A simple, clean and less dependant client to handle payments through RedSys platform (previously known as Sermepa) using the two types of connection defined by the platform: direct connection (or webservice) and redirect connection or (secure method).

The purpose of this library is to provide a normalized interface between RedSys and other applications.

About `RedirectClient`

Although redirect connection depends on a webserver to resolve the communication step, the RedirectClient provided in this library does not assume any kind of procedure to resolve that step; it simply prepares the necessary parameters to make a request and handle the corresponding response parameters. That's what less dependant means.

If you intend to use this library with django, take a look at <https://github.com/ddiazpinto/django-redsys>. Django-redsys uses this library and extends it to resolve all the communication step. Unfortunately, it is not documented at all but if you need some help, let me know submitting an issue.

from decimal import Decimal as D, ROUND_HALF_UP
from redsys import currencies, languages, parameters, transactions
from redsys.client import RedirectClient

secret_key = u'123456789abcdef'
sandbox = False
client = RedirectClient(secret_key, sandbox)

request = client.create_request()

request.merchant_code = u'100000001'
request.terminal = u'1'
request.transaction_type = transactions.STANDARD_PAYMENT
request.currency = currencies.EUR
request.order = u'000000001'
# The amount must be defined as decimal and pre-formated with only two decimals
request.amount = D('10.56489').quantize(D('.01'), ROUND_HALF_UP)
request.merchant_data = 'merchant data for tracking purpose like order_id, session_key, ...'
request.merchant_name = "Example Commerce"
request.titular = "Example Ltd."
request.product_description = "Products of Example Commerce"
request.merchant_url = "https://example.com/redsys/response"

This method returns a dict with the necessary post parameters needed during the communication step.

args = client.prepare_request(request)

Redirect the user-agent to the corresponding RedSys's endpoint using the post parameters given in the previous step.

After the payment process is finish, RedSys will respond making a request to the merchant_url defined in the step 3.

Create the response object using the received parameters from RedSys. The method create_response() throws a ValueError in case the received signature is not equal to the one calculated using the given merchant_parameters. This normally means that the response is not comming from RedSys or that has been compromised.

signature = "YqFenHc2HpB273l8c995...."
merchant_parameters = "AndvIh66VZdkC5TG3nYL5j4XfCnFFbo3VkOu9TAeTs58fxddgc..."
signature_version = "HMAC_SHA256_V1"
response = client.create_response(signature, merchant_parameters, signature_version)
if response.is_paid():
    # Do the corresponding actions after a successful payment
else:
    # Do the corresponding actions after a failed payment
    raise Exception(response.response, response.message)

Methods for checking the response:

According to the RedSys documentation:

• response.is_paid(): Returns True if the response code is between 0 and 99 (both included).
• response.is_canceled(): Returns True if the response code is 400.
• response.is_refunded(): Returns True if the response code is 900.
• response.is_authorized(): Returns True if the response is paid, refunded or canceled.

Also, you can directly access the code or the message defined in RedSys documentation using response.response_code or response.response_message.

This connection method is not implemented yet.

Please, feel free to send any contribution that maintains the less dependant philosophy.