Python#Network Connections -1

このページは個人的にPython勉強のメモです。今回はNetwork Connectionsについて話ししたいと思います。まずは覚えて置かないといけないの単語が幾つありますね。

Communication end point−Socketsのこと。
AF_INET−IPV4のこと（Address Family internet)
IP AddressとPort−例えの話になると、IP Addressはあなたが住んでるデパートでPortはあなたが住んでる部屋番号です。

2種類の通信方法があります。

Connection-oriented

電話通信みたいにちゃんと接続確認してからコミュニケーションする。
TCP[SOCK_STREAM]

Connectionless

接続確認なしで。

Server

あるもの（Hardware/Software)であるサービスを”Client”へ提供するってこと。Clientのリクエスト待ちと返信する。

Client

Serverへリクエストを送ってデータとかもらうっものです。

Hardwareの例え…

PrinterがはServerでパソコンはClientでFile Print！というリクエストが送る、Printerはこれを答えてPrintしたりします。

Softwareの例え…

WebServerで色々な人がパソコンを通じてWEB、WEB Applicationをアクセスします。Serverはこれに答えてWEBの情報などなど返しします。

Code Example In TCP

Server Side-

#Create a TCP Server
#Lower-level networking interface
#Using socket
from socket import*
from time import ctime

#Create a socket object from the given address family, 
#socket type, and protocol type (optional)

#an indication to the build() methond that can be using any addresss
#a random port that the system is not using
#the data size
host=''          
port=21567     
buff=1024       
add=(host,port)

tcpServerSocket=socket(AF_INET,SOCK_STREAM)     #socket moudle method for create a TCP/IP connections
tcpServerSocket.bind(add)       #Bind address(host,port)
tcpServerSocket.listen(5)       #Setup the TCP listener

while True: #infinite loop,waiting connection
    #the first loop,
    print ('waiting for connection....')
    tcpCliSock,add = tcpServerSocket.accept() #accept TCP clint connections
    print ('Connected from...',add)

    while True:
        data=tcpCliSock.recv(buff)
        if not data:#break loop while blank is sent
            break
        Message=('Received!'+ctime())
        print('Data Received: ',data.decode('utf-8'))
        print(ctime())
        MessageInBytes=bytes(Message,'utf-8')
        tcpCliSock.send(MessageInBytes)
    tcpCliSock.close()
tcpServerSocket.close()
print('The connection is closed.')

Client Side-

from socket import *

host='localhost'
port=21567
buff=1024
Addr=(host,port)

tcpCliSock=socket(AF_INET,SOCK_STREAM)
tcpCliSock.connect(Addr)

while True:
    data = input('> ')
    if not data:
        break
    dataInBytes=bytes(data,'utf-8')

    tcpCliSock.send(dataInBytes)

    AnsInBytes=tcpCliSock.recv(buff)
    if not data:
        break
    print(AnsInBytes.decode('utf-8'))
tcpCliSock.close()

Result:

[php]Server
waiting for connection….[/php]

[php]Client> HELLO[/php]

[php]Server
Connected from… (‘127.0.0.1’, 61439)
Data Received:  HELLO
Sun Dec 25 09:02:19 2016[/php]

[php]Client
Received!Sun Dec 25 09:02:19 2016[/php]

Code Example UDT

Server Side-

#Server Side in UDP
from socket import *
from time import  ctime

host=''
port=3000
buff=1024
addr=(host,port)

udtServer=socket(AF_INET,SOCK_DGRAM)
udtServer.bind(addr)
try:
    while True:
        print("Waiting the message...")
        data,addr=udtServer.recvfrom(buff)
        Message = ('Received!' + ctime())
        MessageInBytes = bytes(Message, 'utf-8')
        udtServer.sendto(MessageInBytes,addr)
        print ('Data is send to...',addr)
    udtServer.close()
except(KeyboardInterrupt,EOFError):
    print('Servies is out..')
    udtServer.close()

Client Side-

#UDP Client
from socket import  *

host='localhost'
port=3000
Buff=1024
addr=(host,port)

updClient=socket(AF_INET,SOCK_DGRAM)

while True:
    try:
        data=input('> ')
        if not data:
            break
        dataInBytes = bytes(data, 'utf-8')
        updClient.sendto(dataInBytes,addr)
        dataInBytes,addr=updClient.recvfrom(Buff)

        if not dataInBytes:
            break
        print (dataInBytes)
    except (KeyboardInterrupt,EOFError):
        print("out of services")
        break
updClient.close()

Result

[php]Server
Waiting the message…[/php]

[php]Client
> HELLO[/php]

[php]Server
Data is send to… (‘127.0.0.1’, 52293)
Waiting the message..[/php]

[php]Client
b’Received!Sun Dec 25 09:04:57 2016′[/php]

socketserver code example

Server side-

#UDP Client
from socket import  *

host='localhost'
port=3000
Buff=1024
addr=(host,port)

updClient=socket(AF_INET,SOCK_DGRAM)

while True:
    try:
        data=input('> ')
        if not data:
            break
        dataInBytes = bytes(data, 'utf-8')
        updClient.sendto(dataInBytes,addr)
        dataInBytes,addr=updClient.recvfrom(Buff)

        if not dataInBytes:
            break
        print (dataInBytes)
    except (KeyboardInterrupt,EOFError):
        print("out of services")
        break
updClient.close()

Client Side

#Socketserver TCP Client

from socket import *

#Basic client code
host='localhost'
port=3000
buff=1024
addr=(host,port)

while True:
    TcpClient=socket(AF_INET,SOCK_STREAM)
    TcpClient.connect(addr)
    data=input('> ')
    if not data:
        break
    data=data+'\n'
    print (data)
    dataInBytes = bytes(data,'utf-8')
    TcpClient.send(dataInBytes)
    data=TcpClient.recv(buff)
    if not data:
        break
    print (data)
    TcpClient.close()

Result

[php]Server:
waiting …[/php]

[php]Client:
HELLO[/php]

[php]Server:
waiting …
Connect from.. (‘127.0.0.1’, 61454)
get
b’HELLO\n'[/php]

[php]Client:
b’Received! :)Sun Dec 25 09:10:14 2016′[/php]