Flask Tutorial - 404 Not Found

Question

I just finished the basic Flask tutorial ( here ), and although I followed all the steps when I try

python flaskr.py

what i get is 404 Not Found error saying

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

here is the code inside the file

 import os import sqlite3 from flask import Flask, request, session, g, redirect, url_for, abort, render_template, flash #create app app = Flask(__name__) app.config.from_object(__name__) #load default conf and override config from an env var app.config.update(dict( DATABASE=os.path.join(app.root_path, 'flaskr.db'), DEBUG=True, SECRET_KEY = 'dev key', USERNAME = 'admin', PASSWORD = 'admin' )) app.config.from_envvar('FLASKR_SETTINGS', silent=True) def connect_db(): """connect to the specific db""" rv = sqlite3.connect(app.config['DATABASE']) rv.row_factory = sqlite3.Row return rv if __name__== '__main__': app.run() def get_db(): """opens a new db connection if there is none yet for the cyrrent app""" if not hasattr(g, 'sqlite_db'): g.sqlite_db = connect_db() return g.sqlite_db @app.teardown_appcontext def close_db(error): """closes the db again at the end of the request.""" if hasattr(g, 'sqlite_db'): g.sqlite_db.close() def init_db(): with app.app_context(): db = get_db() with app.open_resource('schema.sql', mode='r') as f: db.cursor().executescript(f.read()) db.commit() @app.route('/') def show_entries(): db_get_db() cur = db.execute('select title, text from entries order by id desc') entries = cur.fetchall() return render_template('show_entries.html', entries=entries) @app.route('/add', methods=['POST']) def add_entry(): if not session.get('logged_in'): abort(401) db = get_db() db.execute('insert into entries (title, text) values (?,?)', [request.form['title'], request.form['text']]) db.commit() flash('New entry was successfully posted') return redirect(url_for('show_entries')) @app.route('/login', methods=['GET', 'POST']) def login(): error = None if request.method == 'POST': if request.form['username'] != app.config['USERNAME']: error = 'Invalid username' elif request.form['password'] != app.config['PASSWORD']: error = 'Invalid password' else: session['logged_in'] = True flash('You were logged in') return redirect(url_for('show_entries')) return render_template('login.html', error=error) @app.route('/logout') def logout(): session.pop('logged_in', None) flash('You were logged out') return redirect(url_for('show_entries')) 

This is the console message I get (plus 3 attempts to refresh the page):

 user@user :~/Flask/flaskr$ python flaskr.py * Running on http://127.0.0.1:5000/ * Restarting with reloader 127.0.0.1 - - [19/Aug/2014 15:23:40] "GET / HTTP/1.1" 404 - 127.0.0.1 - - [19/Aug/2014 15:23:41] "GET / HTTP/1.1" 404 - 127.0.0.1 - - [19/Aug/2014 15:23:42] "GET / HTTP/1.1" 404 - 

Any suggestions on what might be wrong?

Answer 1

You put your app.run() call too early :

 if __name__== '__main__': app.run() 

This is done before registering any of your routes. Move these two lines to the end of the file.

Next, your first line in show_entries() is incorrect:

 def show_entries(): db_get_db() 

There is no function db_get_db() ; it should be db = get_db() instead.

Answer 2

It also happened to me, following the Flask application setup here . The error disappeared after adding a slash at the end of the route.

 @app.route('/hello') def hello(): return 'Hello, World!' 

has been changed to

 @app.route('/hello/') def hello(): return 'Hello, World!' 

and the problem was resolved. Hope this helps anyone looking for such a problem.