1用MySQLdb模块操作MySQL数据库非常方便。示例代码如下:
import os, sys
import MySQLdb
try:
conn MySQLdb.connect(host=’localhost’,user=’root’,passwd=’’,db=’address’
except Exception,e:
print e
sys.exit()
cursor=conn.cursor()
sql=’insert into address(name, address) values(%s, %s)’
value=((“zhangsan”,”haidian”),(“lisi”,”haidian”))
try
cursor.executemany(sql,values)
except Exception, e:
print e
sql=”select * from address”
cursor.execute(sql)
data=cursor.fetchall()
if data
for x in data:
print x[0],x[1]
cursor.close()
conn.close()
2、网络基础
1)利用Socket建立网络连接的步骤:
建立Socket连接至少需要一对套接字,其中一个运行于客户端,称为ClientSocket ,另一个运行于服务器端,称为ServerSocket 。
套接字之间的连接过程分为三个步骤:服务器监听,客户端请求,连接确认。
1。服务器监听:服务器端套接字并不定位具体的客户端套接字,而是处于等待连接的状态,实时监控网络状态,等待客户端的连接请求。
2。客户端请求:指客户端的套接字提出连接请求,要连接的目标是服务器端的套接字。为此,客户端的套接字必须首先描述它要连接的服务器的套接字,指出服务器端套接字的地址和端口号,然后就向服务器端套接字提出连接请求。
3。连接确认:当服务器端套接字监听到或者说接收到客户端套接字的连接请求时,就响应客户端套接字的请求,建立一个新的线程,把服务器端套接字的描述发给客户端,一旦客户端确认了此描述,双方就正式建立连接。而服务器端套接字继续处于监听状态,继续接收其他客户端套接字的连接请求。
2)HTTP链接的特点
HTTP协议即超文本传送协议(Hypertext Transfer Protocol ),是Web联网的基础,也是手机联网常用的协议之一,HTTP协议是建立在TCP协议之上的一种应用。
HTTP连接最显著的特点是客户端发送的每次请求都需要服务器回送响应,在请求结束后,会主动释放连接。从建立连接到关闭连接的过程称为“一次连接”。
3)Python网络编程
3.1)Python提供了访问底层操作系统Socket接口的全部方法,还提供了一组加密和认证通信的服务,SSL/TLS。
Sockets其实是一个文件描述符,不同于不同于本地文件,它连接了网络上的一个文件。
a)、创建一个UDP 本地连接:
#!/usr/bin/env python
import socket, sys
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
MAX = 65535
PORT = 1060
if sys.argv[1:] == ['server']:
s.bind(('127.0.0.1', PORT))
print 'Listening at', s.getsockname()
while True:
data, address = s.recvfrom(MAX)
print 'The client at', address, 'says', repr(data)
s.sendto('Your data was %d bytes' % len(data), address)
elif sys.argv[1:] == ['client']:
print 'Address before sending:', s.getsockname()
s.sendto('This is my message', ('127.0.0.1', PORT))
print 'Address after sending', s.getsockname()
data, address = s.recvfrom(MAX) # overly promiscuous - see text!
print 'The server', address, 'says', repr(data)
else:
print >>sys.stderr, 'usage: udp_local.py server|client'
b)运行这段代码:
python filename.py server
#Listening at ('127.0.0.1', 1060)
#Address before sending: ('0.0.0.0', 0)
#Address after sending ('0.0.0.0', 62892)
#The server ('127.0.0.1', 1060) says 'Your data was 18 bytes'
python filename.py client
#The client at ('127.0.0.1', 62892) says 'This is my message'
3.2)、创建远程连接并验证收到的信息:
import random, socket, sys
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
MAX = 65535
PORT = 1060
if 2 <= len(sys.argv) <= 3 and sys.argv[1] == 'server':
interface = sys.argv[2] if len(sys.argv) > 2 else ''
s.bind((interface, PORT))
print 'Listening at', s.getsockname()
while True:
data, address = s.recvfrom(MAX)
if random.randint(0, 1):
print 'The client at', address, 'says:', repr(data)
s.sendto('Your data was %d bytes' % len(data), address)
else:
print 'Pretending to drop packet from', address
elif len(sys.argv) == 3 and sys.argv[1] == 'client':
hostname = sys.argv[2]
s.connect((hostname, PORT))
print 'Client socket name is', s.getsockname()
delay = 0.1
while True:
s.send('This is another message')
print 'Waiting up to', delay, 'seconds for a reply'
s.settimeout(delay)
try:
data = s.recv(MAX)
except socket.timeout:
delay *= 2 # wait even longer for the next request
if delay > 2.0:
raise RuntimeError('I think the server is down')
else:
break # we are done, and can stop looping
print 'The server says', repr(data)
else:
print >>sys.stderr, 'usage: udp_remote.py server [ <interface> ]'
print >>sys.stderr, ' or: udp_remote.py client <host>'
sys.exit(2)
这里的s.connect((hostname, PORT))方法,可以让我们不用每次都调用s.sendto('This is my message', ('127.0.0.1', PORT))。直接调用
s.send('This is another message')。
3.3)SOCKET
socket是操作系统中I/O的延续,它可以使进程和机器之间的通信成为可能。socket可以看成一个标准的文件描述符。不同的是文件需要用open()函数打开,而socket用socket()
函数建立.recv()、send()函数和read()、write()函数极为相似。
TCP一般通过accept()来为每个连接的客户端建立一个新的scoket。UDP一般只是使用一个单一的socket,完全依靠recvfrom()返回的值来判断该往哪里发送响应。
客户端:
1、建立一个socket:
//SOCK_STREAM表示TCP,SOCK_DGRAM表示UDP,AF_INET表示IPv4
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
2、连接socket
连接socket需要一个tuple参数,来提供IP和端口号:
s.connect((“www.example.com”, 80))
3、
#!/usr/bin/env python
import socket
print "Creating socket...",
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print "done."
print "Looking up port number...",
port = socket.getservbyname('http', 'tcp')
print "done."
print "Connecting to remote host on port %d..." % port,
s.connect(("www.google.com", port))
print "done."
#获取本身的IP和端口号
print "Connected from", s.getsockname()
#获取远程的IP和端口号
print "Connected to", s.getpeername()
文件类对象:
import socket, sys
port = 70
host = sys.argv[1]
filename = sys.argv[2]
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
fd = s.makefile('rw', 0)
fd.write(filename + "\r\n")
for line in fd.readlines():
sys.stdout.write(line)
高级接口:
import urllib, sys
f = urllib.urlopen(sys.argv[1])
while 1:
buf = f.read(2048)
if not len(buf):
break
sys.stdout.write(buf)
服务器端:
1、建立一个连接:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
2、设置socket选项:
//socket 端口可立即复用
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
3、绑定socket:
s.bind((host, port))
4、监听:
s.listen(1)
5、接受连接:
while 1:
clientsock, clientaddr = s.accept()
print "Got connection from", clientsock.getpeername()
clientsock.close()
6、
#!/usr/bin/env python
import socket, traceback
host = '' # Bind to all interfaces
port = 51423
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
#这里设定每次最多只有一个等候处理的请求,真正的服务器会设置一个很高的数字。
s.listen(1)
while 1:
try:
clientsock, clientaddr = s.accept()
except KeyboardInterrupt:
raise
except:
traceback.print_exc()
continue
# Process the connection
try:
print "Got connection from", clientsock.getpeername()
# Process the request here
except (KeyboardInterrupt, SystemExit):
raise
except:
traceback.print_exc()
# Close the connection
try:
clientsock.close()
except KeyboardInterrupt:
raise
except:
traceback.print_exc()
使用UDP:
#!/usr/bin/env python
import socket, traceback
host = '' # Bind to all interfaces
port = 51423
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
while 1:
try:
message, address = s.recvfrom(8192)
print "Got data from", address
# Echo it back
s.sendto(message, address)
except (KeyboardInterrupt, SystemExit):
raise
except:
traceback.print_exc()