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python练习六—简单的论坛

2018-02-28 09:04 399 查看
进行简单的web应用之后，接下来就应该学习python连接数据库，这个练习就是在上个练习的基础上将信息保存到数据库，这个联系也没有什么特别的，有之前java web的经验的话，很好理解，主要还是一个MySQLdb的学习。代码如下（创建数据库就忽略了吧）：

从数据库查询message以列表的形式显示main.py

#! /usr/bin/env python
# -*- coding=utf-8 -*-

import cgitb
import MySQLdb

# 声明文本格式
print 'Content-type:text/html\n'

cgitb.enable()

# 连接数据库
conn = MySQLdb.connect(user='root', db='test')
curs = conn.cursor()

print """
<html>
<head>
<title>主页</title>
</head>
<body>
<h1>论坛帖子列表</h1>
"""

# 将数据库中记录读取到dic
curs.execute('select * from messages')
# mysql没有这样的方法
# rows = curs.dictfetchall()
# 获取表的列的名称
names = [d[0] for d in curs.description]
print names
rows = [dict(zip(names, row)) for row in curs.fetchall()]
print rows

# 主贴
toplevel = []
# 回复帖
children = {}

# 区分出主贴和回复帖
for row in rows:
parent_id = row['reply_to']
if parent_id is None:
toplevel.append(row)
else:
children.setdefault(parent_id, []).append(row)

# 格式化帖子列表
def format(row):
print '<p><a href="view.py?id=%(id)s">%(subject)s </a></p>'% row
try:
kids = children[row['id']]
except KeyError:
pass
else:
# 递归格式化帖子的子贴（回复）
print '<blockquote>'
for kid in kids:
format(kid)
print '</blockquote>'
print '<p>'

# 调用format格式化帖子
for row in toplevel:
format(row)

print """
</p>
<hr />
<p><a href="edit.py">发帖</a></p>
</bofy>
</html>
"""


查看一个具体帖子的详细内容view.py

#! /usr/bin/env python
# -*- coding=utf-8 -*-

import cgitb
import sys
import cgi
import MySQLdb

# 声明文本格式
print 'Content-type:text/html\n'

cgitb.enable()

# 接受参数
form = cgi.FieldStorage()
id = form.getvalue('id')

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

# 连接数据库
conn = MySQLdb.connect(user='root', db='test')
curs = conn.cursor()

print """
<html>
<head>
<title>View message</title>
</head>
<body>
<h1>View Message</h1>
"""

# 将数据库中记录读取到dic
curs.execute('select * from messages where id = %i' % id)
# mysql没有这样的方法
# rows = curs.dictfetchall()
# 获取表的列的名称
names = [d[0] for d in curs.description]
#print names
rows = [dict(zip(names, row)) for row in curs.fetchall()]
#print rows

# 如果该id查询不到数据，说明不存在该id
if not rows:
print 'Unknow message id'
sys.exit()

# 获取返回的第一条数据
row = rows[0]

print """
<p>
<b> Subject: </b>%(subject)s <br />
<b> sender: </b>%(sender)s <br />
<pre>%(text)s</pre>
</p>
<hr />
<a href="main.py">back to main page</a>>
|
<a href="edit.py?reply_to=%(id)s"> reply</a>
</bofy>
</html>
""" % row


查看完帖子之后回帖，edit.py

#! /usr/bin/env python
# -*- coding=utf-8 -*-

import cgitb
import sys
import cgi
import MySQLdb

# 声明文本格式
print 'Content-type:text/html\n'

cgitb.enable()

# 接受参数
form = cgi.FieldStorage()
reply_to = form.getvalue('reply_to')

# 连接数据库
conn = MySQLdb.connect(user='root', db='test')
curs = conn.cursor()

print """
<html>
<head>
<title>View message</title>
</head>
<body>
<h1>View Message</h1>
<form action="save.py" method="POST">
"""

subject = ''
if reply_to is not None:
print "<input type='hidden' name='reply_to' value='%s' />" % reply_to
curs.execute('select * from messages where id=%s' % reply_to)
subject = curs.fetchone()[1]
print subject
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.py'>Back to the main page</a>'
</body>
</html>
""" % subject


编辑完帖子的时候，提交save.py

#!/usr/bin/python
# -*- coding=utf-8 -*-

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

import cgitb; cgitb.enable()

# 将单引号转义，在使用insert语句的时候字符串就不需要添加引号
def quote(string):
if string:
return string.replace("'", "\\'")
else:
return string

import MySQLdb
conn = MySQLdb.connect(db='test', user='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, and text'
sys.exit()

if reply_to is not None:
query = """
insert into messages(reply_to, sender, subject, text)
values(%i, '%s', '%s', '%s')""" % (int(reply_to), sender, subject, text)
else:
query = """
insert into messages(sender, subject, text)
values('%s', '%s', '%s')""" % (sender, subject, text)

curs.execute(query)
conn.commit()

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


 

 

 

完整代码

http://pan.baidu.com/s/1gfbLDtx
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