6.2.2. Create the Form

To communicate between your website and your Cloud Files account, create a form using the following format in your website:

  <form action="<CF-url>" method="POST" enctype="multipart/form-data">
    <input type="hidden" name="redirect" value="<redirect-url>" />
    <input type="hidden" name="max_file_size" value="<bytes>" />
    <input type="hidden" name="max_file_count" value="<count>" />
    <input type="hidden" name="expires" value="<unix-timestamp>" />
    <input type="hidden" name="signature" value="<hmac>" />
    <input type="file" name="file1" /><br />
    <input type="submit" />
  </form>
            

Required: Form action is the Cloud Files URL (CF-url) to the destination where files will be uploaded. For instance, https://storage.clouddrive.com/v1/CF_xer7_34/container. The name of each uploaded object will have the <CF-url> appended to the front of it. Your users upload directly to root of the container.

You may also include a prefix to separate uploads, such as assigning each user a certain prefix: https://storage.clouddrive.com/v1/CF_xer7_34/container/user_prefix.

Required: The form method must be "POST" and the enctype must be set as “multipart/form-data”.

Optional: The redirect attribute is the URL of the page that displays on your website after the form processes. The URL will have status and message query parameters added to it, indicating the HTTP status code for the upload (2xx is success) and a possible message for further information if there is an error, such as “max_file_size exceeded”.

Required: The max_file_size attribute must be included and indicates the largest single file upload allowed, in bytes. Although you may limit the size of the individual file uploaded to your Cloud Files account here, the max_file_size may not exceed 5 GB.

Required: The max_file_count attribute indicates the maximum number of files that can be uploaded with the form.

Required: The expires attribute is the Unix timestamp when the form is invalidated. This gives your website users a limited time to have the form open. Time must be in Unix epoch format.

Required: The signature attribute is the HMAC-SHA1 signature of the form. Here is sample code for computing the signature in Python:

  import hmac
  from hashlib import sha1
  from time import time
  path = '/v1/account/container/object_prefix'
  redirect = 'https://myserver.com/some-page'
  max_file_size = 104857600
  max_file_count = 10
  expires = int(time() + 600)
  key = 'mykey'
  hmac_body = '%s\n%s\n%s\n%s\n%s' % (path, redirect,
      max_file_size, max_file_count, expires)
  signature = hmac.new(key, hmac_body, sha1).hexdigest()
              

Required: The type="file" field defines the form file field. At least one entry is required to allow your users to select and upload a file, but additional fields may be added for multiple files. The number of entries should not, however, exceed the max_file_count. Each type="file" field must have a different name.

Note that the type="file" field(s) must be at the end of the form code in order for Cloud Files to process the uploads properly.