DreamObjects snippets for DreamScape article

form.html

<form action="https://promethean.objects.dreamhost.com/" method="POST" enctype="multipart/form-data">
  <input type="hidden" name="key" value="uploads/${filename}">
  <input type="hidden" name="AWSAccessKeyId" value="nr-q3_Rsprv94CdsuEpI">
  <input type="hidden" name="acl" value="private">
  <input type="hidden" name="success_action_redirect" value="http://c133.org/tmp/dho-success.html">
  <input type="hidden" name="policy" value="eyJleHBpcmF0aW9uIjogIjIwMTUtMDEtMDFUMDA6MDA6MDBaIiwKICAiY29uZGl0aW9ucyI6IFsKICAgIHsiYnVja2V0IjogImNsZWUifSwKICAgIFsic3RhcnRzLXdpdGgiLCAiJGtleSIsICJ1cGxvYWRzLyJdLAogICAgeyJhY2wiOiAicHJpdmF0ZSJ9LAogICAgeyJzdWNjZXNzX2FjdGlvbl9yZWRpcmVjdCI6ICJodHRwOi8vYzEzMy5vcmcvdG1wL2Roby1zdWNjZXNzLmh0bWwifSwKICAgIFsic3RhcnRzLXdpdGgiLCAiJENvbnRlbnQtVHlwZSIsICIiXQogIF0KfQo=">
  <input type="hidden" name="signature" value="zYcruOMR6qr7o6/Syj001g/trms=">
  <input type="hidden" name="Content-Type" value="image/jpeg">
  File to upload to DreamObjects: <input name="file" type="file">
  <input type="submit" value="Upload File to DreamObjects">
</form>

policy.json

{"expiration": "2015-01-01T00:00:00Z",
    "conditions": [
        {"bucket": "promethean"},
        {"acl": "private"},
        {"success_action_redirect": "http://prometheus.objects.dreamhost.com/success.html"},
        ["starts-with", "$key", "uploads/"],
        ["starts-with", "$Content-Type", ""],
        ["content-length-range", 1048576, 1048576000]
    ]
}

sign.py

#!/usr/bin/env python
import base64
import hmac, hashlib

policy_document = open('policy.json', 'r').read()
policy = base64.b64encode(policy_document)
print("policy: {}\n\n".format(policy))

DHO_SECRET_ACCESS_KEY = 'YOUR SECRET KEY HERE'
signature = base64.b64encode(hmac.new(DHO_SECRET_ACCESS_KEY, policy, hashlib.sha1).digest())
print("signature: {}\n\n".format(signature))