oam/knowledge base/python.md

Python

1. TL,DR
2. Web servers
   1. Flask
   2. WSGI server
3. Further readings

TL,DR

# String formatting with f-strings.
f"Hello, {name}. You are {age}."
F"{name.lower()} is funny."

# Make elements in a list unique.
# Keep the resulting list mutable.
unique_list = list(set(redundant_list))

Web servers

Flask

• request.args gets query arguments
• request.form gets POST arguments

from flask import request, jsonify

@app.route('/get/questions/', methods=['GET', 'POST','DELETE', 'PATCH'])
def question():
    if request.method == 'GET':
        start = request.args.get('start', default=0, type=int)
        limit_url = request.args.get('limit', default=20, type=int)
        data = [doc for doc in questions]
        return jsonify(
            isError = False,
            message = "Success",
            statusCode = 200,
            data= data
        ), 200
    if request.method == 'POST':
        question = request.form.get('question')
        topics = request.form.get('topics')
        return jsonify(
            isError = True,
            message = "Conflict",
            statusCode = 409,
            data = data
        ), 409

WSGI server

You can use waitress:

from flask import Flask

app = Flask(__name__)

@app.route("/")
def index():
    return "<h1>Hello!</h1>"

if __name__ == "__main__":
    from waitress import serve
    serve(app, host="0.0.0.0", port=8080)

pip install flask waitress
python hello.py

Further readings

• PIP
• How To Update All Python Packages
• invl/pip-autoremove
• Data types
• F-strings
• How to filter list elements in Python
• Logging
• Flask at first run: do not use the development server in a production environment
• Flask example with POST
• Multi-value query parameters with Flask
• *args and **kwargs in Python
• An intro to threading in Python
• ThreadPoolExecutor in Python: the complete guide