Here’s how to make a simple web page to allow people to upload files to an Amazon AWS bucket from your site. Some of the details are a bit murky, but it does seem to work. You will need a bucket with upload permissions enabled (and probably public downloads disabled).
First, you need a policy, saved as a text file. Here’s mine:
{ "expiration": "2090-12-01T12:00:00.000Z",
"conditions": [
{"bucket": "MY-BUCKET"},
["starts-with", "$key", "upload"],
{"acl": "public-read"},
{"success_action_redirect": "http://example.com/successful_redirect.html"},
{"x-amz-meta-uuid": "14365123651274"},
]
}
Replace MY-BUCKET with the name of your AWS bucket, and the successful_redirect URL with where the user should be taken when an upload succeeds. I’ve no idea what the x-amz-meta-uuid does, to be honest; that’s the one of Amazon’s example.
Now, you need to encode this policy and sign it with your AWS secret key. Save the policy as upload_policy and use this python script:
import base64
import hmac
import hashlib
aws_secret_key = 'MY-SECRET-KEY'
with open('upload_policy', 'r') as f:
policy_document = f.read()
policy = base64.b64encode(policy_document)
signature = base64.b64encode(hmac.new(aws_secret_key, policy, hashlib.sha1).digest())
print 'Policy:'
print policy
print 'Signature:'
print signature
Replace MY-SECRET-KEY with your Amazon AWS secret key. The script will print out policy and signature values, which you should paste into this HTML:
<table>
<form action="http://MY-BUCKET-NAME.s3.amazonaws.com/" method="post" enctype="multipart/form-data">
<input type="hidden" name="key" value="upload-${filename}"/><br/>
<input type="hidden" name="acl" value="public-read"/>
<input type="hidden" name="success_action_redirect" value="http://example.com/successful_upload.html"/>
<input type="hidden" name="x-amz-meta-uuid" value="14365123651274"/>
<input type="hidden" name="AWSAccessKeyId" value="MY-ACCESS-KEY"/>
<input type="hidden" name="Policy" value="MY-POLICY"/>
<input type="hidden" name="Signature" value="MY-POLICY-SIGNATURE"/>
<tr><td>File</td><td><input type="file" name="file"/></td></tr>
<!-- The elements after this will be ignored -->
<tr><td></td><td><input type="submit" name="submit" value="Upload"/></td></tr>
</form>
</table>
Once again, replace MY-BUCKET-NAME with your bucket, and the successful_upload URL with one appropriate for your site. MY-ACCESS-KEY needs replacing with your AWS access key.
Files that are uploaded should then appear in your AWS bucket.