Pyton 实现SQLHelper

看了廖老师的教程实现了这个模块，按照自己的思路实现了一个，代码附下。

 

 

 

 

 

 

 

 

 

 

 

 

 

需要说名的几点：

1. dbcontext继承自threading.local，确保每个线程中都有独立的一个dbcontext对象，保证个用户数据独立。

2. connection对象是对dbcontext对象的一个封装，实现了getcursor方法，和关闭方法。

3. 现在的代码不够DRY，select方法和update方法调用了connection对象后都要手动关闭，可以实现一个装饰器，把要调用connection对象的代码块儿包裹起来，初始化和关闭connection对象的代码提取到装饰器中。下次补上。

代码附下：

 

  1 import MySQLdb,logging,threading,time,uuid

  2 logging.basicConfig(level=logging.INFO,format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s',datefmt='%a, %d %b %Y %H:%M:%S')

  3 

  4 def next_id(t=None):

  5     '''

  6     Return next id as 50-char string.

  7 

  8     Args:

  9         t: unix timestamp, default to None and using time.time().

 10     '''

 11     if t is None:

 12         t = time.time()

 13     return '%015d%s000' % (int(t * 1000), uuid.uuid4().hex)

 14 

 15 class Dict(dict):

 16     def __init__(self,names=(),values=(),**args):

 17         super(Dict,self).__init__(**args)

 18         for k,v in zip(names,values):

 19             self[k]=v

 20     def __getattr__(self, item):

 21         try:

 22             return self[item]

 23         except KeyError:

 24             raise AttributeError('it has no attribute named %s'%(str(item),))

 25     def __setattr__(self, key, value):

 26         self[key]=value

 27 

 28 class dbcontext(threading.local):

 29     def __init__(self):

 30         self.db= MySQLdb.connect(host="localhost",port=3306,passwd='toor',user='root',db='xdyweb')

 31     def getdb(self):

 32         return self.db

 33 

 34 class conntection(object):

 35     def __init__(self):

 36         self.dbctx=dbcontext()

 37         self.db=self.dbctx.getdb()

 38         self.cursor=self.db.cursor()

 39     def getcursor(self):

 40         return self.cursor

 41     def close(self):

 42         self.db.close()

 43         self.cursor=None

 44 def _select(sql,first,*args):

 45     conn=conntection()

 46     csr=conn.getcursor()

 47     sql=sql.replace('?','%s')

 48     values=csr.execute(sql,*args)

 49     try:

 50         if csr.description:

 51             names=[x[0] for x in csr.description]

 52         if first:

 53             values=csr.fetchone()

 54             if values is None:

 55                 return None

 56             return Dict(names,values)

 57         return  [Dict(names,x) for x in csr.fetchall()]

 58     finally:

 59         conn.close()

 60 

 61 def select(sql,first,*args):

 62     return _select(sql,first,*args)

 63 def select_one(sql,pk):

 64     return _select(sql,True,pk)

 65 

 66 def update(sql,*args):

 67     r'''

 68     Execute update SQL.

 69 

 70     >>> u1 = dict(id=1000, name='Michael', email='[email protected]', passwd='123456', last_modified=time.time())

 71     >>> insert('user', **u1)

 72     1

 73     >>> u2 = select_one('select * from user where id=?', 1000)

 74     >>> u2.email

 75     u'[email protected]'

 76     >>> u2.passwd

 77     u'123456'

 78     >>> update('update user set email=?, passwd=? where id=?', '[email protected]', '654321', 1000)

 79     1

 80     >>> u3 = select_one('select * from user where id=?', 1000)

 81     >>> u3.email

 82     u'[email protected]'

 83     >>> u3.passwd

 84     u'654321'

 85     >>> update('update user set passwd=? where id=?', '***', '123\' or id=\'456')

 86     0

 87     '''

 88     conn=conntection()

 89     csr=conn.getcursor()

 90     sql=sql.replace('?','%s')

 91 

 92     try:

 93         csr.execute(sql,args)

 94         return csr.rowcount

 95     finally:

 96         conn.close()

 97 def insert(table,**kw):

 98     '''

 99     Execute insert SQL.

100 

101     >>> u1 = dict(id=2000, name='Bob', email='[email protected]', passwd='bobobob', last_modified=time.time())

102     >>> insert('user', **u1)

103     1

104     >>> u2 = select_one('select * from user where id=?', 2000)

105     >>> u2.name

106     u'Bob'

107     >>> insert('user', **u2)

108     Traceback (most recent call last):

109       ...

110     IntegrityError: 1062 (23000): Duplicate entry '2000' for key 'PRIMARY'

111     '''

112     cols, args = zip(*kw.iteritems())

113     sql = 'insert into `%s` (%s) values (%s)' % (table, ','.join(['`%s`' % col for col in cols]), ','.join(['?' for i in range(len(cols))]))

114     logging.info(sql)

115     return update(sql,*args)

116 

117 def main():

118     # db=MySQLdb.connect(host="localhost",port=3306,passwd='toor',user='root',db='xdyweb')

119 

120     # conn=conntection()

121     # c=conn.getcursor()

122     # r=c.execute("select * from users where email=%s",('[email protected]',))

123     # logging.warning(r)

124 

125     # f=_select('select * from users where email =?',False,('[email protected]',))

126     # logging.info(f)

127     # pass

128 

129     u1 = dict(id=2000, name='Bob', email='[email protected]', passwd='bobobob', last_modified=time.time())

130     r=insert('user', **u1)

131     logging.info(r)

132 if __name__=="__main__":

133     main()

View Code