Files
codex-app-server/cloud/playwright_browser.py
T
host fafc0734c7 perf: screencast 隔帧改每帧,跟手优先
Page.startScreencast everyNthFrame 2 -> 1,画质 q60、尺寸
1280x800 不动。静态页不产生额外成本(帧只在重绘时来,
且 #187 起桥只写变化的帧字节);收益全部落在真正需要跟
手的时候:滚动、拖拽、动画期间帧率翻倍。测试断言同步。
2026-10-30 13:50:18 +08:00

591 lines
22 KiB
Python

"""Headless Chromium automation for Codex tasks, via Playwright.
One Browser object owns one page for the lifetime of an MCP
process. It is deliberately small: navigate, snapshot (page text),
click, fill, evaluate, screenshot, close. Anything fancier the
agent can do with the shell tool, which has the same sandbox
privileges as this browser (tenant Docker container, egress
proxy whitelist).
Browser launch facts that matter in production (verified
2026-10-30 in a runsc + user 1003 + docker-codex AppArmor
container, the same shape as a production Docker task):
- Chromium must run --no-sandbox (rootless container user, no
userns sandbox) and --disable-dev-shm-usage (small /dev/shm).
- Browsers live at PLAYWRIGHT_BROWSERS_PATH=/opt/ms-playwright
in the image (the build installs them there, NOT in a home
directory, because the container user has no home and the
build ran as root).
- Network goes through the egress proxy when HTTP_PROXY /
HTTPS_PROXY is set in the MCP env (worker writes it from
proxy_env, same as websearch): Playwright gets an explicit
proxy server, because Chromium does not reliably pick up env
proxies on Linux. Domains outside the Tinyproxy whitelist
then fail with a proxy 403, which the tool reports plainly
instead of bypassing.
- Screenshots and downloads land in the working directory
(the task worktree), never outside it.
"""
import json
import os
import time
BROWSERS_PATH = "/opt/ms-playwright"
SNAPSHOT_LIMIT = 8000
NAV_TIMEOUT_MS = 60000
class BrowserError(RuntimeError):
pass
def _validate_basename(name, what):
if (not name or os.path.basename(name) != name or name in (".", "..")
or "/" in name or "\\" in name):
raise BrowserError(
"%s must be a plain basename, got %r" % (what, name))
return name
class Browser:
"""A single Chromium page. ``browser_factory`` is injectable:
tests pass a fake returning a fake sync_playwright object."""
def __init__(self, cwd=None, proxy=None, browser_factory=None):
self.cwd = os.path.abspath(cwd or os.getcwd())
self.proxy = (proxy or os.environ.get("HTTPS_PROXY")
or os.environ.get("HTTP_PROXY") or "")
self._factory = browser_factory
self._pw = None
self._browser = None
self._page = None
self._current_url = ""
self._last_title = ""
# ref snapshot state (playwright-mcp style): ref -> css path
self._ref_paths = {}
# screencast sink: a queue.Queue set by the remote service.
# The CDP frame callback only enqueues; the MCP main thread
# drains it (pump_screencast) because Playwright sync calls
# must run on the thread that created the page.
self._frame_sink = None
self._cdp = None
self._cdp_page = None
def _ensure(self):
if self._page is not None:
return
try:
if self._factory is not None:
pw = self._factory()
if hasattr(pw, "start"):
pw = pw.start()
else:
from playwright.sync_api import sync_playwright
pw = sync_playwright().start()
launch = {"args": ["--no-sandbox",
"--disable-dev-shm-usage",
"--disable-gpu"]}
if self.proxy:
launch["proxy"] = {"server": self.proxy}
browser = pw.chromium.launch(**launch)
page = browser.new_page(
viewport={"width": 1280, "height": 800})
except Exception as exc: # noqa: BLE001 - surfaced as tool error
raise BrowserError("browser launch failed: %s" % exc)
self._pw = pw
self._browser = browser
self._page = page
def _info(self):
try:
title = self._page.title()
except Exception: # noqa: BLE001 - title is best-effort
title = ""
self._last_title = title
return {"url": self._current_url, "title": title}
def cached_info(self):
"""Plain-attribute state, safe to read from any thread
(the remote HTTP thread must never call page.title())."""
return {"url": self._current_url, "title": self._last_title,
"started": self._page is not None}
def navigate(self, url):
if not url or not str(url).strip():
raise BrowserError("url is required")
self._ensure()
try:
self._page.goto(str(url), timeout=NAV_TIMEOUT_MS,
wait_until="domcontentloaded")
self._current_url = self._page.url
self._start_screencast()
self._eager_frame()
except Exception as exc: # noqa: BLE001
raise BrowserError("navigate failed: %s" % exc)
result = self._info()
result["ok"] = True
return result
def snapshot(self):
self._ensure()
try:
text = self._page.locator("body").inner_text(timeout=10000)
except Exception as exc: # noqa: BLE001
raise BrowserError("snapshot failed: %s" % exc)
truncated = len(text) > SNAPSHOT_LIMIT
if truncated:
text = text[:SNAPSHOT_LIMIT]
result = self._info()
result["text"] = text
result["truncated"] = truncated
return result
def click(self, selector):
if not selector or not str(selector).strip():
raise BrowserError("selector is required")
self._ensure()
try:
self._page.click(str(selector), timeout=10000)
self._current_url = self._page.url
except Exception as exc: # noqa: BLE001
raise BrowserError("click failed: %s" % exc)
result = self._info()
result["ok"] = True
return result
def fill(self, selector, text):
if not selector or not str(selector).strip():
raise BrowserError("selector is required")
self._ensure()
try:
self._page.fill(str(selector), "" if text is None else str(text),
timeout=10000)
except Exception as exc: # noqa: BLE001
raise BrowserError("fill failed: %s" % exc)
result = self._info()
result["ok"] = True
return result
def mouse_move(self, x, y):
try:
fx = float(x)
fy = float(y)
except (TypeError, ValueError):
raise BrowserError("mouse_move needs numeric x/y, got %r/%r"
% (x, y))
if not (0 <= fx <= 1280 and 0 <= fy <= 800):
raise BrowserError(
"mouse_move out of viewport 1280x800: %s,%s" % (x, y))
self._ensure()
try:
self._page.mouse.move(fx, fy)
except Exception as exc: # noqa: BLE001
raise BrowserError("mouse_move failed: %s" % exc)
result = self._info()
result["ok"] = True
result["x"] = fx
result["y"] = fy
return result
def key_press(self, key):
if not key or not str(key).strip():
raise BrowserError("key is required")
self._ensure()
try:
self._page.keyboard.press(str(key))
except Exception as exc: # noqa: BLE001
raise BrowserError("key_press failed: %s" % exc)
result = self._info()
result["ok"] = True
result["key"] = str(key)
return result
def type_text(self, text):
if text is None:
raise BrowserError("text is required")
self._ensure()
try:
self._page.keyboard.type(str(text))
except Exception as exc: # noqa: BLE001
raise BrowserError("type_text failed: %s" % exc)
result = self._info()
result["ok"] = True
return result
def snapshot_refs(self):
"""Accessibility-style snapshot with refs (playwright-mcp
style): interactive elements get a stable ref valid until
the next snapshot_refs call; click_ref(ref) clicks one.
The ref maps to a computed CSS path, so it survives
re-renders better than an index into a stale list."""
self._ensure()
script = """
() => {
const path = (el) => {
const parts = [];
while (el && el.nodeType === 1 && el !== document.body) {
let tag = el.tagName.toLowerCase();
const parent = el.parentElement;
if (parent) {
const sibs = Array.from(parent.children).filter(
c => c.tagName === el.tagName);
if (sibs.length > 1)
tag += ':nth-of-type(' + (sibs.indexOf(el) + 1) + ')';
}
parts.unshift(tag);
el = parent;
}
return parts.join(' > ');
};
const out = [];
const els = document.querySelectorAll(
'a, button, input, select, textarea, [role="button"], ' +
'[role="link"], [role="textbox"], [role="checkbox"], ' +
'[role="radio"], [role="combobox"]');
els.forEach((el) => {
const r = el.getBoundingClientRect();
if (r.width === 0 && r.height === 0) return;
const name = (el.getAttribute('aria-label') ||
el.textContent || el.value || el.placeholder || '')
.trim().replace(/\\s+/g, ' ').slice(0, 80);
out.push({tag: el.tagName.toLowerCase(),
role: el.getAttribute('role') || '',
name: name, path: path(el)});
});
return out;
}
"""
try:
elements = self._page.evaluate(script)
except Exception as exc: # noqa: BLE001
raise BrowserError("snapshot_refs failed: %s" % exc)
self._ref_paths = {}
items = []
for i, el in enumerate(elements or []):
ref = "e%d" % i
self._ref_paths[ref] = el.get("path", "")
items.append({"ref": ref, "tag": el.get("tag", ""),
"role": el.get("role", ""),
"name": el.get("name", "")})
result = self._info()
result["elements"] = items
result["count"] = len(items)
return result
def click_ref(self, ref):
if not ref or ref not in self._ref_paths:
raise BrowserError(
"unknown ref %r: run browser_snapshot_refs first" % (ref,))
self._ensure()
path = self._ref_paths[ref]
try:
self._page.locator(path).first.click(timeout=10000)
self._current_url = self._page.url
except Exception as exc: # noqa: BLE001
raise BrowserError("click_ref failed: %s" % exc)
result = self._info()
result["ok"] = True
result["ref"] = ref
return result
def set_frame_sink(self, sink):
"""Remote service: frames arrive here via CDP callback."""
self._frame_sink = sink
if self._page is not None:
self._start_screencast()
def _start_screencast(self):
if self._frame_sink is None or self._page is None:
return
if self._cdp is not None and self._cdp_page is self._page:
return
try:
cdp = self._page.context.new_cdp_session(self._page)
def _on_frame(params):
try:
self._frame_sink.put(
(params.get("sessionId", ""),
params.get("data", "")))
except Exception: # noqa: BLE001 - callback must not die
pass
cdp.on("Page.screencastFrame", _on_frame)
# everyNthFrame 1: full frame rate during motion.
# Static pages cost nothing extra (frames only arrive
# on repaint, and the bridge writes only changed
# bytes), so dropping the frame-skip buys
# responsiveness exactly when it matters -- scrolling,
# dragging, animation -- without a static-page tax.
cdp.send("Page.startScreencast",
{"format": "jpeg", "quality": 60,
"maxWidth": 1280, "maxHeight": 800,
"everyNthFrame": 1})
self._cdp = cdp
self._cdp_page = self._page
except Exception: # noqa: BLE001 - screencast is best-effort
self._cdp = None
self._cdp_page = None
def _eager_frame(self):
"""Push one current-viewport frame into the sink, best-effort.
Screencast frames only arrive on repaint, and the page may
already have painted before startScreencast ran -- so a
static page would otherwise show nothing until its next
repaint. Capturing the viewport once right after navigate
guarantees the bridge file (and any open stream) has a
picture within milliseconds of the page loading.
"""
if self._cdp is None or self._frame_sink is None:
return
try:
result = self._cdp.send(
"Page.captureScreenshot",
{"format": "jpeg", "quality": 60})
data = result.get("data") if isinstance(result, dict) \
else None
if data:
# Empty session id: pump stores it but must not ack
# it (there is no screencast frame to acknowledge).
self._frame_sink.put(("", data))
except Exception: # noqa: BLE001 - screencast still flows
pass
def pump_screencast(self):
"""Main-thread only: store the latest frame and ack every
real screencast frame (no ack = CDP stops sending after the
first). Eager frames carry no session id and skip ack.
Returns the latest frame data (base64 jpeg) or ''."""
if self._frame_sink is None:
return ""
latest = ""
while True:
try:
sid, data = self._frame_sink.get_nowait()
except Exception: # noqa: BLE001 - queue empty
break
if data:
latest = data
if self._cdp is not None and sid:
try:
self._cdp.send("Page.screencastFrameAck",
{"sessionId": sid})
except Exception: # noqa: BLE001 - ack best-effort
pass
if latest:
self._latest_frame = latest
return getattr(self, "_latest_frame", "")
def click_at(self, x, y):
"""Click by viewport coordinates (CSS pixels, origin at the
top-left of the 1280x800 viewport). This is the tool the
console live view drives: the user clicks on a screenshot
and the coordinates arrive here. Bounds-checked so a
mis-scaled click cannot scroll the page into nowhere."""
try:
fx = float(x)
fy = float(y)
except (TypeError, ValueError):
raise BrowserError("click_at needs numeric x/y, got %r/%r"
% (x, y))
if not (0 <= fx <= 1280 and 0 <= fy <= 800):
raise BrowserError(
"click_at out of viewport 1280x800: %s,%s" % (x, y))
self._ensure()
try:
self._page.mouse.click(fx, fy)
self._current_url = self._page.url
except Exception as exc: # noqa: BLE001
raise BrowserError("click_at failed: %s" % exc)
result = self._info()
result["ok"] = True
result["x"] = fx
result["y"] = fy
return result
def live_shot(self, output_filename=None):
"""Screenshot to a FIXED live-view file plus a JSON status
sidecar, so a watcher (console, user) can poll one stable
path instead of chasing per-shot filenames. The agent
should call this after every navigate/click/fill while a
live view is wanted. Returns path, bytes, url, title and
a unix timestamp."""
self._ensure()
name = _validate_basename(
output_filename or "browser-live.png", "output_filename")
path = os.path.join(self.cwd, name)
try:
self._page.screenshot(path=path)
except Exception as exc: # noqa: BLE001
raise BrowserError("live_shot failed: %s" % exc)
info = self._info()
status = {"image": name, "path": path,
"bytes": os.path.getsize(path),
"url": info["url"], "title": info["title"],
"timestamp": int(time.time())}
status_path = os.path.join(self.cwd, "browser-live.json")
with open(status_path, "w", encoding="utf-8") as fh:
json.dump(status, fh, ensure_ascii=False)
status["status_path"] = status_path
return status
def evaluate(self, expression):
if not expression or not str(expression).strip():
raise BrowserError("expression is required")
self._ensure()
try:
value = self._page.evaluate(str(expression))
except Exception as exc: # noqa: BLE001
raise BrowserError("evaluate failed: %s" % exc)
return {"result": str(value)[:4000]}
def screenshot(self, output_filename=None):
self._ensure()
name = _validate_basename(
output_filename or ("shot-%d.png" % int(time.time())),
"output_filename")
path = os.path.join(self.cwd, name)
try:
self._page.screenshot(path=path)
except Exception as exc: # noqa: BLE001
raise BrowserError("screenshot failed: %s" % exc)
return {"path": path, "filename": name,
"bytes": os.path.getsize(path)}
def close(self):
errors = []
if self._cdp is not None:
try:
self._cdp.send("Page.stopScreencast")
except Exception: # noqa: BLE001 - best-effort
pass
self._cdp = None
self._cdp_page = None
for closer in (lambda: self._page and self._page.close(),
lambda: self._browser and self._browser.close(),
lambda: self._pw and self._pw.stop()):
try:
closer()
except Exception as exc: # noqa: BLE001 - close is best-effort
errors.append(str(exc))
self._page = None
self._browser = None
self._pw = None
return {"closed": True, "errors": errors}
# ------------------------------------------------------- codex-home glue
def ensure_codex_home_playwright(codex_home_dir, command_args=None,
script_dir=None):
"""Seed playwright MCP files + config into a tenant codex-home.
MCP scripts are SYSTEM files, not tenant data: a tenant never
edits them (user files live in the worktree, not codex-home),
so unlike the old never-overwrite rule, a differing script is
REFRESHED to the deployed version and reported in
``script_refreshed``. Without this, every MCP feature ships
dead for existing projects: they keep the first-seeded script
forever and only brand-new projects get the update.
Appends ``[mcp_servers.playwright]`` only when absent. No
secrets live here -- proxy vars arrive via
``ensure_playwright_mcp_env`` from worker proxy_env, and the
browsers path is a fixed image path.
"""
import shutil
home = os.path.abspath(codex_home_dir)
os.makedirs(home, exist_ok=True)
here = os.path.abspath(script_dir or os.path.dirname(__file__))
script_changed = False
script_differs = []
script_refreshed = []
for name in ("playwright_browser.py", "playwright_mcp.py",
"playwright_remote.py"):
src = os.path.join(here, name)
dst = os.path.join(home, name)
if not os.path.exists(src):
continue
if not os.path.exists(dst):
shutil.copyfile(src, dst)
script_changed = True
else:
with open(src, "rb") as fh:
src_bytes = fh.read()
with open(dst, "rb") as fh:
dst_bytes = fh.read()
if src_bytes != dst_bytes:
shutil.copyfile(src, dst)
script_refreshed.append(name)
script_changed = True
continue
config_path = os.path.join(home, "config.toml")
if command_args is None:
command_args = ["python3",
os.path.join(home, "playwright_mcp.py")]
section = ("\n[mcp_servers.playwright]\n"
"command = %s\n"
"args = [%s]\n"
% (json.dumps(command_args[0]),
", ".join(json.dumps(a) for a in command_args[1:])))
config_changed = False
existing = ""
if os.path.exists(config_path):
with open(config_path, encoding="utf-8") as fh:
existing = fh.read()
if "[mcp_servers.playwright]" not in existing:
with open(config_path, "a", encoding="utf-8") as fh:
if existing and not existing.endswith("\n"):
fh.write("\n")
fh.write(section)
config_changed = True
return {"config_path": config_path,
"script_path": os.path.join(home, "playwright_mcp.py"),
"config_changed": config_changed,
"script_changed": script_changed,
"script_differs": script_differs,
"script_refreshed": script_refreshed}
def ensure_playwright_mcp_env(codex_home_dir, env):
"""Write [mcp_servers.playwright.env] into a tenant config.toml.
Same rationale as the websearch/imagegen env writers: Codex's
MCP subprocess does not inherit the Codex process env, so the
proxy vars and PLAYWRIGHT_BROWSERS_PATH must live in
config.toml. Idempotent in-place replacement of the env
subsection; other sections untouched. Returns True when the
file was written.
"""
if not env:
return False
home = os.path.abspath(codex_home_dir)
config_path = os.path.join(home, "config.toml")
try:
existing = ""
if os.path.exists(config_path):
with open(config_path, encoding="utf-8") as fh:
existing = fh.read()
except OSError:
return False
start = existing.find("[mcp_servers.playwright.env]")
if start >= 0:
end = existing.find("\n[", start + 1)
if end < 0:
end = len(existing)
existing = existing[:start] + existing[end:]
lines = ["\n[mcp_servers.playwright.env]\n"]
for key in sorted(env):
lines.append("%s = %s\n" % (key, json.dumps(str(env[key]))))
try:
with open(config_path, "w", encoding="utf-8") as fh:
fh.write(existing)
if existing and not existing.endswith("\n"):
fh.write("\n")
fh.writelines(lines)
except OSError:
return False
return True