proxyctx

ProxyCTX is a handy utility library that empowers developers to establish a global context accessible from anywhere within their application. Its creation was inspired by Flask, a popular web framework. Under the hood, ProxyCTX leverages the Python standard module contextvars.

The library consists of just two key components:

• Proxy: Inspired by Werkzeug's LocalProxy class (werkzeug.local)
• Context: Inspired by Flask's AppContext class (flask.ctx)

Flask Example

In Flask, when defining a route, the corresponding method does not receive any parameters representing the incoming request. Instead, you can import a global variable called request, which conveniently holds information about the incoming request. Here's an example code snippet illustrating this:

from flask import Flask, request

app = Flask(__name__)

@app.route("/")
def index():
    print(request.method)

It's worth noting that request is not the only global variable available in Flask. You can explore the flask.globals module, which encompasses all the global variables provided by Flask.

Usage

To install the library use the following command:

pip install proxyctx

Proxy

from contextvars import ContextVar
from proxyctx import Proxy

class Greet:
    def __init__(self, message: str = None):
        self.message = message

    def greet(self, name: str):
        if self.message is None:
            print(f"Hello {name} !")
        else:
            print(f"Hello {name}, {self.message}")

ctx: ContextVar["Greet"] = ContextVar("ctx")
current_greet: "Greet" = Proxy(ctx)
current_message: str = Proxy(ctx, lambda obj: obj.message)

ctx.set(Greet("how are you ?"))
print(current_message) # "how are you ?"
current_greet.greet("Lucino772") # "Hello Lucino772, how are you ?"

ctx.set(Greet("have a nice day !"))
print(current_message) # "have a nice day !"
current_greet.greet("Lucino772") # "Hello Lucino772, have a nice day !"

Context

from contextvars import ContextVar
from proxyctx import Proxy, Context

ctx: ContextVar["GreetContext"] = ContextVar("ctx")
current_greet: "Greet" = Proxy(ctx, lambda obj: obj.greet)

class Greet:
    def __init__(self, message: str = None):
        self.message = message

    def greet(self, name: str):
        if self.message is None:
            print(f"Hello {name} !")
        else:
            print(f"Hello {name}, {self.message}")

    def greet_context(self):
        return GreetContext(self)

class GreetContext(Context):
    def __init__(self, greet: "Greet"):
        super().__init__(ctx)
        self.greet = greet

with Greet("how are you ?").greet_context():
    current_greet.greet("Lucino772") # "Hello Lucino772, how are you ?"
    with Greet("have a nice day !").greet_context():
        current_greet.greet("Lucino772") # "Hello Lucino772, have a nice day !"
    current_greet.greet("Lucino772") # "Hello Lucino772, how are you ?"

Licence

This project uses a MIT Licence view