【python】TCP/IP编程

No1:

【TCP】

客户端

import socket

s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.connect(('www.sina.com.cn',80))
s.send(b'GET / HTTP/1.1\r\nHost: www.sina.com.cn\r\nConnection:close\r\n\r\n')

buffer=[]
while True:
    d=s.recv(1024)
    if d:
        buffer.append(d)
    else:
        break
data=b''.join(buffer)

s.close()

header,html = data.split(b'\r\n\r\n',1)
print(header.decode('utf-8'))
with open('sina.html','wb') as f:
    f.write(html)
    

运行结果得到一个sina.html文件，双击打开是新浪主页

服务端接受客户端

import socket,threading

s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.bind(('127.0.0.1',9999))
s.listen(5)
print('Waiting for connection...')

def tcplink(sock,addr):
    print('Accept new connection from %s:%s...' % addr)
    sock.send(b'Welcome!')
    while True:
        data = sock.recv(1024)
        time.sleep(1)
        if not data or data.decode('utf-8')=='exit':
            break
        sock.send(('Hello,%s' % data.decode('utf-8')).encode('utf-8'))
    sock.close()
    print('Connection from %s:%s closed.' % addr)

while True:
    sock,addr = s.accept()
    t=threading.Thread(target=tcplink,args=(sock,addr))
    t.start()

import socket

s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.connect(('127.0.0.1',9999))
print(s.recv(1024).decode('utf-8'))
for data in [b'Michael',b'Tracy',b'Sarah']:
    s.send(data)
    print(s.recv(1024).decode('utf-8'))
s.send(b'exit')
s.close()

No2：

【UDP】

服务端接受客户端

import socket

s=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
s.bind(('127.0.0.1',9999))

print('Bind UDP on 9999....')
while True:
    data,addr=s.recvfrom(1024)
    print('Received from %s:%s.' % addr)
    s.sendto(b'Hello,%s!' % data,addr)

import socket

s=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
for data in [b'Michael',b'Tracy',b'Sarah']:
    s.sendto(data,('127.0.0.1',9999))
    print(s.recv(1024).decode('utf-8'))
s.close()

运行结果

No3：

【SMTP发送邮件】

构造一个邮件对象就是一个Messag对象，如果构造一个MIMEText对象，就表示一个文本邮件对象，如果构造一个MIMEImage对象，就表示一个作为附件的图片，要把多个对象组合起来，就用MIMEMultipart对象，而MIMEBase可以表示任何对象。

from email import encoders
from email.header import Header
from email.mime.text import MIMEText
from email.utils import parseaddr,formataddr

import smtplib

def _format_addr(s):
    name,addr=parseaddr(s)
    return formataddr((Header(name,'utf-8').encode(),addr))

from_addr=input('From:')
password=input('Password:')
to_addr=input('To:')
smtp_server=input('SMTP server:')

msg=MIMEText('hello,send by Python...','plain','utf-8')
msg['From']=_format_addr('Python爱好者<%s>' % from_addr)
msg['To']=_format_addr('管理员<%s>' % to_addr)
msg['Subject']=Header('来自SMTP的问候。。。','utf-8').encode()

server=smtplib.SMTP(smtp_server,25)
server.set_debuglevel(1)
server.login(from_addr,password)
server.sendmail((from_addr,[to_addr],msg.as_string()))
server.quit()

发送附件

msg=MIMEMultipart()
msg['From']=_format_addr('Python爱好者<%s>'%from_addr)
msg['To']=_format_addr('管理员<%s>'%to_addr)
msg['Subject']=Header('来自SMTP的问候。。。','utf-8').encode()

msg.attach(MIMEText('send with file...','plain','utf-8'))

with open('/Users/michael/Download/test.png','rb') as f:
    mime=MIMEBase('image','png',filename='test.png')
    mime.add_header('Content-Disposition','attachment',filename='test.png')
    mime.add_header('Content-ID','<0>')
    mime.add_header('X-Attachment-Id','')
    mime.set_payload(f.read())
    encoders.encode_base64(mime)
    msg.attach(mime)

No4：

【Pop3接收邮件】

Python的poplib模块收取邮件分两步：第一步是用POP3协议把邮件获取到本地，第二步是用email模块把原始邮件解析为Message对象，然后，用适当的形式把邮件内容展示给用户即可。

先接收

import poplib

email=input('Email:')
password=input('Password:')
pop3_server=input('POP3 server:')

server=poplib.POP3(pop3_server)
server.set_debuglevel(1)
print(server.getwelcome().decode('utf-8'))

server.user(email)
server.pass_(password)

print('Message:%s. Size:%s' % server.stat())
resp,mails,octets=server.list()
print(mails)

index=len(mails)
resp,lines,octets=server.retr(index)

msg_content=b'\r\n'.join(lines).decode('utf-8')
msg=Parser().parsestr(msg_content)

server.quit()

再解析

from email.parser import Parser
from email.header import decode_header
from email.utils import parseaddr

import poplib

msg=Parser().parsestr(msg_content)

def print_info(msg,indent=0):
    if indent==0:
        for header in ['From','To','Subject']:
            value=msg.get(header,'')
            if value:
                if header == 'Subject':
                    value = decode_str(value)
                else:
                    hdr,addr=parseaddr(value)
                    name=decode_str(hdr)
                    value=u'%s<%s>' % (name,addr)
            print('%s%s: %s' % ('  ' * indent,header,value))
    if(msg,is_multipart()):
        parts=msg.get_payload()
        for n,part in enumerate(parts):
            print('%spart %s' % ('  ' * indent,n))
            print('%s------------------' % ('   ' * indent))
            print_info(part,indent+1)
    else:
        content_type=msg.get_content_type()
        if content_type=='text/plan' or content_type=='text/html':
            content=msg.get_payload(decode=True)
            charset=guess_charset(msg)
            if charset:
                content=content.decode(charset)
            print('%sText: %s' % ('   ' * indent,content + '...'))
        else:
            print('%sAttachment: %s' % ('  ' * indent,content_type))

def decode_str(s):
    value,charset = decode_header(s)[0]
    if charset:
        value = value.decode(charset)
    return value

def guess_charset(msg):
    charset=msg.get_charset()
    if charset is None:
        content_type=msg.get('Content-Type','').lower()
        pos=content_type.find('charset=')
        if pos >= 0:
            charset=content_type[pos + 8].strip()
    return charset