Server-Side Scripting/Key-Value Databases/Python (FastAPI)
routers/lesson11.py edit
# This program creates and displays a temperature database
# with options to insert, update, and delete records.
#
# References:
# https://en.wikibooks.org/wiki/Python_Programming
# https://realpython.com/python-redis/
from fastapi import APIRouter, Request
from fastapi.responses import HTMLResponse
from fastapi.templating import Jinja2Templates
import redis as redis_lib
router = APIRouter(prefix="/lesson11")
templates = Jinja2Templates(directory="templates")
# Requires a Redis installation to manage the database.
# Use of a Docker container is recommended.
# See https://en.wikiversity.org/wiki/Docker/Redis .
# If both the FastAPI website and Redis are running in containers,
# use 172.17.0.2 for the Redis host address.
# If the FastAPI website and/or Redis are running locally, use 127.0.0.1
# for the Redis host address.
# HOST = "172.17.0.2"
HOST = "127.0.0.1"
DATABASE = 0
COLLECTION = "countries"
@router.get("/", response_class=HTMLResponse)
async def get_lesson11(request: Request):
try:
result = get_data()
except Exception as exception:
result = exception
return templates.TemplateResponse(
"lesson11.html",
{
"request": request,
"table": result
}
)
@router.post("/", response_class=HTMLResponse)
async def post_lesson11(request: Request):
form = dict(await request.form())
try:
country = form["country"].strip()
temperature = form["temperature"].strip()
if not country_exists(country):
insert_country(country, temperature)
elif temperature != "":
update_country(country, temperature)
else:
delete_country(country)
result = get_data()
except Exception as exception:
result = exception
return templates.TemplateResponse(
"lesson11.html",
{
"request": request,
"table": result
}
)
def get_data():
redis = redis_lib.Redis(host=HOST, db=DATABASE)
result = "<table><tr><th>Country</th>"
result += "<th>Temperature</th></tr>"
countries = redis.keys()
countries.sort()
for country in countries:
temperature = redis.get(country)
result += f"<tr><td>{country.decode()}</td>"
result += f"<td>{temperature.decode()}</td></tr>"
result += "</table>"
return result
def country_exists(country):
redis = redis_lib.Redis(host=HOST, db=DATABASE)
return bool(redis.exists(country))
def insert_country(country, temperature):
redis = redis_lib.Redis(host=HOST, db=DATABASE)
redis.set(country, temperature)
def update_country(country, temperature):
redis = redis_lib.Redis(host=HOST, db=DATABASE)
redis.set(country, temperature)
def delete_country(country):
redis = redis_lib.Redis(host=HOST, db=DATABASE)
redis.delete(country)
templates/lesson11.html edit
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Lesson 11</title>
<link rel="stylesheet" href="{{url_for('static', path='/styles.css')}}">
</head>
<body>
<h1>Temperature Data Entry</h1>
<p>Enter country and temperature. Enter again to update.</p>
<p>Enter country without temperature to delete.</p>
<form method="POST">
<p><label for="country">Country:</label>
<input type="text" id="country" name="country" required>
</p>
<p><label for="stop">Temperature:</label>
<input type="text" id="temperature" name="temperature">
</p>
<p><input type="submit" name="submit" value="Submit"></p>
</form>
<hr>
{{table|safe}}
</body>
</html>
Try It edit
See Server-Side Scripting/Routes and Templates/Python (FastAPI) to create a test environment.