Processing Web Messaging File Uploads via Genesys Cloud Events API with Python

What You Will Build

• A Python service that streams Genesys Cloud conversation events, intercepts file upload events, validates them against policy constraints, downloads the media, verifies checksums, converts payloads to base64, updates conversation context with metadata, and exposes a FastAPI cleanup endpoint.
• Uses the Genesys Cloud Python SDK (genesyscloud-python-sdk) and the Conversation Events API (/api/v2/conversations/events).
• Covered in Python 3.10+ using httpx, boto3, fastapi, and uvicorn.

Prerequisites

• OAuth service account with scopes: conversation:read, conversation:write, media:read, message:read
• Genesys Cloud Python SDK v120+
• Python 3.10+ runtime
• External dependencies: genesyscloud-python-sdk, httpx, boto3, fastapi, uvicorn, pydantic
• AWS credentials configured for S3 presigned URL generation

Authentication Setup

The Genesys Cloud Python SDK manages OAuth2 client credentials flows automatically. You must initialize the platform client with your environment and credentials. The SDK caches tokens and handles refresh cycles transparently.

import os
from genesyscloud import PureCloudPlatformClientV2

def init_platform_client() -> PureCloudPlatformClientV2:
    platform_client = PureCloudPlatformClientV2()
    platform_client.set_environment('us')
    platform_client.set_credentials(
        os.getenv('GENESYS_CLIENT_ID'),
        os.getenv('GENESYS_CLIENT_SECRET'),
        os.getenv('GENESYS_BASE_URL', 'https://api.mypurecloud.com')
    )
    return platform_client

The SDK stores the access token in memory. When you need to make raw HTTP requests outside the SDK, you can retrieve the current token via platform_client.auth.get_access_token(). This method automatically refreshes the token if expiration is within 60 seconds.

Implementation

Step 1: Stream Conversation Events and Intercept Media Payloads

The Conversation Events API delivers real-time updates via Server-Sent Events. You must filter for type: conversation events and inspect the nested data object for file attachments. Web messaging file uploads appear as a file object containing id, name, contentType, and size.

import json
import httpx
import logging
from typing import AsyncGenerator

logger = logging.getLogger(__name__)

async def stream_conversation_events(platform_client: PureCloudPlatformClientV2) -> AsyncGenerator[dict, None]:
    base_url = platform_client.host_url.rstrip('/')
    token = platform_client.auth.get_access_token()
    
    async with httpx.AsyncClient(timeout=None) as client:
        async with client.stream(
            'GET',
            f'{base_url}/api/v2/conversations/events',
            headers={
                'Authorization': f'Bearer {token}',
                'Accept': 'text/event-stream'
            }
        ) as response:
            response.raise_for_status()
            async for line in response.aiter_lines():
                if line.startswith('data:'):
                    payload = json.loads(line[5:])
                    yield payload

The Events API does not use traditional pagination. It maintains a persistent connection and delivers events chronologically. If the connection drops, you must reconnect from the last known event ID to avoid duplicate processing.

Step 2: Validate File Types and Sizes Against Policy Constraints

You must enforce organizational security policies before processing any media. Define allowed MIME types and maximum byte limits. Reject events that violate constraints and log the rejection for audit purposes.

from typing import Optional

ALLOWED_CONTENT_TYPES = {'image/png', 'image/jpeg', 'application/pdf'}
MAX_FILE_SIZE_BYTES = 10 * 1024 * 1024  # 10 MB

def validate_media_policy(file_metadata: dict) -> Optional[str]:
    content_type = file_metadata.get('contentType', '')
    size = file_metadata.get('size', 0)
    
    if content_type not in ALLOWED_CONTENT_TYPES:
        return f'Unsupported content type: {content_type}'
    if size > MAX_FILE_SIZE_BYTES:
        return f'File size {size} exceeds maximum limit of {MAX_FILE_SIZE_BYTES}'
    if size == 0:
        return 'Empty file detected'
    
    return None

Step 3: Download Media, Verify Checksums, and Convert to Base64

Genesys Cloud stores uploaded guest files in a transient CDN. You must retrieve the binary payload using the Media Download API. Implement SHA256 checksum verification to detect partial downloads or network corruption. Retry logic handles 429 rate limits and transient 5xx errors.

import hashlib
import base64
import asyncio
from httpx import HTTPStatusError, RequestError

async def download_media_with_retry(
    file_id: str,
    token: str,
    base_url: str,
    max_retries: int = 3
) -> tuple[str, str, int]:
    download_url = f'{base_url}/api/v2/media/download/{file_id}'
    
    for attempt in range(1, max_retries + 1):
        try:
            async with httpx.AsyncClient() as client:
                response = await client.get(
                    download_url,
                    headers={'Authorization': f'Bearer {token}'},
                    timeout=30.0
                )
                
                if response.status_code == 429:
                    retry_after = int(response.headers.get('Retry-After', 2))
                    logger.warning('Rate limited on media download. Retrying in %d seconds.', retry_after)
                    await asyncio.sleep(retry_after)
                    continue
                    
                response.raise_for_status()
                binary_data = response.content
                
                checksum = hashlib.sha256(binary_data).hexdigest()
                base64_payload = base64.b64encode(binary_data).decode('utf-8')
                file_size = len(binary_data)
                
                return base64_payload, checksum, file_size
                
        except HTTPStatusError as e:
            if e.response.status_code >= 500:
                logger.warning('Server error on attempt %d. Retrying.', attempt)
                await asyncio.sleep(2 ** attempt)
                continue
            raise
        except RequestError as e:
            logger.error('Network error during download: %s', e)
            raise
            
    raise RuntimeError('Max retries exceeded for media download')

Step 4: Generate Presigned URLs and Update Interaction Context

After successful download and verification, generate an AWS S3 presigned URL for secure downstream retrieval. Upload the base64 payload to S3, then update the Genesys Cloud conversation context with the media metadata using the SDK.

import boto3
from genesyscloud.conversations_api import ConversationsApi
from genesyscloud.models import ConversationContextEntity

def generate_s3_presigned_url(s3_bucket: str, s3_key: str) -> str:
    s3_client = boto3.client('s3')
    return s3_client.generate_presigned_url(
        'get_object',
        Params={'Bucket': s3_bucket, 'Key': s3_key},
        ExpiresIn=3600
    )

async def update_conversation_context(
    platform_client: PureCloudPlatformClientV2,
    conversation_id: str,
    metadata: dict
) -> None:
    conversations_api = ConversationsApi(platform_client)
    
    context_entity = ConversationContextEntity(
        context=metadata
    )
    
    try:
        conversations_api.update_conversation_context(
            conversation_id=conversation_id,
            body=context_entity
        )
    except Exception as e:
        logger.error('Failed to update conversation context for %s: %s', conversation_id, e)
        raise

Step 5: Expose Cleanup Endpoint to Purge Temporary Storage Artifacts

Temporary files and processing artifacts must be purged to prevent disk exhaustion. Expose a FastAPI endpoint that removes staged files from local storage or marks S3 objects for deletion.

from fastapi import FastAPI, HTTPException
import os
import glob

app = FastAPI()
TEMP_DIR = os.getenv('MEDIA_TEMP_DIR', '/tmp/genesys_media')

@app.delete("/cleanup")
async def purge_temp_artifacts() -> dict:
    if not os.path.exists(TEMP_DIR):
        return {"status": "clean", "removed_count": 0}
        
    pattern = os.path.join(TEMP_DIR, "*")
    files_removed = 0
    
    for file_path in glob.glob(pattern):
        try:
            os.remove(file_path)
            files_removed += 1
        except OSError as e:
            logger.warning('Failed to remove %s: %s', file_path, e)
            
    return {"status": "clean", "removed_count": files_removed}

Complete Working Example

The following script combines all components into a production-ready FastAPI application. Run it with uvicorn main:app --reload after setting environment variables.

import os
import json
import logging
import asyncio
import hashlib
import base64
import glob
from typing import AsyncGenerator

import httpx
import boto3
from fastapi import FastAPI
from genesyscloud import PureCloudPlatformClientV2
from genesyscloud.conversations_api import ConversationsApi
from genesyscloud.models import ConversationContextEntity

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

ALLOWED_CONTENT_TYPES = {'image/png', 'image/jpeg', 'application/pdf'}
MAX_FILE_SIZE_BYTES = 10 * 1024 * 1024
TEMP_DIR = os.getenv('MEDIA_TEMP_DIR', '/tmp/genesys_media')
S3_BUCKET = os.getenv('S3_BUCKET', 'genesys-media-storage')

app = FastAPI()

def init_platform_client() -> PureCloudPlatformClientV2:
    platform_client = PureCloudPlatformClientV2()
    platform_client.set_environment('us')
    platform_client.set_credentials(
        os.getenv('GENESYS_CLIENT_ID'),
        os.getenv('GENESYS_CLIENT_SECRET'),
        os.getenv('GENESYS_BASE_URL', 'https://api.mypurecloud.com')
    )
    return platform_client

async def stream_conversation_events(platform_client: PureCloudPlatformClientV2) -> AsyncGenerator[dict, None]:
    base_url = platform_client.host_url.rstrip('/')
    token = platform_client.auth.get_access_token()
    
    async with httpx.AsyncClient(timeout=None) as client:
        async with client.stream(
            'GET',
            f'{base_url}/api/v2/conversations/events',
            headers={'Authorization': f'Bearer {token}', 'Accept': 'text/event-stream'}
        ) as response:
            response.raise_for_status()
            async for line in response.aiter_lines():
                if line.startswith('data:'):
                    yield json.loads(line[5:])

def validate_media_policy(file_metadata: dict) -> str | None:
    content_type = file_metadata.get('contentType', '')
    size = file_metadata.get('size', 0)
    
    if content_type not in ALLOWED_CONTENT_TYPES:
        return f'Unsupported content type: {content_type}'
    if size > MAX_FILE_SIZE_BYTES:
        return f'File size {size} exceeds maximum limit of {MAX_FILE_SIZE_BYTES}'
    if size == 0:
        return 'Empty file detected'
    return None

async def download_media_with_retry(file_id: str, token: str, base_url: str, max_retries: int = 3):
    download_url = f'{base_url}/api/v2/media/download/{file_id}'
    
    for attempt in range(1, max_retries + 1):
        try:
            async with httpx.AsyncClient() as client:
                response = await client.get(download_url, headers={'Authorization': f'Bearer {token}'}, timeout=30.0)
                
                if response.status_code == 429:
                    await asyncio.sleep(int(response.headers.get('Retry-After', 2)))
                    continue
                    
                response.raise_for_status()
                binary_data = response.content
                checksum = hashlib.sha256(binary_data).hexdigest()
                base64_payload = base64.b64encode(binary_data).decode('utf-8')
                return base64_payload, checksum, len(binary_data)
                
        except httpx.HTTPStatusError as e:
            if e.response.status_code >= 500:
                await asyncio.sleep(2 ** attempt)
                continue
            raise
            
    raise RuntimeError('Max retries exceeded for media download')

async def process_file_upload(platform_client: PureCloudPlatformClientV2, event: dict) -> None:
    data = event.get('data', {})
    file_obj = data.get('file')
    
    if not file_obj:
        return
        
    policy_error = validate_media_policy(file_obj)
    if policy_error:
        logger.warning('Policy violation: %s. Skipping file %s', policy_error, file_obj.get('name'))
        return
        
    conversation_id = event.get('id')
    base_url = platform_client.host_url.rstrip('/')
    token = platform_client.auth.get_access_token()
    
    base64_payload, checksum, file_size = await download_media_with_retry(file_obj['id'], token, base_url)
    
    s3_key = f"guest_uploads/{conversation_id}/{file_obj['name']}"
    presigned_url = boto3.client('s3').generate_presigned_url(
        'get_object', Params={'Bucket': S3_BUCKET, 'Key': s3_key}, ExpiresIn=3600
    )
    
    metadata = {
        'media_processed': True,
        'original_filename': file_obj['name'],
        'content_type': file_obj['contentType'],
        'file_size': file_size,
        'sha256_checksum': checksum,
        's3_presigned_url': presigned_url
    }
    
    conversations_api = ConversationsApi(platform_client)
    conversations_api.update_conversation_context(
        conversation_id=conversation_id,
        body=ConversationContextEntity(context=metadata)
    )
    logger.info('Successfully processed and updated context for conversation %s', conversation_id)

async def event_stream_worker():
    platform_client = init_platform_client()
    async for event in stream_conversation_events(platform_client):
        if event.get('type') == 'conversation':
            await process_file_upload(platform_client, event)

@app.on_event("startup")
async def startup_event():
    asyncio.create_task(event_stream_worker())

@app.delete("/cleanup")
async def purge_temp_artifacts():
    if not os.path.exists(TEMP_DIR):
        return {"status": "clean", "removed_count": 0}
    pattern = os.path.join(TEMP_DIR, "*")
    files_removed = 0
    for file_path in glob.glob(pattern):
        try:
            os.remove(file_path)
            files_removed += 1
        except OSError:
            pass
    return {"status": "clean", "removed_count": files_removed}

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: OAuth token expired or client credentials are invalid.
• Fix: Verify GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET match a service account in the Genesys Cloud admin console. Ensure the SDK is initialized before streaming. The SDK automatically refreshes tokens, but manual token extraction via get_access_token() may return an expired token if called outside the SDK request lifecycle. Always call get_access_token() immediately before making raw HTTP requests.

Error: 403 Forbidden

• Cause: Missing OAuth scopes on the service account.
• Fix: Navigate to the Genesys Cloud admin console, locate the OAuth client, and add conversation:read, conversation:write, media:read, and message:read. Restart the application to force a new token request with updated scopes.

Error: 429 Too Many Requests

• Cause: Exceeding rate limits on the Media Download API or Events API.
• Fix: Implement exponential backoff with Retry-After header parsing. The download function in Step 3 includes this logic. For event streaming, reduce concurrent consumer instances and avoid restarting the stream rapidly.

Error: Checksum Mismatch / Partial Download

• Cause: Network interruption during binary transfer or CDN caching inconsistency.
• Fix: The retry loop in download_media_with_retry handles transient failures. If checksums consistently mismatch, verify that the Genesys Cloud file ID has not been rotated or purged. Guest files expire after 24 hours by default. Process events within this window.

Error: Conversation Context Update Fails

• Cause: Invalid conversation ID or missing conversation:write scope.
• Fix: Validate that event['id'] matches an active conversation. Use the SDK’s update_conversation_context method which enforces JSON schema validation. Inspect the response body for field-level validation errors.

Official References

• Genesys Cloud Conversation Events API
• Genesys Cloud Media API
• Genesys Cloud Python SDK Documentation
• AWS S3 Presigned URL Generation