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Python Internet

Python Socket

refer: https://docs.python.org/2/library/socket.html

Echo Server and Client

Simple Echo Server and Client

Echo Server

# Echo server program
import socket
 
HOST = ''                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
print 'server is listening'
conn, addr = s.accept()
print 'Connected by', addr
while 1:
    data = conn.recv(1024)
    if not data: break
    conn.sendall(data)
conn.close()

output:

server is listening

Echo Client

# Echo client program
import socket
 
HOST = '127.0.0.1'    # The remote host
PORT = 50007              # The same port as used by the server
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('Hello, world')
data = s.recv(1024)
s.close()
print 'Received', repr(data)

server output:

server is listening
Connected by ('127.0.0.1', 56354)

client output:

Received 'Hello, world'

Custom Echo Server for multiple client

The above example only service for 1 client, after the server receive connection and send data to client, the echoserver program will end. The below example will service for multiple clients

Echo server

# Echo server program
import socket
 
HOST = ''                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(10)
print 'server is listening'
while 1:
    conn, addr = s.accept()
    print 'Connected by', addr
    data = conn.recv(1024)
    if not data: break
    conn.sendall(data)
conn.close()

Connect to google with socket and receive data

#Socket client example in python
 
import socket   #for sockets
import sys  #for exit
 
#create an INET, STREAMing socket
try:
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error:
    print 'Failed to create socket'
    sys.exit()
 
print 'Socket Created'
 
host = 'www.google.com';
port = 80;
 
try:
    remote_ip = socket.gethostbyname( host )
 
except socket.gaierror:
    #could not resolve
    print 'Hostname could not be resolved. Exiting'
    sys.exit()
 
#Connect to remote server
s.connect((remote_ip , port))
 
print 'Socket Connected to ' + host + ' on ip ' + remote_ip
 
#Send some data to remote server
message = "GET / HTTP/1.1\r\n\r\n"
 
try :
    #Set the whole string
    s.sendall(message)
except socket.error:
    #Send failed
    print 'Send failed'
    sys.exit()
 
print 'Message send successfully'
 
#Now receive data
reply = s.recv(4096)
 
print reply

output

Socket Created
Socket Connected to www.google.com on ip 125.235.30.157
Message send successfully
HTTP/1.1 302 Found
Cache-Control: private
Content-Type: text/html; charset=UTF-8
Location: http://www.google.com.vn/?gfe_rd=cr&ei=Cd_gU72uKIiK8Qe6koDICQ
Content-Length: 262
Date: Tue, 05 Aug 2014 13:41:29 GMT
Server: GFE/2.0
Alternate-Protocol: 80:quic

<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.com.vn/?gfe_rd=cr&amp;ei=Cd_gU72uKIiK8Qe6koDICQ">here</A>.
</BODY></HTML>

httplib and urllib2

The basic class for processing http is httplib package
urllib2 is a Python module that can be used for fetching URLs. It defines functions and classes to help with URL actions (basic and digestauthentication, redirections, cookies, etc). urllib2 handle object types below:
```
default_classes = [ProxyHandler, UnknownHandler, HTTPHandler,
                       HTTPDefaultErrorHandler, HTTPRedirectHandler,
                       FTPHandler, FileHandler, HTTPErrorProcessor]
```
With http, urllib2 using httplib for sending and receiving data

urllib2.urlopen return addinfourl and debug send data in request

addinfourl have basic methods below:

class addinfourl(addbase):
    """class to add info() and geturl() methods to an open file."""
 
    def __init__(self, fp, headers, url, code=None):
        addbase.__init__(self, fp)
        self.headers = headers
        self.url = url
        self.code = code
 
    def info(self):
        return self.headers
 
    def getcode(self):
        return self.code
 
    def geturl(self):
        return self.url

debug send data in request: Edit send function in httplib.HTTPConnection:

    def send(self, data):
        """Send `data' to the server."""
...............................
        else:
            self.sock.sendall(data)
            print data

and other methods the same read and write file such as read, readlines, next, close

class addbase:
    """Base class for addinfo and addclosehook."""
 
    def __init__(self, fp):
        self.fp = fp
        self.read = self.fp.read
        self.readline = self.fp.readline
        if hasattr(self.fp, "readlines"): self.readlines = self.fp.readlines
        if hasattr(self.fp, "fileno"):
            self.fileno = self.fp.fileno
        else:
            self.fileno = lambda: None
        if hasattr(self.fp, "__iter__"):
            self.__iter__ = self.fp.__iter__
            if hasattr(self.fp, "next"):
                self.next = self.fp.next
 
    def __repr__(self):
        return '<%s at %r whose fp = %r>' % (self.__class__.__name__,
                                             id(self), self.fp)
 
    def close(self):
        self.read = None
        self.readline = None
        self.readlines = None
        self.fileno = None
        if self.fp: self.fp.close()
        self.fp = None

simple request(GET)

Simple request with httplib

import httplib
url = 'www.python.org'
conn = httplib.HTTPConnection(url)
conn.request('GET', '')
res = conn.getresponse()
print res.status, res.reason
print res.read()

⇒ output:

301 Moved Permanently

Simple request with urllib2:

import urllib2
response = urllib2.urlopen('http://www.python.org')
print response.read()

or

import urllib2
req = urllib2.Request('http://www.python.org')
response = urllib2.urlopen(req)
print response.read()

⇒ response is urllib.addinfourl object and output are full html data

simple post

POST with httplib

import httplib, urllib
params = urllib.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
conn = httplib.HTTPConnection("bugs.python.org")
conn.request("POST", "", params, headers)
response = conn.getresponse()
print response.status, response.reason
data = response.read()
print data
conn.close()

output:

302 Found
Redirecting to <a href="http://bugs.python.org/issue12524">http://bugs.python.org/issue12524</a>

POST with urllib2

import urllib, urllib2
params = urllib.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
req = urllib2.Request("http://bugs.python.org", data = params, headers = headers)
response = urllib2.urlopen(req)
data = response.read()
print data

⇒ Output with full html data

urllib2.build_opener(replace urlopen) and post with cookies

Using build_opener for sending request:

import urllib2
 
opener = urllib2.build_opener(urllib2.HTTPHandler()) 
response = opener.open('http://www.python.org')
print response.read()

and for sending post:

import urllib, urllib2
params = urllib.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
req = urllib2.Request("http://bugs.python.org", data = params, headers = headers)
 
opener = urllib2.build_opener(urllib2.HTTPHandler()) 
response = opener.open(req)
print 'headers:', response.info()
print response.read()

output:

headers: Date: Wed, 06 Aug 2014 04:01:39 GMT
Server: BaseHTTP/0.3 Python/2.6.6
Expires: Wed, 06 Aug 2014 04:01:38 GMT
Content-Type: text/html; charset=utf-8
Cache-Control: no-cache
Via: 1.1 bugs.python.org
Connection: close
Transfer-Encoding: chunked

Send normal login to OpenCart:

import urllib, urllib2
 
loginurl = 'http://dacsan.babies.vn/index.php?route=account/login'
params = urllib.urlencode({'email': '[email protected]', 'password':'8941362', 'redirect':'http://dacsan.babies.vn/index.php?route=account/account'})
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
req = urllib2.Request(loginurl, data = params, headers = headers)
response = urllib2.urlopen(req)
print 'headers:', response.info()
data = response.read()
with open('loginresult.html', 'wb') as f:
    f.write(data)

Send login to OpenCart with cookies header:

import urllib, urllib2
 
loginurl = 'http://dacsan.babies.vn/index.php?route=account/login'
params = urllib.urlencode({'email': '[email protected]', 'password':'8941362', 'redirect':'http://dacsan.babies.vn/index.php?route=account/account'})
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
req = urllib2.Request(loginurl, data = params, headers = headers)
 
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor()) 
response = opener.open(req)
 
data = response.read()
with open('loginresult.html', 'wb') as f:
    f.write(data)

my notes

Table of Contents

Python Internet

Python Socket

Echo Server and Client

Simple Echo Server and Client

Custom Echo Server for multiple client

Connect to google with socket and receive data

httplib and urllib2

urllib2.urlopen return addinfourl and debug send data in request

simple request(GET)

simple post

urllib2.build_opener(replace urlopen) and post with cookies