Initial Commit

dev_server.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
+from io import BytesIO
+from pathlib import Path
+import argparse
+import errno
+import os
+import time
+
+
+ROOT = Path(__file__).resolve().parent
+WATCH_EXTENSIONS = {".html", ".css", ".js"}
+RELOAD_SNIPPET = """
+<script>
+(() => {
+  const events = new EventSource("/__hotreload");
+  events.addEventListener("reload", () => window.location.reload());
+})();
+</script>
+"""
+
+
+class HotReloadHandler(SimpleHTTPRequestHandler):
+    def end_headers(self):
+        self.send_header("Cache-Control", "no-store")
+        super().end_headers()
+
+    def do_GET(self):
+        if self.path == "/__hotreload":
+            self.handle_hotreload()
+            return
+
+        super().do_GET()
+
+    def translate_path(self, path):
+        clean_path = path.split("?", 1)[0].split("#", 1)[0].lstrip("/")
+        return str(ROOT / clean_path)
+
+    def send_head(self):
+        path = Path(self.translate_path(self.path))
+        if path.is_dir():
+            path = path / "index.html"
+
+        if path.suffix == ".html" and path.exists():
+            html = path.read_text(encoding="utf-8")
+            html = html.replace("</body>", f"{RELOAD_SNIPPET}</body>")
+            body = html.encode("utf-8")
+
+            self.send_response(200)
+            self.send_header("Content-Type", "text/html; charset=utf-8")
+            self.send_header("Content-Length", str(len(body)))
+            self.end_headers()
+            return BytesIO(body)
+
+        return super().send_head()
+
+    def handle_hotreload(self):
+        self.send_response(200)
+        self.send_header("Content-Type", "text/event-stream")
+        self.send_header("Cache-Control", "no-store")
+        self.send_header("Connection", "keep-alive")
+        self.end_headers()
+
+        last_seen = latest_mtime()
+        while True:
+            time.sleep(0.5)
+            current = latest_mtime()
+            if current > last_seen:
+                last_seen = current
+                try:
+                    self.wfile.write(b"event: reload\ndata: changed\n\n")
+                    self.wfile.flush()
+                except (BrokenPipeError, ConnectionResetError):
+                    break
+
+
+def latest_mtime():
+    latest = 0.0
+    for directory, names, files in os.walk(ROOT):
+        if ".git" in names:
+            names.remove(".git")
+
+        for filename in files:
+            path = Path(directory) / filename
+            if path.suffix in WATCH_EXTENSIONS:
+                latest = max(latest, path.stat().st_mtime)
+
+    return latest
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Run a tiny p5 dev server with hot reload.")
+    parser.add_argument("--host", default="0.0.0.0")
+    parser.add_argument("--port", type=int, default=8000)
+    args = parser.parse_args()
+
+    server, port = create_server(args.host, args.port)
+    print(f"Serving http://{args.host}:{port}", flush=True)
+    print("Watching .html, .css, and .js files for changes", flush=True)
+    server.serve_forever()
+
+
+def create_server(host, preferred_port):
+    for port in range(preferred_port, preferred_port + 20):
+        try:
+            return ThreadingHTTPServer((host, port), HotReloadHandler), port
+        except OSError as error:
+            if error.errno != errno.EADDRINUSE:
+                raise
+
+    raise OSError(f"No available port found from {preferred_port} to {preferred_port + 19}")
+
+
+if __name__ == "__main__":
+    main()