Web development is an exciting, creative act; at its worst, it can be a repetitive, frustrating nuisance.
Django lets you focus on the fun stuff—the crux of your Web application— while easing the pain of
the repetitive bits. In doing so, it provides high-level abstractions of common Web development
patterns, shortcuts for frequent programming tasks, and clear conventions for how to solve
problems. At the same time, Django tries to stay out of your way, letting you work outside the scope
of the framework as needed. The goal of this book is to make you a Django expert. The focus is
twofold. First, we explain, in depth, what Django does and how to build Web applications with it.
Second, we discuss higher-level concepts where appropriate, answering the question “How can I
apply these tools effectively in my own projects?” By reading this book, you’ll learn the skills needed
to develop powerful Web sites quickly, with code that is clean and easy to maintain.
What Is a Web Framework?
Django is a prominent member of a new generation of Web frameworks. So, what exactly does that
term mean? To answer that question, let’s consider the design of a Web application written using
the Common Gateway Interface (CGI) standard, a popular way to write Web applications circa 1998.
In those days, when you wrote a CGI application, you did everything yourself—the equivalent of
baking a cake from scratch. For example, here’s a simple CGI script, written in Python, that displays
the ten most recently published books from a database:
#!/usr/bin/python
import MySQLdb
print "Content-Type: text/html"
print
print "<html><head><title>Books</title></head>"
print "<body>"
print "<h1>Books</h1>"
print "<ul>"
connection = MySQLdb.connect(user='me', passwd='letmein', db='my_db')
cursor = connection.cursor()
cursor.execute("SELECT name FROM books ORDER BY pub_date DESC LIMIT 10")
for row in cursor.fetchall():
print "<li>%s</li>" % row[0]
print "</ul>"
print "</body></html>"
connection.close()
This code is straightforward. First, it prints a “Content-Type” line, followed by a blank line, as
required by CGI. It prints some introductory HTML, connects to a database, and executes a query
that retrieves the latest ten books. Looping over those books, it generates an HTML unordered list.
Finally, it prints the closing HTML and closes the database connection. With a one-off dynamic page
