Documentation

Overview

md.http.server.lifecycle component provides psr.http.server contract implementation to build generic high-level web-application.

Implementation defines the Mediator architecture design of high-level application how request will be handled.

Application does not manage low-level th

Consider to look for md.http.server component that provides low-level application.

Architecture overview

Lifecycle overview

Install

pip install md.http.server.lifecycle --index-url https://source.md.land/python/

Usage

import psr.http.message

import md.event
import md.log

import md.http.server.lifecycle


class HandleRequest:
    def on_request(self, event: md.http.server.lifecycle.RequestEvent) -> None:
        # todo implement your logic here
        #      for example, match route, invoke and get response ...

        # set response in request event 
        event.response = ...

        assert isinstance(event.response, psr.http.message.ResponseInterface)

class HandleResponse:
    def on_response(self, event: md.http.server.lifecycle.ResponseEvent) -> None:
        # todo modify response
        #      for example, convert string to response, 
        #      or set 404 response if there is no response
        event.response = ...

        assert isinstance(event.response, psr.http.message.ResponseInterface)


if __name__ == '__main__':
    # arrange
    event_dispatcher = md.event.Dispatcher()
    logger = md.log.Logger(
        keep_list=[md.log.KeepStream.from_file(filename_list=['/dev/stderr'])]
    )

    application = md.http.server.lifecycle.Application(
        event_dispatcher=event_dispatcher,
        logger=logger,
    )

    # act
    hrq = HandleRequest()
    hrs = HandleResponse()
    event_dispatcher.subscribe(event=md.http.server.lifecycle.RequestEvent, handler=hrq.on_request)
    event_dispatcher.subscribe(event=md.http.server.lifecycle.ResponseEvent, handler=hrs.on_response)

    request = ...
    assert isinstance(request, psr.http.message.RequestInterface)
    response = application.handle(request=request)

Request event

md.http.server.lifecycle.RequestEvent is an event object which is dispatched on application request processing start.

Event object contains request and response attributes:

• request: psr.http.message.RequestInterface represents original request object
• response: psr.http.message.ResponseInterface | typing.Any = None response is to be returned by an application. When response is type of Any, expected that there is some ResponseEvent event handler which finally will convert it to an instance of psr.http.message.ResponseInterface.

Each handler may handle RequestEvent without set response value into an event object, but when it is set, dispatcher stop dispatch cycle and returns control back to an application.

Response event

md.http.server.lifecycle.ResponseEvent is an event object which is dispatched after request event dispatch finished.

Event object contains request and response attributes:

Designed to ... or override response model.