init commit

browser_cli/client.py

@@ -0,0 +1,61 @@
+"""
+Unix socket client — sends commands to the native host relay socket.
+Used by both the CLI and the public Python API.
+"""
+import json
+import socket
+import struct
+import uuid
+from typing import Any
+
+SOCKET_PATH = "/tmp/browser-cli.sock"
+
+
+class BrowserNotConnected(Exception):
+    """Raised when the native host socket is not available."""
+
+
+def send_command(command: str, args: dict | None = None) -> Any:
+    """Send a command to the browser and return the response data."""
+    msg = {
+        "id": str(uuid.uuid4()),
+        "command": command,
+        "args": args or {},
+    }
+    payload = json.dumps(msg).encode("utf-8")
+    framed = struct.pack("<I", len(payload)) + payload
+
+    try:
+        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
+            sock.connect(SOCKET_PATH)
+            sock.sendall(framed)
+            response = _recv_all(sock)
+    except (FileNotFoundError, ConnectionRefusedError, OSError):
+        raise BrowserNotConnected(
+            "Cannot connect to browser.\n"
+            "Make sure:\n"
+            "  1. The browser-cli extension is installed and enabled\n"
+            "  2. The native host is registered: uv run browser-cli install chrome\n"
+            "  3. Your browser is running"
+        )
+
+    result = json.loads(response)
+    if not result.get("success", True):
+        raise RuntimeError(result.get("error", "unknown error from browser"))
+    return result.get("data")
+
+
+def _recv_all(sock: socket.socket) -> bytes:
+    raw_len = _recv_exact(sock, 4)
+    msg_len = struct.unpack("<I", raw_len)[0]
+    return _recv_exact(sock, msg_len)
+
+
+def _recv_exact(sock: socket.socket, n: int) -> bytes:
+    buf = b""
+    while len(buf) < n:
+        chunk = sock.recv(n - len(buf))
+        if not chunk:
+            raise ConnectionError("Socket closed before full message received")
+        buf += chunk
+    return buf