Python these days

Install python §

brew install python

Install poetry §

// Ubuntu
curl -sSL https://install.python-poetry.org | python3 -
 
// OSX
curl -sSL https://install.python-poetry.org | sed 's/symlinks=False/symlinks=True/' | python3 -

Alias python3 to python §

On macOS, there are several ways to alias python3 to python. Here are the best options, each with its own pros and cons:

1. Using .bashrc or .zshrc (Recommended for permanent alias):

• Edit your shell configuration file:

  • Open Terminal and run nano ~/.bashrc (for Bash) or nano ~/.zshrc (for Zsh).

• Add the following line:

alias python="python3"

• Save the file and reload your shell configuration:

  • source ~/.bashrc (for Bash) or source ~/.zshrc (for Zsh).

Quick Tips

echo 'alias python="python3"' >> ~/.bashrc

How to solve Pylance 'missing imports' in vscode

In my case, the fastest solution when imports are not missing is to launch vscode from the virtual environment. Basically, activate the venv as always, and then code .

Project initialize §

create project folder §

mkdir loudy-webserver

cd loudy-webserver/

poetry init §

poetry init

poetry add Django

poetry add djangorestframework

entering virtual environment §

poetry shell

folder of config §

poetry run django-admin startproject config .

folder of apps §

mkdir apps

cd apps

mkdir film

python manage.py startapp film apps/ film

Tips

If you want to structure project like this way, you need to added this line into settings.py sys.path.insert(0, os.path.join(BASE_DIR, 'apps'))

後記

最後還是莫名會遇到 naming confilcts 的問題，最快的解決方法還是在根目錄(與manage.py同層)， 直接python manage.py [app name] 再將資料夾搬進apps資料夾下。

running §

python manage.py makemigrations

python manage.py migrate

python manage.py runserver 0.0.0.0:8000

DRF Integrate Swagger doc §

poetry add drf-spectacular

in config/settings.py add

REST_FRAMEWORK = {
   "DEFAULT_SCHEMA_CLASS": "drf_spectacular.openapi.AutoSchema",
}
...
 
SPECTACULAR_SETTINGS = {
    "TITLE": "DRF Todo List",
    "DESCRIPTION": "This is a todo list for DRF practice.",
    "VERSION": "1.0.0",
    "SERVE_INCLUDE_SCHEMA": False,
}

in config/urls.py add

from drf_spectacular import views as doc_views
 
urlpatterns = [
...
 
path("api/schema.json", doc_views.SpectacularJSONAPIView.as_view(), name="schema"),
 
path("api/swagger/", doc_views.SpectacularSwaggerView.as_view()),
 
path("api/redoc/", doc_views.SpectacularRedocView.as_view()),
 
]

Sqlite GUI §

While sqlite itself does not provide any network endpoints you can use a web gui such as sqlite-web.

Assuming you have python installed you can install it with

pip install sqlite-web

Once installed, start the web interface with:

sqlite_web my_database.db

By default it runs on http://127.0.0.1:8080/ ie is only accesible from the localhost.

To make it visible on your LAN/WAN start it with:

sqlite_web --host 0.0.0.0 my_database.db

While running with --host 0.0.0.0 might be fine on your own home or corporate network, it’s a really bad idea to do it on a public host (even though the app allows setting a password). For remote access on a public host you will probably want to use the default binding on 127.0.0.1 and then forward the port over ssh or a vpn tunnel.

Setup python-redis §

poetry add channels_redis

docker run --rm -p 6379:6379 redis:7

# django_channels/settings.py
# Channels
# 新增 channel layers 設定
CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels_redis.core.RedisChannelLayer",
        "CONFIG": {
            "hosts": [("127.0.0.1", 6379)],
        },
    },
}

Django cors §

poetry add django-cors-headers

在settings.py的INSTALLED_APPS加上corsheaders:

INSTALLED_APPS = (
    ...
    'corsheaders',
    ...
)

在MIDDLEWARE_CLASSES加上:

MIDDLEWARE_CLASSES = (
    ...
    'corsheaders.middleware.CorsMiddleware',
    'django.middleware.common.CommonMiddleware',
    ...
)

Note

如果設定了USE_ETAGS=True,那麼CordMiddleware必須要在Django CommonMiddleware之前, 否則CORS headers就會因304 not-modified responses被遺失了.

設定方式是在settings.py中設定如下:

CORS_ORIGIN_ALLOW_ALL = True # 允許所有跨站請求, 且whitelist不會被使用

CORS_ORIGIN_ALLOW_ALL的預設值是False, 我們可以設定white list:

CORS_ORIGIN_WHITELIST = (
    'localhost:9000', # 本機的不同port
    'mysite.com',
    ...
)

WTF is *Args and **Kwargs §

https://www.youtube.com/watch?v=4jBJhCaNrWU

Conclusion §

*args handled tuple or list (Iterable) **kwargs handled dictionary(key & value pairs)