MyPy types for WSGI applications

Overview

WSGI Types for Python

This is an attempt to bring some type safety to WSGI applications using Python's new typing features (TypedDicts, Protocols). It seems to work OK but may still be full of gaps, holes, bugs, missteps, etc. It helped bring a lot of extra safety to a couple of places that really needed it though, and seemed to remain quite stable for a couple of months.

This is implemented as a Python module, rather than MyPy stubs, as it represents a protocol things can satisfy rather than a set of types for something concrete.

This package came together during an exploration documented here: https://github.com/python/mypy/issues/7654

Define a callable application as a class:

import wsgitypes

class MyApplication(wsgitypes.Application):
    def __call__(
        self,
        environ: wsgitypes.Environ,
        start_response: wsgitypes.StartResponse,
    ) -> wsgitypes.Response:
        my_header = environ.get("REQUEST_METHOD", "")
        return []

Environ should be type-safe:

class MyApplication(wsgitypes.Application):
    def __call__(
        self,
        environ: wsgitypes.Environ,
        start_response: wsgitypes.StartResponse,
    ) -> wsgitypes.Response:
        environ["wsgi.input"] # Good
        environ["wsgi.unpot"] # BORK! MyPy will catch this.
        return []

You can define your own extensions to Environ using TypedDict inheritance, like so:

class MyEnviron(wsgitypes.Environ):
    HTTP_X_MY_HEADER: t.Optional[str]

class MyApplication(wsgitypes.Application):
    def __call__(
        self,
        environ: MyEnviron,
        start_response: wsgitypes.StartResponse,
    ) -> wsgitypes.Response:
        environ = typing.cast(MyEnviron, environ)
        environ.get("HTTP_X_MY_HEADER") # Good
        return []

Note that you need to use typing.cast to convert the incoming Environ to your derived version. An attempt was made to use a type param for Environ, but it wasn't viable (even with GVR helping!): https://github.com/python/mypy/issues/7654

Owner
Blake Williams
I code for fun. I have been known to code for food. I typically work with Go, TypeScript, Python or C. I enjoy Go a lot. I have worked with lots of other stuff.
Blake Williams
Easy saving and switching between multiple KDE configurations.

Konfsave Konfsave is a config manager. That is, it allows you to save, back up, and easily switch between different (per-user) system configurations.

42 Sep 25, 2022
Flashcards - A flash card application with 2 optional command line arguments

Flashcards A flash card application with 2 optional command line arguments impor

Özgür Yildirim 2 Jul 15, 2022
PEP-484 typing stubs for SQLAlchemy 1.4 and SQLAlchemy 2.0

SQLAlchemy 2 Stubs These are PEP-484 typing stubs for SQLAlchemy 1.4 and 2.0. They are released concurrently along with a Mypy extension which is desi

SQLAlchemy 139 Dec 30, 2022
Flake8 extension to provide force-check option

flake8-force Flake8 extension to provide force-check option. When this option is enabled, flake8 performs all checks even if the target file cannot be

Kenichi Maehashi 9 Oct 29, 2022
:sparkles: Surface lint errors during code review

✨ Linty Fresh ✨ Keep your codebase sparkly clean with the power of LINT! Linty Fresh parses lint errors and report them back to GitHub as comments on

Lyft 183 Dec 18, 2022
A Pylint plugin to analyze Flask applications.

pylint-flask About pylint-flask is Pylint plugin for improving code analysis when editing code using Flask. Inspired by pylint-django. Problems pylint

Joe Schafer 62 Sep 18, 2022
Design by contract for Python. Write bug-free code. Add a few decorators, get static analysis and tests for free.

A Python library for design by contract (DbC) and checking values, exceptions, and side-effects. In a nutshell, deal empowers you to write bug-free co

Life4 473 Dec 28, 2022
Flake8 Type Annotation Checking

flake8-annotations flake8-annotations is a plugin for Flake8 that detects the absence of PEP 3107-style function annotations and PEP 484-style type co

S. Co1 118 Jan 05, 2023
Collection of awesome Python types, stubs, plugins, and tools to work with them.

Awesome Python Typing Collection of awesome Python types, stubs, plugins, and tools to work with them. Contents Static type checkers Dynamic type chec

TypedDjango 1.2k Jan 04, 2023
Silence mypy by adding or removing code comments

mypy-silent Automatically add or remove # type: ignore commends to silence mypy. Inspired by pylint-silent Why? Imagine you want to add type check for

Wu Haotian 8 Nov 30, 2022
Type annotations builder for boto3 compatible with VSCode, PyCharm, Emacs, Sublime Text, pyright and mypy.

mypy_boto3_builder Type annotations builder for boto3-stubs project. Compatible with VSCode, PyCharm, Emacs, Sublime Text, mypy, pyright and other too

Vlad Emelianov 2 Dec 05, 2022
open source tools to generate mypy stubs from protobufs

mypy-protobuf: Generate mypy stub files from protobuf specs We just released a new major release mypy-protobuf 2. on 02/02/2021! It includes some back

Dropbox 527 Jan 03, 2023
A plugin for Flake8 that checks pandas code

pandas-vet pandas-vet is a plugin for flake8 that provides opinionated linting for pandas code. It began as a project during the PyCascades 2019 sprin

Jacob Deppen 146 Dec 28, 2022
Rust like Option and Result types in Python

Option Rust-like Option and Result types in Python, slotted and fully typed. An Option type represents an optional value, every Option is either Some

45 Dec 13, 2022
Flake8 plugin for managing type-checking imports & forward references

flake8-type-checking Lets you know which imports to put in type-checking blocks. For the imports you've already defined inside type-checking blocks, i

snok 67 Dec 16, 2022
Code audit tool for python.

Pylama Code audit tool for Python and JavaScript. Pylama wraps these tools: pycodestyle (formerly pep8) © 2012-2013, Florent Xicluna; pydocstyle (form

Kirill Klenov 967 Jan 07, 2023
The mypy playground. Try mypy with your web browser.

mypy-playground The mypy playground provides Web UI to run mypy in the sandbox: Features Web UI and sandbox for running mypy eas

Yusuke Miyazaki 57 Jan 02, 2023
Mypy stubs for the PyQt5 framework

Mypy stubs for the PyQt5 framework This repository holds the stubs of the PyQt5 framework. It uses the stub files that are produced during compilation

62 Nov 22, 2022
It's not just a linter that annoys you!

README for Pylint - https://pylint.pycqa.org/ Professional support for pylint is available as part of the Tidelift Subscription. Tidelift gives softwa

Python Code Quality Authority 4.4k Jan 04, 2023
Mypy stubs, i.e., type information, for numpy, pandas and matplotlib

Mypy type stubs for NumPy, pandas, and Matplotlib This is a PEP-561-compliant stub-only package which provides type information for matplotlib, numpy

Predictive Analytics Lab 194 Dec 19, 2022