Lesson 2 - Step 2 of 5

Python's http.server

Learn to use Python's built-in HTTP server module.

How to Read Code Blocks

In this lesson:

Filename in header (e.g., simple_server.py) = Write this code to that file
bash blocks = Commands to run in your terminal
"Expected Output" = What you should see (don't write this)

The http.server Module

Python includes a fully-featured HTTP server in its standard library. No external dependencies needed! The key classes are:

HTTPServer — The server that listens for connections
BaseHTTPRequestHandler — Handles individual requests

Your First Server

Create a file called simple_server.py:

python

from http.server import HTTPServer, BaseHTTPRequestHandler


class SimpleHandler(BaseHTTPRequestHandler):
    """Handle HTTP requests."""

    def do_GET(self):
        """Handle GET requests."""
        # Send response status
        self.send_response(200)

        # Send headers
        self.send_header("Content-Type", "text/plain")
        self.end_headers()

        # Send body
        message = f"Hello! You requested: {self.path}"
        self.wfile.write(message.encode())


def run_server(port=8080):
    """Start the HTTP server."""
    server_address = ("localhost", port)
    httpd = HTTPServer(server_address, SimpleHandler)
    print(f"Server running on http://localhost:{port}")
    httpd.serve_forever()


if __name__ == "__main__":
    run_server()

Run the Server

bash

python simple_server.py

Then test it in another terminal:

bash

curl http://localhost:8080/test
# Output: Hello! You requested: /test

curl http://localhost:8080/any/path
# Output: Hello! You requested: /any/path

Understanding the Handler

The BaseHTTPRequestHandler provides several useful attributes:

python

class MyHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        # Request information
        print(f"Path: {self.path}")           # "/api/test"
        print(f"Headers: {self.headers}")     # All request headers
        print(f"Method: {self.command}")      # "GET"

        # Response methods
        self.send_response(200)               # Set status code
        self.send_header("Key", "Value")      # Add header
        self.end_headers()                    # Finish headers
        self.wfile.write(b"body")             # Write response body

HTTP Methods

Define methods for each HTTP verb you want to handle:

python

class MultiMethodHandler(BaseHTTPRequestHandler):

    def do_GET(self):
        """Handle GET requests."""
        self.send_response(200)
        self.send_header("Content-Type", "text/plain")
        self.end_headers()
        self.wfile.write(b"This is a GET response")

    def do_POST(self):
        """Handle POST requests."""
        self.send_response(200)
        self.send_header("Content-Type", "text/plain")
        self.end_headers()
        self.wfile.write(b"This is a POST response")

    def do_DELETE(self):
        """Handle DELETE requests."""
        self.send_response(200)
        self.send_header("Content-Type", "text/plain")
        self.end_headers()
        self.wfile.write(b"This is a DELETE response")

Method Naming

The method names must be do_GET, do_POST, etc. The framework automatically routes requests based on the HTTP method.