Errata

Introduction to Tornado

Errata for Introduction to Tornado

Submit your own errata for this product.

The errata list is a list of errors and their corrections that were found after the product was released.

The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.

Color Key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted by Date submitted
Printed Page 7
Example 1-2, lines 19,20

code snipset:

width = self.get_argument('width', 40)
self.write(textwrap.fill(text, width))

If there is no "width" argument in the POST request, then default value 40 will be used, and "get_argument" returns integer.
Variable "width" is INTEGER 40.
Example 1-2 works correctly.

If there is "width" argument in the POST request (let's say width=10),
then "get_argument" returns unicode string.
Variable "width" is now unicode string u'10'.
Example 1-2 now crashes in function textwrap.fill


In any case, thank you for the very interesting book.

Peter Leonov

 Anonymous  Apr 19, 2012 
PDF Page 17
code

This is not an errata, but a remainder for the reader using Tornado 2.2 on Python 3.2.2:
Don?t forget that in Python 3.2 the print method requires parenthesis surrounding the argument to be printed. The book?s code is written in Python 2.X series, so the reader must adjust the code lines involving the print statement.
For example, on page 17 we find the following statement:

print content.generate(header="Welcome!") # OK in Python 2.X series

So, if we?re working with Tornado 2.2 on Python 3.2.2, we must add surrounding parenthesis to avoid a mundane syntax error:

print( content.generate(header="Welcome!") ) # OK in Python 3.2 series

 ederandresan  Apr 10, 2012 
PDF Page 38
Example 3-1 code

On Ex 3-1, ui_modules needs to be a dictionary, so the line
> ui_modules={'Hello', HelloModule}
should be
> ui_modules={'Hello' : HelloModule}

 george  Mar 30, 2012 
38
middle of page, __main__

ui_modules={'Hello', HelloModule} should read:
ui_modules={'Hello': HelloModule}

(is a Python dictionary, needs a colon and not a comma as separator)

 Caleb Wright  Apr 03, 2012 
PDF Page 38
code

p038: Tornado 2.2 on Python 3.2.2. Missing import statement to execute the example app.

import tornado.web
import tornado.httpserver
import tornado.ioloop
import tornado.options
import os.path


It should be: ====>>>


import tornado.web
import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.locate
import os.path

 ederandresan  Apr 10, 2012 
PDF Page 38
code

Tornado 2.2 on Python 3.2.2. Dictionary syntax error.

app = tornado.web.Application(
handlers=[(r'/', HelloHandler)],
template_path=os.path.join(os.path.dirname(__file__), 'templates'),
ui_modules={'Hello', HelloModule}
)

===================================>>>

app = tornado.web.Application(
handlers=[(r'/', HelloHandler)],
template_path=os.path.join(os.path.dirname(__file__), 'templates'),
ui_modules={'Hello': HelloModule}

 ederandresan  Apr 10, 2012 
PDF Page 57
Example 4-3

Unused import statment:

import tornado.auth
import tornado.escape

 Matheus  Jul 29, 2012 
PDF Page 69
Example 5-1 , line 7 and line 20

In python3.2 change the values:
import urllib
urllib.urlencode({"q": query, "result_type": "recent", "rpp": 100}))

To:
import urllib.parse
urllib.parse.urlencode({"q": query, "result_type": "recent", "rpp": 100}))

 Matheus  Aug 02, 2012 
PDF Page 69
Example 5-3, line 21

In python3.2 json problem, need to decode it.
Change the values:

body = json.loads(response.body)

To:

body = json.loads(response.body.decode('utf-8'))

 Matheus  Aug 02, 2012 
69
code segment

The example uses twitter api v1 which is no longer supported, and as a result, you get an error 410

{"errors": [{"message": "The Twitter REST API v1 is no longer active. Please migrate to API v1.1. https://dev.twitter.com/docs/api/1.1/overview.", "code": 68}]}

 eran  Oct 10, 2013 
PDF Page 94
cookie_counter.py get method

The following part is syntactically incorrect.
self.write(
'<html><head><title>Cookie Counter</title></head>'
'<body><h1>You&rsquo;ve viewed this page %s times.</h1>' % countString
'</body></html>'
)


You need to join string literals with '+'

self.write(
'<html><head><title>Cookie Counter</title></head>' +
'<body><h1>You&rsquo;ve viewed this page %s times.</h1>' % countString +
'</body></html>'
)

 george  Apr 03, 2012 
PDF Page 99
Example 6-3. Login form: login.html

"xsrf_cookies" is set to true in the application, but xsrf_form_html declaration is missing from the login form.

 george  Apr 03, 2012 
PDF Page 100
code

Tornado 2.2 on Python 3.2.2. Missing RequestHandler.xsrf_form_html() method in the login.html file in order to Tornado process the post login request using the xsfr cookie protection:

Example 6-3. Login form: login.html

<html>
<head>
<title>Please Log In</title>
</head>
<body>
<form action="/login" method="post">
Username:<input type="text" name="username"/>
<input type="submit" value="Log In" />
</form>
</body>
</html>
===================================>>>
Example 6-3. Login form: login.html

<html>
<head>
<title>Please Log In</title>
</head>
<body>
<form action="/login" method="post">
{% raw xsrf_form_html() %}
Username:<input type="text" name="username"/>
<input type="submit" value="Log In" />
</form>
</body>
</html>

 ederandresan  Apr 10, 2012 
PDF Page 116-117
Source code

# Need to put upstream into http block:

worker_processes 2;

events
{
worker_connections 1024;
use epoll;
}

http
{
upstream tornadoes
{
server 127.0.0.1:8000;
server 127.0.0.1:8001;
}

server
{
listen 80;
server_name localhost;

location /reverse/
{
root /home/s/web/static;
if ($query_string)
{
expires max;
}
}

location /
{
proxy_pass_header Server;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_pass http://tornadoes;
}

proxy_next_upstream error;
}
}

 Anonymous  Jun 15, 2012