YTD HTTP Server

Kyler Olsen YTD HTTP Server

A simple HTTP server intended to work in micropython on a Raspberry Pi Pico W. Loosely inspired by http.server from the Python standard library.

Documentation

Also see windows_test.py and pico_test.py

First Import the HTTP_Server and HTTP_Request_Handler classes.

from ytd_http_server import HTTP_Server, HTTP_Request_Handler

The HTTP_Server class listens for requests and instantiates a Request Handler class to handle the request.

The HTTP_Request_Handler class reads and parses the request, and calls a member function to handle the request.

The member function called is determined by the http request method.

Method	Member Function	Short Method Description
HEAD	DO_HEAD	Same as GET but without response body
GET	DO_GET	Retrieve the resource at the given URI
PUT	DO_PUT	Put data at the given URI
POST	DO_POST	Put data at the given URI
DELETE	DO_DELETE	Delete the resource at the given URI

Any other method will result in DO_UNKNOWN being called. All of the functions just take the self parameter.

The difference between PUT and POST is that multiple identical PUT requests will have no affect following the first request, where as multiple identical POST requests will change something on the server with every request.

By default in the HTTP_Request_Handler class, each of these methods will return a 501 Not Implemented error. If we want to handle one of these methods, we need to overwrite the associated function by subclassing HTTP_Request_Handler.

Here is an example HTTP_Request_Handler subclass that serves all files on the filesystem. WARNING: Be careful doing it this way as it exposes all files on the filesystem to anyone with access to the http server.

class Custom_Request_Handler(HTTP_Request_Handler):

    def DO_GET(self):
        try:
            path = self.path
            if path[-1] == '/': path += 'index.html'
            with open(path[1:], 'rb') as file:
                self.set_status(200)
                data = file.read()
                self.set_header("Content-Length", str(len(data)))
                self.send_headers()
                self.send_body(data)
        except OSError:
            self.set_status(404)
            self.send_headers()

HTTP_Request_Handler.set_status sets the status code for the response. Examples: self.set_status(200), self.set_status('404 Not Found')

HTTP_Request_Handler.set_header sets a header in the response. Examples: self.set_header("Content-Length", str(len(data))), self.set_header("Content-Type", "text/html")

HTTP_Request_Handler.send_headers sends the response headers to the client. This includes the response code and all given headers. Example: self.send_headers()

HTTP_Request_Handler.send_body sends the body of the response. Not all responses need a body. The object given must be of type bytes (Other types may work but are not guaranteed). Examples: self.send_body(data), self.send_body("Hello World".encode('utf-8'))

HTTP_Request_Handler.body is the body of the request. Not all requests have a body, in which case HTTP_Request_Handler.body be an empty byte string. Example: data = self.body

Finally create an HTTP_Server object, passing in your Response Handler class. Then calling HTTP_Server.serve_forever will start the server, it will begin accepting requests, blocking code execution.

def main():
    server = HTTP_Server(Custom_Request_Handler)
    server.serve_forever()