status-indicators/push_page.py

#!/usr/bin/env python3
"""Import the status page (19) or the Restart page (20; both numbers come from config.json) into Companion without clicking through the UI.

Does exactly what Import/Export -> Import -> "import into page N" does, over the
same internal API the Companion web UI uses (tRPC over a WebSocket at /trpc):
upload the file in chunks, check its SHA-1, then import it as a single page.

Safety: it looks at what is on the target page, not just its name. It refuses unless the
page holds nothing but page up / page number / page down keys, or is already the page this
file builds (same name). A page named "PAGE" can still hold real buttons (pages 22 and 97 do).

  python3 push_page.py                         # the status page, from config.json
  python3 push_page.py --which restart         # the Restart page
  python3 push_page.py --host 10.6.3.222 --page 19 --file status-page.companionconfig

Stdlib only (a minimal WebSocket client is included). Written against Companion 5.0.7.
"""
import argparse
import base64
import gzip
import hashlib
import json
import os
import socket
import struct
import sys
import time
import urllib.parse
import urllib.request

HERE = os.path.dirname(os.path.abspath(__file__))
CHUNK = 256 * 1024


class WebSocket:
    def __init__(self, host, port, path, timeout=15):
        self.sock = socket.create_connection((host, port), timeout=timeout)
        key = base64.b64encode(os.urandom(16)).decode()
        self.sock.sendall(("GET %s HTTP/1.1\r\nHost: %s:%d\r\nUpgrade: websocket\r\nConnection: Upgrade\r\n"
                           "Sec-WebSocket-Key: %s\r\nSec-WebSocket-Version: 13\r\n\r\n"
                           % (path, host, port, key)).encode())
        buf = b""
        while b"\r\n\r\n" not in buf:
            chunk = self.sock.recv(4096)
            if not chunk:
                raise ConnectionError("connection closed during WebSocket handshake")
            buf += chunk
        head, self.buf = buf.split(b"\r\n\r\n", 1)
        if b" 101 " not in head.split(b"\r\n", 1)[0]:
            raise ConnectionError("WebSocket handshake refused: %s" % head.split(b"\r\n", 1)[0].decode())

    def _read(self, n):
        while len(self.buf) < n:
            chunk = self.sock.recv(65536)
            if not chunk:
                raise ConnectionError("connection closed")
            self.buf += chunk
        data, self.buf = self.buf[:n], self.buf[n:]
        return data

    def _send(self, opcode, payload):
        n = len(payload)
        header = bytes([0x80 | opcode])
        if n < 126:
            header += bytes([0x80 | n])
        elif n < 65536:
            header += bytes([0x80 | 126]) + struct.pack(">H", n)
        else:
            header += bytes([0x80 | 127]) + struct.pack(">Q", n)
        mask = os.urandom(4)
        masked = bytes(b ^ mask[i & 3] for i, b in enumerate(payload))
        self.sock.sendall(header + mask + masked)

    def send(self, text):
        self._send(0x1, text.encode())

    def recv(self):
        message = b""
        while True:
            b1, b2 = self._read(2)
            fin, opcode, n = b1 & 0x80, b1 & 0x0F, b2 & 0x7F
            if n == 126:
                n = struct.unpack(">H", self._read(2))[0]
            elif n == 127:
                n = struct.unpack(">Q", self._read(8))[0]
            payload = self._read(n)
            if opcode == 0x9:                       # ping
                self._send(0xA, payload)
                continue
            if opcode == 0x8:
                raise ConnectionError("server closed the WebSocket")
            message += payload
            if fin:
                return message.decode()

    def close(self):
        try:
            self._send(0x8, b"")
        finally:
            self.sock.close()


class Trpc:
    def __init__(self, ws):
        self.ws, self.next_id = ws, 1

    def mutation(self, path, data):
        rid = self.next_id
        self.next_id += 1
        self.ws.send(json.dumps({"id": rid, "jsonrpc": "2.0", "method": "mutation",
                                 "params": {"path": path, "input": data}}))
        while True:
            msg = json.loads(self.ws.recv())
            if msg.get("id") != rid:
                continue
            if "error" in msg:
                err = msg["error"]
                raise RuntimeError("%s failed: %s" % (path, err.get("message", err)))
            return msg.get("result", {}).get("data")


NAV_TYPES = ("pageup", "pagedown", "pagenum")
NAV_MARKER = "STATUS nav key"          # our coloured page number key (make_page.nav_key)


def fetch_page(host, port, page):
    """The page as Companion exports it ({"page": {"name", "controls": {row: {col: control}}}})."""
    with urllib.request.urlopen("http://%s:%d/int/export/page/%d" % (host, port, page), timeout=10) as r:
        raw = r.read()
    try:
        raw = gzip.decompress(raw)
    except OSError:
        pass
    return json.loads(raw)


def real_buttons(export):
    """How many buttons a page holds besides its page up / number / down keys."""
    page = export.get("page") or {}
    n = 0
    for row in (page.get("controls") or {}).values():
        for ctl in (row or {}).values():
            if not ctl or ctl.get("type") in NAV_TYPES:
                continue
            if NAV_MARKER in ((ctl.get("options") or {}).get("notes") or ""):
                continue
            n += 1
    return n


def safe_target(export, expected_name):
    """(ok, reason). OK only for a page with nothing but nav keys, or the page this file builds."""
    name = ((export.get("page") or {}).get("name") or "")
    if name == expected_name:
        return True, "it is already %r" % name
    n = real_buttons(export)
    if n == 0:
        return True, "it holds only page keys"
    return False, "it is called %r and holds %d buttons" % (name, n)


def page_name(host, port, page):
    url = "http://%s:%d/api/variable/internal/page_number_%d_name/value" % (host, port, page)
    with urllib.request.urlopen(url, timeout=5) as r:
        return r.read().decode()


def main():
    cfg = json.load(open(os.path.join(HERE, "config.json")))
    ap = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    ap.add_argument("--which", choices=("status", "restart"), default="status")
    ap.add_argument("--host", default="na-ingest.local")
    ap.add_argument("--port", type=int, default=8000)
    ap.add_argument("--page", type=int)
    ap.add_argument("--file")
    ap.add_argument("--force", action="store_true", help="overwrite the page whatever is on it")
    args = ap.parse_args()
    if args.which == "restart":
        page, expected = cfg["restart_page"]["page"], cfg["restart_page"]["page_name"]
        default_file = "restart-page.companionconfig"
    else:
        page, expected, default_file = cfg["page"], cfg["page_name"], "status-page.companionconfig"
    args.page = args.page or page
    args.file = args.file or os.path.join(HERE, default_file)

    data = open(args.file, "rb").read()
    built = json.loads(gzip.decompress(data))
    if (built.get("page") or {}).get("name") != expected:
        sys.exit("%s builds page %r, not %r; refusing" % (os.path.basename(args.file),
                                                          (built.get("page") or {}).get("name"), expected))
    ok, why = safe_target(fetch_page(args.host, args.port, args.page), expected)
    if not ok and not args.force:
        sys.exit("page %d: %s - refusing (use --force only if you mean to replace it)" % (args.page, why))
    plain = page_name(args.host, args.port, args.page).replace("\\n", " ").strip()
    ws = WebSocket(args.host, args.port, "/trpc")
    try:
        api = Trpc(ws)
        # Only one upload at a time; an abandoned one expires after a short idle time.
        for attempt in range(40):
            try:
                session = api.mutation("importExport.prepareImport.start",
                                       {"name": os.path.basename(args.file), "size": len(data)})
                break
            except RuntimeError as e:
                if "already exists" not in str(e) or attempt == 39:
                    raise
                if attempt == 0:
                    print("another upload is still open in Companion; waiting for it to expire...")
                time.sleep(3)
        for offset in range(0, len(data), CHUNK):
            api.mutation("importExport.prepareImport.uploadChunk",
                         {"sessionId": session, "offset": offset,
                          "data": base64.b64encode(data[offset:offset + CHUNK]).decode()})
        summary = api.mutation("importExport.prepareImport.complete",
                               {"sessionId": session, "expectedChecksum": hashlib.sha1(data).hexdigest(),
                                "userData": None})
        if isinstance(summary, list) and summary and summary[0]:
            sys.exit("Companion could not read the file: %s" % summary[0])
        api.mutation("importExport.importSinglePage",
                     {"targetPage": args.page, "sourcePage": 1, "connectionIdRemapping": {}})
    finally:
        ws.close()
    print("imported %s into page %d (was %r, now %r)" % (os.path.basename(args.file), args.page, plain,
                                                         page_name(args.host, args.port, args.page)))


if __name__ == "__main__":
    main()