Web Framework Nature

According to the socket we learned before, we can understand that all Web applications are essentially a socket server, and the user's browser is a socket client. This allows us to implement the web framework ourselves.

1. Custom Web framework for semi-finished products

Import socket

SK = Socket.socket (socket.af_inet,socket. SOCK_STREAM)

Sk.bind (("127.0.0.1", 80))

Sk.listen ()

While 1:

conn, addr = Sk.accept () # Establish connection

data = Conn.recv (8096) # Send and receive messages

Print (data) # Prints the message from the browser

Conn.send (b "Welcome") # Reply message

Conn.close ()

User's browser input URL, will send data to the server, what data will the browser send? How to send? Who's going to fix this?

At this time there is a unified rule, let everyone send messages, receive messages when there is a format basis, not casually write. This rule is the HTTP protocol, after the browser sends the request information, the server replies to the response information, should follow this rule.

The HTTP protocol mainly specifies the communication format between the client and the server, how does the HTTP protocol specify the message format? Look at the data we printed out.

B ' get/http/1.1\r\nhost:127.0.0.1:8080\r\nconnection:keep-alive\r\npragma:no-cache\r\ncache-control:no-cache\r\ nupgrade-insecure-requests:1\r\nuser-agent:mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) applewebkit/537.36 (khtml, like Gecko) chrome/65.0.3325.181 Safari/537.36\r\naccept:text/html,ap Plication/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8\r\naccept-encoding:gzip, deflate, br\r \naccept-language:zh-cn,zh;q=0.9,en;q=0.8\r\n\r\n '

2. XXX Version Custom Web frame

Import socket

Server=socket.socket (Socket.af_inet,socket. SOCK_STREAM)

Server.bind (("127.0.0.1", 8080))

Server.listen (5)

While 1:

Conn,addr=server.accept ()

DATA=CONN.RECV (1024)

Print (data)

Conn.send (b "http/1.1 ok\r\n\r\n") # Add response status line to reply message

Conn.send (b "Welcome")

Conn.close ()

3. Implement different paths to return different content

3.1 The low version

Import socket

Server = Socket.socket (socket.af_inet,socket. SOCK_STREAM)

Server.bind (("127.0.0.1", 8082))

Server.listen (5)

While 1:

CONN,ADDR = Server.accept ()

data = CONN.RECV (1024)

Data_str = str (data,encoding= "Utf-8")

url = data_str.split ("\ r \ n") [0].split () [1]

If url = = '/index ':

msg = B "This is index HTML"

Elif url = = '/home ':

msg = B "This is home HTML"

Else

msg = b "404 Not Found!!!"

Conn.send (b "http/1.1 ok\r\n\r\n")

Conn.send (msg)

Conn.close ()

3.2 Function Edition

Import socket

Server = Socket.socket (socket.af_inet,socket. SOCK_STREAM)

Server.bind (("127.0.0.1", 8082))

Server.listen (5)

def index (URL):

Return B "This is index HTML"

def home (URL):

Return B "This is home HTML"

While 1:

CONN,ADDR = Server.accept ()

data = CONN.RECV (1024)

Data_str = str (data,encoding= "Utf-8")

url = data_str.split ("\ r \ n") [0].split () [1]

If url = = '/index ':

msg = index (URL)

Elif url = = '/home ':

msg = Home (URL)

Else

msg = b "404 Not Found!!!"

Conn.send (b "http/1.1 ok\r\n\r\n")

Conn.send (msg)

Conn.close ()

3.3 Function Step

Import socket

Server = Socket.socket (socket.af_inet,socket. SOCK_STREAM)

Server.bind (("127.0.0.1", 8082))

Server.listen (5)

def index (URL):

Return B "This is index HTML"

def home (URL):

Return B "This is home HTML"

Url_list = [

("/index", Index),

("Home",

] # defines the correspondence between a URL and the actual function to be executed

While 1:

CONN,ADDR = Server.accept ()

data = CONN.RECV (1024)

Data_str = str (data,encoding= "Utf-8")

url = data_str.split ("\ r \ n") [0].split () [1]

func = None # Defines a variable that holds the name of the function that will be executed

For I in Url_list:

If i[0] = = URL:

Func = i[1]

Break

If Func:

msg = func (URL)

Else

msg = b "404 Not Found!"

Conn.send (b "http/1.1 ok\r\n\r\n")

Conn.send (msg)

Conn.close ()

Web Framework Nature