Minimalistic server

server.py

import io
import json
import http.server
import socketserver

HOST = "localhost"
PORT = 8080

class AnalyzerHandler(http.server.BaseHTTPRequestHandler):
  def do_POST(self):
    # Note that read() without content length may block indefinitely, because
    # not all clients send an EOF character.
    byte_data = self.rfile.read(int(self.headers.get("Content-Length")))
    data = json.loads(byte_data.decode("utf-8"))

    # Write headers.
    self.send_response(200)
    self.send_header("Content-Type", "application/json; charset=utf-8")
    self.end_headers()

    # Write output data. The option write_through=True prevents TextIOWrapper
    # from buffering internally, so that all data has been written to wfile when
    # it is detached.
    output = io.TextIOWrapper(self.wfile, encoding="utf-8", write_through=True)
    json.dump({"status": 200, "data": data}, output)

    # Detach so wfile won't be closed when output is cleaned up.
    # Note that wfile is flushed by BaseHTTPRequestHandler.
    output.detach()


# Allow immediate port re-use after termination.
socketserver.TCPServer.allow_reuse_address = True

# Open a TCP server with a handler derived from BaseHTTPRequestHandler.
with socketserver.TCPServer((HOST, PORT), AnalyzerHandler) as server:
  try:
    server.serve_forever()
  except KeyboardInterrupt:
    server.server_close()

I tried to implement streamed reading and writing of JSON data, but I only managed to get streamed writing using the built-in json.dump and an io.TextIOWrapper.