《使用python进行unix和linux管理》§5 网络 §5.1 网络客户端

oychw

               
       
       
       
       
       
       
       
       
       
       
       
       
§5        网络
2009-9-13
磁针石：xurongzhong#gmail.com
博客：
oychw.cublog.cn
§5.1 网络客户端
§5.1.1 socket
#
python
Python
2.6.2 (r262:71600, Apr 29 2009, 14:54:06)
[GCC
3.4.6 20060404 (Red Hat 3.4.6-9)] on linux2
Type
"help", "copyright", "credits" or
"license" for more information.
>>>
import socket
>>>
s = socket.socket()
>>>
s.connect(('10.50.20.100', 80))           
>>>
s.send("GET / HTTP/1.0\n\n")
16
>>>
s.recv(200)
'HTTP/1.1
200 OK\r\nDate: Tue, 26 May 2009 07:49:43 GMT\r\nServer:
Apache/2.0.52 (Red Hat)\r\nX-Powered-By: PHP/4.3.9\r\nContent-Length:
7789\r\nConnection: close\r\nContent-Type: text/html;
charset=UTF-8\r\n\r\n
>>>
s.close()
以下程序检查指定的机器的制定端口是否打开，即TCP端口检测：
#
cat port_checker_tcp.py
#!/usr/bin/env
python
import
socket
import
re
import
sys
def
check_server(address, port):
    #create
a TCP socket
    s
= socket.socket()
    print
"Attempting to connect to %s on port %s" % (address, port)
    try:
        s.connect((address,
port))
        print
"Connected to %s on port %s" % (address, port)
        return
True
    except
socket.error, e:
        print
"Connection to %s on port %s failed: %s" % (address, port,
e)
        return
False
if
__name__ == '__main__':
    from
optparse import OptionParser
    parser
= OptionParser()
    parser.add_option("-a",
"--address", dest="address", default='localhost',
                      help="ADDRESS
for server", metavar="ADDRESS")
    parser.add_option("-p",
"--port", dest="port", type="int",
default=80,
                      help="PORT
for server", metavar="PORT")
    (options,
args) = parser.parse_args()
    print
'options: %s, args: %s' % (options, args)
    check
= check_server(options.address, options.port)
    print
'check_server returned %s' % check
    sys.exit(not
check)
#
./port_checker_tcp.py -a 10.50.20.100 -p 80
options:
{'port': 80, 'address': '10.50.20.100'}, args: []
Attempting
to connect to 10.50.20.100 on port 80
Connected
to 10.50.20.100 on port 80
check_server
returned True
#
./port_checker_tcp.py -a 10.56.3.110 -p 3302         
options:
{'port': 3302, 'address': '10.56.3.110'}, args: []
Attempting
to connect to 10.56.3.110 on port 3302
Connected
to 10.56.3.110 on port 3302
check_server
returned True
sys.exit(not
check)的实质是把返回值取反，以适合shell的调用。
以下程序检测socket检测web服务，检查指定网站的指定网页是否存在。
#
cat web_server_checker_tcp.py   
#!/usr/bin/env
python
import
socket
import
re
import
sys
def
check_webserver(address, port, resource):
    #build
up HTTP request string
    if
not resource.startswith('/'):
        resource
= '/' + resource
    request_string
= "GET %s HTTP/1.1\r\nHost: %s\r\n\r\n" % (resource,
address)
    print
'HTTP request:'
    print
'|||%s|||' % request_string
    #create
a TCP socket
    s
= socket.socket()
    print
"Attempting to connect to %s on port %s" % (address, port)
    try:
      
s.connect((address, port))
        print
"Connected to %s on port %s" % (address, port)
      
s.send(request_string)
        #we
should only need the first 100 bytes or so
        rsp
= s.recv(100)
        print
'Received 100 bytes of HTTP response'
        print
'|||%s|||' % rsp
    except
socket.error, e:
        print
"Connection to %s on port %s failed: %s" % (address, port,
e)
        return
False
    finally:
        #be
a good citizen and close your connection
        print
"Closing the connection"
        s.close()
    lines
= rsp.splitlines()
    print
'First line of HTTP response: %s' % lines[0]
    try:
        version,
status, message = re.split(r'\s+', lines[0], 2)
        print
'Version: %s, Status: %s, Message: %s' % (version, status, message)
    except
ValueError:
        print
'Failed to split status line'
        return
False
    if
status in ['200', '301']:
        print
'Success - status was %s' % status
        return
True
    else:
        print
'Status was %s' % status
        return
False
if
__name__ == '__main__':
    from
optparse import OptionParser
    parser
= OptionParser()
   
parser.add_option("-a",
"--address", dest="address", default='localhost',
                  
   help="ADDRESS for
webserver", metavar="ADDRESS")
   
parser.add_option("-p",
"--port", dest="port", type="int",
default=80,
                  
   help="PORT for webserver",
metavar="PORT")
   
parser.add_option("-r",
"--resource", dest="resource",
default='index.html',
                  
   help="RESOURCE to check",
metavar="RESOURCE")
    (options,
args) = parser.parse_args()
    print
'options: %s, args: %s' % (options, args)
    check
= check_webserver(options.address, options.port, options.resource)
    print
'check_webserver returned %s' % check
    sys.exit(not
check)
如果有高层次的库，建议不要直接调用socket，这样耗时耗力。
§5.1.2 httplib
这里是把上边的例子用httplib实现。
#
cat web_server_checker_httplib.py   
#!/usr/bin/env
python
import
httplib
import
sys
def
check_webserver(address, port, resource):
    #create
connection
    if
not resource.startswith('/'):
        resource
= '/' + resource
    try:
        conn
= httplib.HTTPConnection(address, port)
        print
'HTTP connection created successfully'
        #make
request
        req
= conn.request('GET', resource)
        print
'request for %s successful' % resource
        #get
response
        response
= conn.getresponse()
        print
'response status: %s' % response.status
    except
sock.error, e:
        print
'HTTP connection failed: %s' % e
        return
False
    finally:
        conn.close()
        print
'HTTP connection closed successfully'
    if
response.status in [200, 301]:
        return
True
    else:
        return
False
if
__name__ == '__main__':
    from
optparse import OptionParser
    parser
= OptionParser()
    parser.add_option("-a",
"--address", dest="address", default='localhost',
                      help="ADDRESS
for webserver", metavar="ADDRESS")
    parser.add_option("-p",
"--port", dest="port", type="int",
default=80,
                      help="PORT
for webserver", metavar="PORT")
    parser.add_option("-r",
"--resource", dest="resource",
default='index.html',
                      help="RESOURCE
to check", metavar="RESOURCE")
    (options,
args) = parser.parse_args()
    print
'options: %s, args: %s' % (options, args)
    check
= check_webserver(options.address, options.port, options.resource)
    print
'check_webserver returned %s' % check
    sys.exit(not
check)
§5.1.3 ftplib
从ftp服务器获取一个文件：
#
cat url_retrieve_ftp_ftplib.py
#!/usr/bin/env
python
from
ftplib import FTP
import
ftplib
import
sys
from
optparse import OptionParser
parser
= OptionParser()
parser.add_option("-a",
"--remote_host_address", dest="remote_host_address",
    help="REMOTE
FTP HOST.",
   
metavar="REMOTE FTP HOST")
parser.add_option("-r",
"--remote_file", dest="remote_file",
    help="REMOTE
FILE NAME to download.",
   
metavar="REMOTE FILE NAME")
parser.add_option("-l",
"--local_file", dest="local_file",
    help="LOCAL
FILE NAME to save remote file to", metavar="LOCAL FILE
NAME")
parser.add_option("-u",
"--username", dest="username",default="Anonymous",
    help="USERNAME
for ftp server", metavar="USERNAME")
parser.add_option("-p",
"--password", dest="password",default="Anonymous",
    help="PASSWORD
for ftp server", metavar="PASSWORD")
(options,
args) = parser.parse_args()
if
not (options.remote_file and
      
options.local_file and
      
options.remote_host_address):
   
parser.error('REMOTE HOST, LOCAL
FILE NAME, ' \
            'and
REMOTE FILE NAME are mandatory')
if
options.username and not options.password:
   
parser.error('PASSWORD is
mandatory if USERNAME is present')
ftp
= FTP(options.remote_host_address)
if
options.username:
    try:
      
ftp.login(options.username,
options.password)
    except
ftplib.error_perm, e:
        print
"Login failed: %s" % e
      
sys.exit(1)
else:
    try:
      
ftp.login()
    except
ftplib.error_perm, e:
        print
"Anonymous login failed: %s" % e
      
sys.exit(1)
try:
    local_file
= open(options.local_file, 'wb')
   
ftp.retrbinary('RETR %s' %
options.remote_file, local_file.write)
finally:
   
local_file.close()
    ftp.close()
运行示例：
#
./url_retrieve_ftp_ftplib.py -a ftp.pku.edu.cn -r welcome.msg -l
/root/welcome.msg
§5.1.3
urllib
本例子把上述例子用更高级别的urllib实现。
#
cat  url_retrieve_urllib.py
#!/usr/bin/env
python
"""
url
retriever
Usage:
   
url_retrieve_urllib.py
URL FILENAME
URL:
If
the URL is an FTP URL the format should be:
ftp://[username[:password]@]hostname/filename
If
you want to use absolute paths to the file to download,
you
should make the URL look something like this:
ftp://user:password@host/%2Fpath/to/myfile.txt
Notice
the '%2F' at the beginning of the path to the file.
FILENAME:
absolute
or relative path to the filename to save downloaded file as
"""
import
urllib
import
sys
if
'-h' in sys.argv or '--help' in sys.argv:
    print
__doc__
    sys.exit(1)
if
not len(sys.argv) == 3:
    print
'URL and FILENAME are mandatory'
    print
__doc__
    sys.exit(1)
url
= sys.argv[1]
filename
= sys.argv[2]
urllib.urlretrieve(url,
filename)
运行示例：
#
./url_retrieve_urllib.py ftp://ftp.pku.edu.cn/welcome.msg
/root/wel.msg
urllib2做了扩展，支持更好的认证和cookies。
               
               
               
               
               

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