Generic Middleware Pipeline

This is a generic middleware pipeline that can be used to create a pipeline of middleware functions that can be used to process a request and response.

It is purely an example project.

Installation

This project is managed with poetry

poetry install # install pytest

poetry run pytest # run tests

About the middleware pipeline

Each middleware function will receive three parameters:

• req: The request object, which may be mutated by the middleware function
• res: The response object, which may be mutated by the middleware function
• next: The next middleware function in the pipeline

If the middleware function does not call next(), the pipeline will not continue.

Here is an example of how to use the middleware pipeline:

from generic_middleware_pipeline import run_middleware_pipeline

def middleware1(req, res, next):
    if req['some_condition']:
        res['some_value'] = 'some_value'
        # in this case we will allow the pipeline to continue
        next()
    else:
        # in this case we will not allow the pipeline to continue
        res['some_value'] = 'some_other_value'

def middleware2(req, res, next):
    # Do something, and then allow the pipeline to continue
    res['mutated_by_m2'] = True
    next()

# note that we _mutate_ the `req` and `res` that are passed in.
# this method of using the response is just for convenience.
req, res = run_middleware_pipeline({}, {}, [
    middleware1,
    middleware2
])

You can easily create a middleware that itself calls a pipeline of middleware functions.

from generic_middleware_pipeline import run_middleware_pipeline

def child1(req, res, next):
    # Do something
    next()

def child2(req, res, next):
    # Do something
    next()

def my_child_pipeline_middleware(req, res, next):
    run_middleware_pipeline(req, res, [
        child_1,
        child_2
    ])