Use a batch file request to get file handle URLs for download.

batch_file_request_download.py

"""Example code for using Synapse pre-signed URLs to download directly.

This only uses the Synapse Python client to perform the POST operation to get
the pre-signed URLs and generate signed headers. The `requests` library is used
to fetch the file.

"""

import synapseclient
import json
import requests
import time

# Create client
syn = synapseclient.login(silent=True)

# Get entity
e = syn.get('syn20815185', downloadFile=False)

# Batch file request object
bfr = dict(requestedFiles=[{'associateObjectId': e['id'], 
                            'fileHandleId': e['dataFileHandleId'], 
                            'associateObjectType': 'FileEntity'}],
           includePreSignedURLs=True)

res = syn.restPOST("/fileHandle/batch", json.dumps(bfr), endpoint=syn.fileHandleEndpoint)
headers = syn._generateSignedHeaders(res['requestedFiles'][0]['preSignedURL'])

request = requests.get(res['requestedFiles'][0]['preSignedURL'], headers=headers)