I am new to tornado and web service development, and currently implementing a tiny web for practising tornado module.
This is the python code I used for my server
import bcrypt
import concurrent.futures
#import MySQLdb
#import markdown
import os.path
import re
import subprocess
#import torndb
import tornado.escape
from tornado import gen
import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import unicodedata
from tornado.options import define, options
define("port",default=8889,help='run on the given port',type=int)
class HomeHandler(tornado.web.RequestHandler):
def get(self):
#login here
self.render('index.html')
def post(self):
def readcodebook(codebook):
with open(codebook,'r+') as f:
CodeLines=f.read().split('\n')
combinations={}
for c in CodeLines:
if len(c)>0:
combinations[c.split('\t')[0]]=c.split('\t')[1]
return combinations
UserFile='/home/john/PyServer/Users/codebook.txt'
CodeBook=readcodebook(UserFile)
if self.get_argument("login") in CodeBook.keys():
if CodeBook[self.get_argument("login")]==self.get_argument("password"):
#correct pwd
self.redirect(self.get_argument("next","/display/"))
else:
#incorrect pwd
self.render("index.html", error='incorrect password!')
return
else:
#user not found
self.render("index.html", error="account not found!")
return
class DisplayHandler(tornado.web.RedirectHandler):
def get(self):
self.render("displaycontent.html")
pass
class Application(tornado.web.Application):
def __init__(self):
handlers = [
(r"/", HomeHandler),
(r"/display/", DisplayHandler),
]
settings = dict(
#blog_title=u"Tornado Blog",
template_path=os.path.join(os.path.dirname(__file__), "templates"),
static_path=os.path.join(os.path.dirname(__file__), "static"),
#ui_modules={"Entry": EntryModule},
#xsrf_cookies=True,
#cookie_secret="__TODO:_GENERATE_YOUR_OWN_RANDOM_VALUE_HERE__",
#login_url="/auth/login",
debug=True,
)
tornado.web.Application.__init__(self,handlers,**settings)
if __name__=="__main__":
tornado.options.parse_command_line()
http_server=tornado.httpserver.HTTPServer(Application())
http_server.listen(options.port)
tornado.ioloop.IOLoop.instance().start()
and this is the index.html for user logon:
CSSFlow
Login Form
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<!DOCTYPE html>
<!--[if lt IE 7]> <html class="lt-ie9 lt-ie8 lt-ie7" lang="en"> <![endif]-->
<!--[if IE 7]> <html class="lt-ie9 lt-ie8" lang="en"> <![endif]-->
<!--[if IE 8]> <html class="lt-ie9" lang="en"> <![endif]-->
<!--[if gt IE 8]><!--> <html lang="en"> <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Login Form</title>
<link rel="stylesheet" href="css/style.css">
<!--[if lt IE 9]><script src="//html5shim.googlecode.com/svn/trunk/html5.js"></script><![endif]-->
</head>
<body>
<section class="container">
<div class="login">
<h1>Login to Web App</h1>
<form method="post" action="/">
<p><input type="text" name="login" value="" placeholder="Username or Email"></p>
<p><input type="password" name="password" value="" placeholder="Password"></p>
<p class="remember_me">
<label>
<input type="checkbox" name="remember_me" id="remember_me">
Remember me on this computer
</label>
</p>
<p class="submit"><input type="submit" name="commit" value="Login"></p>
</form>
</div>
<div class="login-help">
<p>Forgot your password? <a href="index.html">Click here to reset it</a>.</p>
</div>
</section>
<section class="about">
<p class="about-links">
<a href="http://www.cssflow.com/snippets/login-form" target="_parent">View Article</a>
<a href="http://www.cssflow.com/snippets/login-form.zip" target="_parent">Download</a>
</p>
<p class="about-author">
© 2012–2013 <a href="http://thibaut.me" target="_blank">Thibaut Courouble</a> -
<a href="http://www.cssflow.com/mit-license" target="_blank">MIT License</a><br>
Original PSD by <a href="http://www.premiumpixels.com/freebies/clean-simple-login-form-psd/" target="_blank">Orman Clark</a>
</section>
</body>
</html>
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The problem now is that tornado will throw an uncaught exception with description below and shows Error 404 not found in web browser, when I click submit button in index.html with correct username and password:
[E 170108 11:21:55 http1connection:54] Uncaught exception
Traceback (most recent call last):
File "/home/gaobo/anaconda3/lib/python3.5/site-packages/tornado/http1connection.py", line 238, in _read_message
delegate.finish()
File "/home/gaobo/anaconda3/lib/python3.5/site-packages/tornado/httpserver.py", line 289, in finish
self.delegate.finish()
File "/home/gaobo/anaconda3/lib/python3.5/site-packages/tornado/web.py", line 2022, in finish
self.execute()
File "/home/gaobo/anaconda3/lib/python3.5/site-packages/tornado/web.py", line 2042, in execute
**self.handler_kwargs)
File "/home/gaobo/anaconda3/lib/python3.5/site-packages/tornado/web.py", line 183, in __init__
self.initialize(**kwargs)
TypeError: initialize() missing 1 required positional argument: 'url'
Could anybody here point out a way to fix this problem? Thanks a lot!
Tornado offers you two ways to accomplish a redirection. One using the RedirectHandler and the other way using the redirect method of the RequestHandler.
On your example above you mixed these two ways causing the error you get.
On your example, since you use the second way (RequestHandler.redirect), to accomplish a redirection to the displaycontent.html on a successful login, you need to replace the parent class of the DisplayHandler to be the
RequestHandler innstead of the RedirectHandler.
eg.
class DisplayHandler(tornado.web.RequestHandler):
def get(self):
self.render("displaycontent.html")
Also the parameters of the redirect method should only be the url(or alias) you want to redirect to.
eg.
#correct pwd
self.redirect("/display/")
If you are interested in some more reading for the redirection follow this link.