Python Connect Business Transaction Middleware

Provides simple request-response style middleware for business transactions.

Installation

The easiest way to install the Connect Business Transaction Middleware library is to get the latest version from PyPI:

# using poetry
poetry add rndi-connect-business-transaction-middleware
# using pip
pip install rndi-connect-business-transaction-middleware

Usage

Creating and using a business transaction middleware is very easy, you just need to declare a middleware:

from typing import Optional

from connect.eaas.core.responses import BackgroundResponse
from rndi.connect.business_transactions.contracts import FnBackgroundExecution


def middleware_sample(request: dict, nxt: Optional[FnBackgroundExecution] = None) -> BackgroundResponse:
    print('Sample Before')
    response = nxt(request)
    print('Sample After')
    return response

The signature of a middle must be the following:

Middleware = Callable[[dict, Optional[FnBackgroundExecution]], TBackgroundResponse]

A middleware must accept a dictionary, commonly the Connect request dictionary, and an optional FnBackgroundExecution, which is the next middleware or the actual transaction to be executed. The return type must be a valid BackgroundResponse.

Once we have our middleware ready we can use the make_middleware_callstack to wrap the transaction with our middlewares, as you can see as follows:

from rndi.connect.business_transactions.adapters import prepare

# Prepare the selected transaction.
transaction = prepare(SomeTransaction())

# Instantiate the required middlewares.
middlewares = [
    middleware_sample
]

# Make the middleware callstack.
transaction = make_middleware_callstack(middlewares, transaction)

# Transaction Execution.
response = transaction(request)