ska Package¶

ska Package¶

class ska.__init__.Signature(signature, auth_user, valid_until)[source]¶

Bases: object

Signature generation and validation based on symmetric keys.

Parameters:	signature (str) – auth_user (str) – valid_until (float|str) –

auth_user¶

static datetime_to_timestamp(dt)[source]¶

Human readable datetime according to the format specified in TIMESTAMP_FORMAT.

Parameters:	dt (datetime.datetime) –
Return str:

static datetime_to_unix_timestamp(dt)[source]¶

Converts datetime.datetime to Unix timestamp.

Parameters:	dt (datetime.datetime) –
Return float:	Unix timestamp.

classmethod generate_signature(auth_user, secret_key, valid_until=None, lifetime=600)[source]¶

Generates the signature. If timestamp is given, the signature is created using the given timestamp. Otherwise current time is used.

Parameters:	auth_user (str) – secret_key (str) – valid_until (float|str) – Unix timestamp, valid until. lifetime (int) – Lifetime of the signature in seconds.
Return str:
Example :

>>> sig = Signature.generate_signature('user', 'your-secret-key')
EBS6ipiqRLa6TY5vxIvZU30FpnM=

classmethod get_base(auth_user, timestamp)[source]¶

Add something here so that timestamp to signature conversion is not that obvious.

is_expired()[source]¶

Checks if current signature is expired. Returns True if signature is expired and False otherwise.

Return bool:
Example :

>>> sig = Signature.generate_signature('user', 'your-secret-key') # Generating the signature
>>> sig.is_expired()
False

static make_secret_key(secret_key)[source]¶

The secret key how its’ supposed to be used in generate signature.

Parameters:	secret_key (str) –
Return str:

signature¶

classmethod timestamp_to_date(timestamp, fail_silently=True)[source]¶

Converts the given timestamp to date. If fail_silently is set to False, raises exceptions if timestamp is not valid timestamp (according to the format we have specified in the TIMESTAMP_FORMAT). Mainly used internally.

Parameters:	timestamp (str) – fail_silently (bool) –
Return str:

classmethod unix_timestamp_to_date(timestamp, fail_silently=True)[source]¶

Converts the given Unix timestamp to date. If fail_silently is set to False, raises exceptions if timestamp is not valid timestamp.

Parameters:	timestamp (float|str) – UNIX timestamp. Parsable to float. fail_silently (bool) –
Return str:

valid_until¶

classmethod validate_signature(signature, auth_user, secret_key, valid_until, return_object=False)[source]¶

Validates the signature.

Parameters:	signature (str) – auth_user (str) – secret_key (str) – valid_until (float|str) – Unix timestamp. return_object (bool) – If set to True, an instance of SignatureValidationResult is returned.
Return bool:
Example :

>>> Signature.validate_signature(
    'EBS6ipiqRLa6TY5vxIvZU30FpnM=',
    'user',
    'your-secret-key',
    '1377997396.0'
    )
False

class ska.__init__.RequestHelper(signature_param, auth_user_param, valid_until_param)[source]¶

Bases: object

Request helper for easy put/extract of signature params from URLs.

signature_to_dict(signature)[source]¶

Puts signature into a dictionary, which can later on be used to send when sending (POST) requests to the server.

Parameters:	signature (ska.Signature) –
Return dict:
Example :

Required imports.

>>> from ska import Signature, RequestHelper

Generate signature.

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

Create a request helper.

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

Appending signature params to the endpoint URL.

>>> signed_dict = request_helper.signature_to_dict(
>>>     signature = signature
>>> )
{
    'signature': 'YlZpLFsjUKBalL4x5trhkeEgqE8=',
    'auth_user': 'user',
    'valid_until': '1378045287.0'
}

signature_to_url(signature, endpoint_url='', suffix='?')[source]¶

URL encodes the signature params.

Parameters:	signature (ska.Signature) – endpoint_url (str) – suffix (str) – Suffix to add after the endpoint_url and before the appended signature params.
Return str:
Example :

Required imports.

>>> from ska import Signature, RequestHelper

Generate signature.

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

Create a request helper.

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

Appending signature params to the endpoint URL.

>>> 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

validate_request_data(data, secret_key)[source]¶

Validates the request data.

Parameters:	data (dict) – secret_key (str) –
Return ska.SignatureValidationResult:
Example :

If your imaginary HttpRequest object has GET property (dict), then you would validate the request data as follows.

Create a RequestHelper object with param names expected.

Required imports.

>>> from ska import RequestHelper

Create a request helper.

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

Validate the request data.

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

ska.__init__.sign_url(auth_user, secret_key, valid_until=None, lifetime=600, url='', suffix='?', signature_param='signature', auth_user_param='auth_user', valid_until_param='valid_until')[source]¶

Signs the URL.

Parameters:	auth_user (str) – Username of the user making the request. secret_key (str) – The shared secret key. valid_until (float|str) – Unix timestamp. If not given, generated automatically (now + lifetime). lifetime (int) – Signature lifetime in seconds. url (str) – URL to be signed. suffix (str) – Suffix to add after the endpoint_url and before the appended signature params. signature_param (str) – Name of the GET param name which would hold the generated signature value. auth_user_param (str) – Name of the GET param name which would hold the auth_user value. valid_until_param (str) – Name of the GET param name which would hold the valid_until value.
Return str:
Example :

Required imports.

>>> from ska import sign_url

Producing a signed URL.

>>> signed_url = sign_url(
>>>     auth_user='user', secret_key='your-secret_key', lifetime=120,     >>>     url='http://e.com/api/', signature_param=DEFAULT_SIGNATURE_PARAM,
>>>     auth_user_param=DEFAULT_AUTH_USER_PARAM, valid_until_param=DEFAULT_VALID_UNTIL_PARAM
>>> )
http://e.com/api/?valid_until=1378045287.0&auth_user=user&signature=YlZpLFsjUKBalL4x5trhkeEgqE8%3D

defaults Module¶

Application defaults.

• SIGNATURE_LIFETIME (int): Signature lifetime in seconds. Default value is 600 (seconds).
• DEFAULT_SIGNATURE_PARAM (str): Default name of the GET param holding the generated signature value. Default value is signature.
• DEFAULT_AUTH_USER_PARAM (str): Default name of the GET param holding the auth_user value. Default value is auth_user.
• DEFAULT_VALID_UNTIL_PARAM (str): Default name of the GET param holding the valid_until value. Default value is valid_until.
• DEFAULT_URL_SUFFIX (str): Suffix to add after the endpoint_url and before the appended signature params.

generate_signed_url Module¶

ska.generate_signed_url.main()[source]¶

Prints signed URL to console.

Example :

$ python src/ska/generate_signature.py -au user -sk test

Subpackages¶