"""Example web app that connects to PostgreSQL.""" from io import StringIO import psycopg from flask import Flask app = Flask(__name__) con = psycopg.connect( host="data.cs.jmu.edu", user="demo", password="demo", dbname="world" ) cur = con.cursor() @app.route("/") def hello_world(): return "

Hello, World!

" @app.route("/country/") def country_info(code: str): _ = cur.execute( "SELECT name, continent, region, population FROM country WHERE code = %s", (code.upper(),), ) row = cur.fetchone() if not row: return "

Country not found

" name, cont, reg, pop = row out = StringIO() _ = out.write( f"

{name} is in {cont} in the {reg} region.

" ) _ = out.write( f"

{name}'s population {pop:,d}.

" ) return out.getvalue() @app.route("/codes") def multi_country(): _ = cur.execute("SELECT name, code population FROM country") return f"" if __name__ == "__main__": app.run(debug=True)