Advanced

This sheet contains slightly advanced concepts, (comparative to the others given in the tutorial).

Extending the Router

The classes on which the framework is based are highly customisable. You can customise them to meet your specific needs.

The Router class actually has a lot. To extend it, you can customise as per your need. For instance, consider that you need a vary fast url-router(C-implementation or Cythonised one) due to some reason.

Then, remember that it must your Router must have a handle method, that accepts a request parameter, and must return an instance of structure.Response. For more info, see :class:willpyre.Router.

Custom error responses

If your application is a JSON based API, then you might not want to have errors in the format of test/html. Or, if you are creating a web app, then you might not want to have a plain, default response. Willpyre gives you that liberty. You have to change the config of :class:App.

from willpyre import Router, App, structure, json
router = Router()
# Do your stuff.

class My404Response(structure.Response404):
        def __init__(self):
        self.status = 404
        self.content_type = "application/json"
        self.body = json.dumps({"error": 404})

app = App(router)
app.config["router_config"]["404Response"] = My404Response()

Startup and Shutdown tasks

You can schedule tasks to be performed on startup and shutdown. Eg:

from willpyre import Router, App
router = Router()
# Some routing..

def startup_task():
        print("Started")
def shutdown_task():
        print("Shutting down.....")
app = App(router)
app.config["startup"] = startup_task
app.config["shutdown"] = shutdown_task

These will be performed when your app starts and when gracefully shuts down. If the process recieves a termination signal(Ctrl +C), then your server, (Hypercorn, Uvicorn or Daphne) will send a shutdown event message which will trigger the shutdown task.