Tiny Flask web service for triggering S3 downloads

download_service.py

from flask import Flask, request, abort
import boto3
import json
import os

app = Flask(__name__)
s3client = boto3.client('s3')

@app.route('/', methods=['GET'])
def index():
    return 'S3 Download Service'

# expects a json payload {"bucket":"", "key":"", "filename":""}
@app.route('/download', methods=['POST'])
def download():
    payload = request.get_json()

    for ele in ['bucket', 'key', 'filename']:
        if ele not in payload:
            abort(400)

    objResponse = s3client.get_object(
      Bucket=payload['bucket'],
      Key=payload['key']
    )

    contents = objResponse['Body'].read()
    with open(os.path.expanduser('~') + '/' + payload['filename'], 'w') as f:
        f.write(contents)
    return json.dumps({'result': 'success'})


if __name__ == '__main__':
    app.run(host="0.0.0.0")