Flask - request time

import time

from flask import Flask, request, g, render_template

app = Flask(__name__)
app.config['DEBUG'] = True

@app.before_request
def before_request():
    g.request_start_time = time.time()
    g.request_time = lambda: "%.5fs" % (time.time() - g.request_start_time)

@app.route("/")
def index():
    t = request.values.get('t', 0)
    time.sleep(float(t)) #just to show it works...
    return render_template("index.html")

if __name__ == "__main__":
    app.run(use_debugger=True, use_reloader=True)

Rendered in {{ g.request_time() }}