Lambda@Edge for modify m3u8 structure

lambda_handler.py

import urllib3
import re

def lambda_handler(event, context):
    request = event['Records'][0]['cf']['request']
    response = event['Records'][0]['cf']['response']
    
    # Extract token from query string
    token = None
    for param in request['querystring'].split('&'):
        if param.startswith('token='):
            token = param.split('=')[1]
            break
    
    if not token or response['headers'].get('content-type', [{}])[0].get('value') != 'application/vnd.apple.mpegurl':
        return response
    
    try:
        # Fetch original content
        http = urllib3.PoolManager()
        origin_host = event['Records'][0]['cf']['config']['distributionDomainName']
        url = f"https://{origin_host}{request['uri']}"
        print("url: " + url)
        
        resp = http.request('GET', url)
        original_content = resp.data.decode('utf-8')
        print("original_content: \n" + original_content)
        
        # Modify M3U8 content - only add token to EXT-X-KEY URIs
        def add_token_to_key(match):
            uri_part = match.group(1)
            separator = '&' if '?' in uri_part else '?'
            return f'URI="{uri_part}{separator}token={token}"'
        
        modified_content = re.sub(r'URI="([^"]+)"', add_token_to_key, original_content)
        
        print("modified_content: \n" + modified_content)

        response['body'] = modified_content
        return response
    except Exception as e:
        print(f"Error: {e}")
        return response

Change HLS encryption m3u8 file to append querystring for encryption key request athentication, eg change m3u8 from

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:3
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-KEY:METHOD=AES-128,URI="https://d1nhxos9liml4.cloudfront.net/keys/enc.key",IV=0x00000000000000000000000000000001
#EXTINF:3,
i9243290432_Ott_Hls_Ts_Avc_Aac_16x9_960x540p_3.5Mbps_qvbr_00001.ts
#EXT-X-KEY:METHOD=AES-128,URI="https://d1nhxos9liml4.cloudfront.net/keys/enc.key",IV=0x00000000000000000000000000000002
#EXTINF:3,

to

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:3
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-KEY:METHOD=AES-128,URI="https://d1nhxos9liml4.cloudfront.net/keys/enc.key?token=13s4124",IV=0x00000000000000000000000000000001
#EXTINF:3,
i9243290432_Ott_Hls_Ts_Avc_Aac_16x9_960x540p_3.5Mbps_qvbr_00001.ts
#EXT-X-KEY:METHOD=AES-128,URI="https://d1nhxos9liml4.cloudfront.net/keys/enc.key?token=13s4124",IV=0x00000000000000000000000000000002
#EXTINF:3,