Server-Side Scripting/Arrays/Python (FastAPI)
routers/lesson6.py
edit# This program reads a user-selected text file of countries
# and Celsius temperatures. It displays the data in Celsius
# and Fahrenheit sorted in descending order by temperature.
#
# File format:
# Country,MaximumTemperature
# Bulgaria,45.2 °C
# Canada,45 °C
#
# References:
# https://www.mathsisfun.com/temperature-conversion.html
# https://fastapi.tiangolo.com/tutorial/request-files/
from fastapi import APIRouter, Request, File, UploadFile
from fastapi.responses import HTMLResponse
from fastapi.templating import Jinja2Templates
router = APIRouter(prefix="/lesson6")
templates = Jinja2Templates(directory="templates")
@router.get("/", response_class=HTMLResponse)
async def get_lesson6(request: Request):
return templates.TemplateResponse(
"lesson6.html",
{
"request": request,
"table": ""
}
)
@router.post("/", response_class=HTMLResponse)
async def post_lesson6(request: Request, file: UploadFile = File(...)):
try:
result = await process_file(file)
except Exception as exception:
result = exception
return templates.TemplateResponse(
"lesson6.html",
{
"request": request,
"table": result
}
)
async def process_file(file):
if not file:
return "No file selected"
text = await file.read()
text = text.decode()
lines = text.strip().split("\n")
if "country," in lines[0].lower():
lines.pop(0) # Remove heading line
table = []
for line in lines:
try:
array = process_line(line)
table.append(array)
except ValueError as exception:
return str(exception)
table.sort(key=lambda x:x[1], reverse=True)
result = f"<h2>{file.filename}</h2>"
result += format_table(table)
return result
def process_line(line):
array = line.split(",")
if len(array) != 2:
raise ValueError("Invalid file format")
celsius = array[1]
index = celsius.find(" °C")
if index < 0:
raise ValueError("Invalid file format")
try:
celsius = float(celsius[0:index])
except:
raise ValueError("Invalid temperature data")
array[1] = celsius
fahrenheit = celsius * 9 / 5 + 32
array.append(fahrenheit)
return array
def format_table(table):
result = "<table><tr><th>Country</th>"
result += "<th>Celsius</th>"
result += "<th>Fahrenheit</th></tr>"
for row in table:
result += f"<tr><td>{row[0]}</td>"
result += f"<td>{row[1]:.1f}° C</td>"
result += f"<td>{row[2]:.1f}° F</td></tr>"
result += "</table>"
return result
templates/lesson6.html
edit<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Lesson 6</title>
<link rel="stylesheet" href="{{url_for('static', path='/styles.css')}}">
<style>
p {
min-height: 1em;
}
</style>
</head>
<body>
<h1>Temperature Conversion</h1>
<p>Select a file of Celsius temperatures for conversion:</p>
<form method="POST" enctype="multipart/form-data">
<input type="file" id="file" name="file">
<input type="submit">
</form>
{{table|safe}}
</body>
</html>
Try It
editSee Server-Side Scripting/Routes and Templates/Python (FastAPI) to create a test environment.