ska 0.5

Client side

Signing URLs is as simple as follows.

Required imports.

>>> from ska import sign_url

Producing a signed URL.

>>> signed_url = sign_url(
>>>     auth_user='user', secret_key='your-secret_key', url='http://e.com/api/'
>>> )
http://e.com/api/?valid_until=1378045287.0&auth_user=user&signature=YlZpLFsjUKBalL4x5trhkeEgqE8%3D

Default lifetime of a signature is 10 minutes (600 seconds). If you want it to be different, provide a lifetime argument to sign_url function.

Default name of the (GET) param holding the generated signature value is signature. If you want it to be different, provide a signature_param argument to sign_url function.

Default name of the (GET) param holding the auth_user value is auth_user. If you want it to be different, provide a auth_user_param argument to sign_url function.

Default name of the (GET) param holding the valid_until value is valid_until. If you want it to be different, provide a valid_until_param argument to sign_url function.

Note, that by default a suffix ‘?’ is added after the given url and generated signature params. If you want that suffix to be custom or gone, provide a suffix argument to the sign_url function.

With all customisations, it would look as follows.

>>> signed_url = sign_url(
>>>     auth_user='user', secret_key='your-secret_key', lifetime=120,
>>>     url='http://e.com/api/', signature_param='signature',
>>>     auth_user_param='auth_user', valid_until_param='valid_until'
>>> )

You may now proceed with the signed URL request. If you use the famous requests library, it would be as follows.

>>> import requests
>>> requests.get(signed_url)

If you want to use POST method instead, you would likely want to get a dictionary back, in order to append it to the POST data later.

Required imports.

>>> from ska import signature_to_dict

Producing a dictionary containing the signature data, ready to be put into the request (for example POST) data. All customisations mentioned above for the sign_url function, also apply to the signature_to_dict.

>>> signature_dict = signature_to_dict(
>>>     auth_user='user', secret_key='your-secret_key'
>>> )
{
    'signature': 'YlZpLFsjUKBalL4x5trhkeEgqE8=',
    'auth_user': 'user',
    'valid_until': '1378045287.0'
}

If you for some reason prefer a lower level implementation, read the same section in the Advanced usage chapter.

Server side

Validating the signed request data is as simple as follows.

Required imports.

>>> from ska import validate_signed_request_data

Validating the signed request data. Note, that data value is expected to be a dictionary; request.GET is given as an example. It will most likely vary from what’s used in your framework (unless you use Django).

>>> validation_result = validate_signed_request_data(
>>>     data = request.GET, # Note, that ``request.GET`` is given as example.
>>>     secret_key = 'your-secret_key'
>>> )

The validate_signed_request_data produces a ska.SignatureValidationResult object, which holds the following data:

• result (bool): True if data is valid. False otherwise.

• reason (list): List of strings, indicating validation errors. Empty list in case if result is True.

Default name of the (GET) param holding the signature value is signature. If you want it to be different, provide a signature_param argument to validate_signed_request_data function.

Default name of the (GET) param holding the auth_user value is auth_user. If you want it to be different, provide a auth_user_param argument to validate_signed_request_data function.

Default name of the (GET) param holding the valid_until value is valid_until. If you want it to be different, provide a valid_until_param argument to validate_signed_request_data function.

With all customisations, it would look as follows.

>>> validation_result = validate_signed_request_data(
>>>     data = request.GET,
>>>     secret_key = 'your-secret_key',
>>>     signature_param='signature',
>>>     auth_user_param='auth_user', \
>>>     valid_until_param='valid_until'
>>> )

If you for some reason prefer a lower level implementation, read the same section in the Advanced usage chapter.

Client side

Required imports.

>>> from ska import Signature, RequestHelper

Generate a signature.

>>> signature = Signature.generate_signature(
>>>     auth_user = 'user',
>>>     secret_key = 'your-secret-key'
>>>     )

Default lifetime of a signature is 10 minutes (600 seconds). If you want it to be different, provide a lifetime argument to generate_signature method.

>>> signature = Signature.generate_signature(
>>>     auth_user = 'user',
>>>     secret_key = 'your-secret-key',
>>>     lifetime = 120 # Signatre lifetime set to 120 seconds.
>>>     )

Your endpoint operates with certain param names and you need to wrap generated signature params into the URL. In order to have the job done in an easy way, create a request helper. Feed names of the (GET) params to the request helper and let it make a signed endpoint URL for you.

>>> request_helper = RequestHelper(
>>>     signature_param = 'signature',
>>>     auth_user_param = 'auth_user',
>>>     valid_until_param = 'valid_until'
>>> )

Append signature params to the endpoint URL.

>>> signed_url = request_helper.signature_to_url(
>>>     signature = signature,
>>>     endpoint_url = 'http://e.com/api/'
>>> )
http://e.com/api/?valid_until=1378045287.0&auth_user=user&signature=YlZpLFsjUKBalL4x5trhkeEgqE8%3D

Make a request.

>>> import requests
>>> r = requests.get(signed_url)

Server side

Required imports.

>>> from ska import RequestHelper

Create a request helper. Your endpoint operates with certain param names. In order to have the job done in an easy way, we feed those params to the request helper and let it extract data from signed request for us.

>>> request_helper = RequestHelper(
>>>     signature_param = 'signature',
>>>     auth_user_param = 'auth_user',
>>>     valid_until_param = 'valid_until'
>>> )

Validate the request data. Note, that request.GET is given just as an example.

>>> validation_result = request_helper.validate_request_data(
>>>     data = request.GET,
>>>     secret_key = 'your-secret-key'
>>> )

Your implementation further depends on you, but may look as follows.

>>> if validation_result.result:
>>>     # Validated, proceed further
>>>     # ...
>>> else:
>>>     # Validation not passed.
>>>     raise Http404(validation_result.reason)

You can also just validate the signature by calling validate_signature method of the ska.Signature.

>>> Signature.validate_signature(
>>>     signature = 'EBS6ipiqRLa6TY5vxIvZU30FpnM=',
>>>     auth_user = 'user',
>>>     secret_key = 'your-secret-key',
>>>     valid_until = '1377997396.0'
>>>     )