python项目练习七：自定义公告板

the5fire

发布于 2019-02-28 15:43:18

4960

发布于 2019-02-28 15:43:18

这依然是一个cgi的项目，有了前面的一个项目作为基础，这个里面没有什么难点。不过，和书上不同的是，我这里使用的数据库是mysql，所以有兴趣的童鞋，可以参考一下。

首先建立一张mysql的数据表：

CREATE TABLE messages(
    id INT NOT NULL AUTO_INCREMENT,
    subject VARCHAR(100) NOT NULL,
    reply_to INT,
    text MEDIUMTEXT NOT NULL,
    PRIMARY KEY(id)
)

然后你要确定你的系统中已经安装了连接mysql的python模块，怎么确定呢。命令行下，进入python，然后输入import MySQLdb,注意大小写，如果没有报错，说明安装了，如果报错，从网上找python连mysql的方法，很多。

准备就绪，开始分析整个程序吧。

一个很简单的电子公告版，主要功能有，展示所有公告，查看单个公告，编辑公告，保存公告。所以根据功能建立四个文件：main.py,view.py,edit.py,save.py，每个文件，负责一个模块。

下面就上代码吧，太简单了。 main.py:

.. code:: python

#!/usr/bin/python

print 'Content-type:text/html\n'
print 
#import cgitb:cgitb.enable()

import MySQLdb

conn = MySQLdb.connect(db='usernet',host='127.0.0.1',user='root',passwd='root')

curs = conn.cursor()

print '''
<html>
  <head>
    <title>The UserNet</title>
  </head>
  <body>
    <h1>The UserNet</h1>
'''

sql = 'SELECT * FROM message'
curs.execute(sql)

rows = curs.fetchall()
toplevel = []
children = {}

for row in rows:
        parent_id = row[3]
        if parent_id is None:
                toplevel.append(row)
        else:
                children.setdefault(parent_id,[]).append(row)

        def format(row):
                print '<p><a href="view.cgi?id=%i">%s<a>' % (row[0],row[1])
                try:
                        kids = children[row[0]]
                except KeyError:
                        pass
                else:
                        print '<blockquote>'
                        for kid in kids:
                                format(kid)

                        print '</blockquote>'

        print '<p>'

        for row in toplevel:
                format(row)

print '''
</p>
<hr/>
<p><a href="edit.cgi">Post Message</a></p>
</body>
</html>
'''

view.py

.. code:: python

#!/usr/bin/python

print 'Content-type:text/html\n'

import cgitb;cgitb.enable()

import MySQLdb

conn = MySQLdb.connect(db='usernet',host='127.0.0.1',user='root',passwd='root')
curs = conn.cursor()

import cgi, sys
form = cgi.FieldStorage()
id = form.getvalue('id')

print '''
<html>
  <head>
    <title>View Message</title>
  </head>
  <body>
    <h1>View Message</h1>
    '''

try: id = int(id)
except:
        print 'Invalid message ID'
        sys.exit()

curs.execute('SELECT * FROM message WHERE id = %i' % id)
rows = curs.fetchall()

if not rows:
        print 'Unknown message ID'
        sys.exit()

row = rows[0]

print '''
<p><b>Subject:</b> %s<br/>
<b>Sender:</b>%s<br/>
<pre>%s</pre>
</p>
<hr/>
<a href='main.cgi'>Back to the main page</a>
|<a href="edit.cgi?reply_to=%s">Reply</a>
</body>
</html>
''' % (row[1],row[2],row[4],row[0])

edit.py

.. code:: python

#!/usr/bin/python

print 'Content-type:text/html\n'

import cgitb;cgitb.enable()

import MySQLdb
conn = MySQLdb.connect(db='usernet',host='127.0.0.1',user='root',passwd='root')
curs = conn.cursor()

import cgi,sys
form = cgi.FieldStorage()
reply_to = form.getvalue('reply_to')

print '''
<html>
  <head>
    <title>Compose Message</title>
  </head>
  <body>
    <h1>Compose Message</h1>

    <form action='save.cgi' method='POST'>
    '''

subject = ''
if reply_to is not None:
        print '<input type="hidden" name="reply_to" value="%s"/>' % reply_to
        curs.execute('SELECT subject FROM message WHERE id = %s' % reply_to)
        subject = curs.fetchone()[0]
        if not subject.startswith('Re: '):
                subject = 'Re:  ' + subject
print '''
    <b>Subject:</b><br/>
    <input type='text' size='40' name='subject' value='%s' /><br/>
    <b>Sender:</b><br/>
    <input type='text' size='40' name='sender' /><br/>
    <b>Message:</b><br/>
    <textarea name='text' cols='40' rows='20'></textarea><br/>
    <input type='submit' value='Save'/>
    </form>
    <hr/>
    <a href='main.cgi'>back to the main page</a>
    </body>
    </html>
    ''' % subject

save.py

.. code:: python

#!/usr/bin/python

print 'Content-type:text/html\n'

import cgitb;cgitb.enable()

def quote(string):
        if string:
                return string.replace("'","\\'")
        else:
                return string

import MySQLdb
conn = MySQLdb.connect(db='usernet',host='127.0.0.1',user='root',passwd='root')
curs = conn.cursor()

import cgi, sys
form = cgi.FieldStorage()

sender = quote(form.getvalue('sender'))
subject = quote(form.getvalue('subject'))
text = quote(form.getvalue('text'))
reply_to = form.getvalue('reply_to')

if not (sender and subject and text):
        print 'Please supply sender,subject,text'
        sys.exit()

if reply_to is not None:
        query = """
        INSERT INTO message(reply_to,sender,subject,text)
        VALUES(%d,'%s','%s','%s')""" % (int(reply_to),sender,subject,text)
else:
        query = """
        INSERT INTO message(sender,subject,text) 
        VALUES('%s','%s','%s')""" % (sender,subject,text)

curs.execute(query)
conn.commit()

print '''
<html>
  <head>
    <title>Message Save</title>
  </head>
  <body>
    <h1>Message Saved</h1>
    <hr/>
    <a href='main.cgi'>Back to the main page</a>
  </body>
</html>s
'''

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原始发表：2012-01-04 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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