Lære Sending Structured Data | Working with Sockets

When computers exchange information, plain text is often not enough, so we use structured data that both sides can easily understand. The most common format is JSON, which is readable, lightweight, and maps naturally to Python dictionaries and lists.

Common structured data formats:

JSON, widely used in web APIs and modern applications;
XML, more verbose but still used in some systems;
CSV, simple format mainly for tabular data.


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import socket
import json

# Data to send (a Python dictionary)
data = {
    "username": "alice",
    "score": 42,
    "active": True
}

# Serialize dictionary to JSON string, then encode to bytes
json_data = json.dumps(data).encode("utf-8")

# Set up a server socket (for demonstration)
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("localhost", 65432))
server.listen(1)

# Set up a client socket
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(("localhost", 65432))

# Accept connection on the server side
conn, addr = server.accept()

# Client sends JSON data
client.sendall(json_data)

# Server receives data
received = conn.recv(1024)
# Decode bytes to string, then deserialize JSON to dictionary
received_data = json.loads(received.decode("utf-8"))

print("Server received:", received_data)

# Clean up sockets
client.close()
conn.close()
server.close()

The process you just saw, serialization and deserialization, is fundamental to sending structured data over a network. Serialization means converting a Python object, such as a dictionary, into a format that can be transmitted as bytes over a socket, typically a JSON string encoded into bytes.

On the receiving side, deserialization reverses this process by decoding the bytes back into a string and converting it into a Python object using json.loads. This allows complex data to be exchanged reliably between different programs, machines, or even different programming languages, making your network communication more flexible and extensible.

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Common structured data formats:

JSON, widely used in web APIs and modern applications;
XML, more verbose but still used in some systems;
CSV, simple format mainly for tabular data.


              123456789101112131415161718192021222324252627282930313233343536373839
            
import socket
import json

# Data to send (a Python dictionary)
data = {
    "username": "alice",
    "score": 42,
    "active": True
}

# Serialize dictionary to JSON string, then encode to bytes
json_data = json.dumps(data).encode("utf-8")

# Set up a server socket (for demonstration)
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("localhost", 65432))
server.listen(1)

# Set up a client socket
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(("localhost", 65432))

# Accept connection on the server side
conn, addr = server.accept()

# Client sends JSON data
client.sendall(json_data)

# Server receives data
received = conn.recv(1024)
# Decode bytes to string, then deserialize JSON to dictionary
received_data = json.loads(received.decode("utf-8"))

print("Server received:", received_data)

# Clean up sockets
client.close()
conn.close()
server.close()

Var alt klart?

Tak for dine kommentarer!

Sektion 2. Kapitel 4