watcher.py

#!/usr/bin/env python3
import http.server
import socketserver
import threading
from urllib.parse import urlparse
from math import sqrt
import time
import pyvips
import ssl

counter = 0

#creates a jpeg image as bytes
def image_from_counter(counter):
	svg = ""
	svg += '''<?xml version="1.0" encoding="UTF-8"?>'''
	svg += '''<svg width="123mm" height="42mm" version="1.1" viewBox="0 0 123 42" xmlns="http://www.w3.org/2000/svg">'''
	svg += '''<g transform="translate(7.3 -241)" fill="#eaf" font-weight="bold" stroke-dasharray="5.55624993, 2.77812495999999998" stroke-linecap="round" stroke-linejoin="round" stroke-miterlimit="10" stroke-width="2.8">'''
	svg += f'''<text x="2.4973986" y="260.90326" font-family="sans" font-size="14px" style="text-align:start;text-anchor:start;line-height:1.25;paint-order:stroke fill markers" xml:space="preserve"><tspan x="0" y="260.90326" font-family="FreeSans" font-size="14px" font-weight="bold" stroke-width="2.8">{counter} {"person" if counter==1 else "people"}</tspan></text>'''
	svg += f'''<text x="3.2082679" y="271.4866" font-family="FreeSans" font-size="4.6px" style="text-align:start;text-anchor:start;line-height:1.25;paint-order:stroke fill markers" xml:space="preserve"><tspan x="0" y="271.4866" font-size="5.6px" stroke-width="2.8">{"is" if counter==1 else "are"} currently looking at this image</tspan></text>'''
	svg += '''</g>'''
	svg += '''</svg>'''
	image = pyvips.Image.new_from_buffer(svg.encode('utf8'),"")
	return image.write_to_buffer('.jpg[Q=20]')

class MyHttpRequestHandler(http.server.SimpleHTTPRequestHandler):
	def do_GET(self):
		global counter
		parsedpath = urlparse(self.path)
		self.was_stream = False
		if parsedpath.path == '/stream.mjpeg':
			counter += 1
			self.was_stream = True
			self.send_response(200)
			self.send_header("Content-type", "multipart/x-mixed-replace; boundary=--myboundary")
			self.send_header("Cache-Control", "no-store, must-revalidate")
			self.send_header("Pragma", "no-cache")
			self.send_header("Expires", "0")
			self.end_headers()
			loops = 0
			while True:
				loops += 1
				data = image_from_counter(counter)
				sep = f'''--myboundary\r\nContent-Type: image/jpeg\r\nContent-Length: {len(data)}\r\n\r\n'''
				self.wfile.write(sep.encode('utf8'))
				self.wfile.write(data)
				self.wfile.flush()
				if loops > 2:
					time.sleep(5)
				else:
					time.sleep(.1)
		else:
			self.send_response(400)
	def __del__(self):
		global counter
		if self.was_stream == True:
			counter -= 1
			print("done")

class ThreadingSimpleServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
	pass

if __name__ == "__main__":
	socketserver.TCPServer.allow_reuse_address = True
	server = ThreadingSimpleServer(("", 42069), MyHttpRequestHandler)
	server.socket = ssl.wrap_socket (server.socket, keyfile="./key.pem", certfile='./cert.pem', server_side=True)
	server.serve_forever()