open the file object and read it into the variable filedata. 
    filedata = fileobj.get()['Body'].read()
    

    # file data will be a binary stream.  We have to decode it 
    html_data = filedata.decode('latin-1')


    # str -> bytes
    input_bytes = html_data.encode()


    # bytes -> base64
    b64_data = base64.b64encode(input_bytes)

    print(f"508 html being converted to pdf:\n\n\n{html_data}\n\n\n")
    print(f"sending request to {api_endpoint}:")

    # ALTERNATE METHOD that doesn't use botocore
    # We need the session token for Lambda since STS is involved
    # https://github.com/DavidMuller/aws-requests-auth#aws-lambda-quickstart-example
    # auth = AWSRequestsAuth(aws_access_key=os.environ['AWS_ACCESS_KEY_ID'],
    #                       aws_secret_access_key=os.environ['AWS_SECRET_ACCESS_KEY'],
    #                       aws_token=os.environ['AWS_SESSION_TOKEN'],
    #                      aws_host=aws_host,
    #                      aws_region='us-east-1',
    #                      aws_service='execute-api')

    auth = BotoAWSRequestsAuth(
                               aws_host=aws_host,
                               aws_region='us-east-1',
                               aws_service='execute-api')


    # Sending post request and saving response as response object 
    r = requests.post(url = api_endpoint, data = b64_data, auth=auth)


    # resp is json with base64 payload
    api_resp = r.json()
    # print(r.content)
    print(r.json)

    # base64 -> bytes
    out_bytes = base64.b64decode(api_resp, validate=True)



    # Perform a basic validation to make sure that the result is a valid PDF file
    # Note this is not 100% reliable (the magic number / file signature)
    if out_bytes[0:4] != b'%PDF':
      raise ValueError('Missing the PDF file signature')
 


    # Write the PDF contents (bytes) to a local file
    # b = binary
    output_file = f'prince-{stage}.pdf'
    s3.Bucket(output_location).put_object(Body=out_bytes,  Key=output_file)



    return { 
        'message' : f"508 PDF written to: {output_location}/{output_file}"
    }