Daoyuan Li d075be0277
fix(browserless): surface target-page error status in web_fetch_tool (#4239)
* fix(browserless): surface target-page error status in web_fetch_tool

Browserless returns HTTP 200 for the render request itself even when the
target page responded with a 4xx/5xx or served an anti-bot block page,
tagging the real outcome on X-Response-Code/X-Response-Status headers.
capture_screenshot/web_capture_tool already reads these headers and
surfaces a warning via _target_status_warning. fetch_html only logged
them at debug level and web_fetch_tool returned the block/error page's
raw text as if it were a normal successful fetch, with no indication
anything was wrong.

fetch_html now returns a BrowserlessFetchResult carrying the rendered
HTML plus the target-status headers (mirroring BrowserlessScreenshotResult),
and web_fetch_tool appends the same _target_status_warning used by
web_capture_tool when the target page errored. Legitimate 200-target
fetches are unaffected.

* fix(browserless): keep fetch_html() returning a plain string

BrowserlessClient is re-exported from deerflow.community.browserless.__all__,
so fetch_html() is public harness API with an established str-only contract:
the rendered HTML on success, or an "Error: ..." string on failure. Changing
its return type to BrowserlessFetchResult broke that contract for any caller
that treats the result as a string (.lower(), concatenation, passing to a
parser), even when the fetch itself succeeded.

fetch_html() is now a thin wrapper that always unwraps back to the original
str contract. The richer, status-aware result (needed to tell a genuine 200
apart from a render-succeeded-but-target-errored response) moves to a new
fetch_html_with_status() method, which web_fetch_tool now calls instead so it
keeps surfacing the target-page-error warning.

Tests: retarget the tool-level mocks onto fetch_html_with_status, add a direct
regression asserting fetch_html() returns str on success - including when the
target page itself errored under a 200 render response - and keep the
status-aware coverage on the new method.
2026-07-19 20:08:52 +08:00

271 lines
10 KiB
Python

import logging
from dataclasses import dataclass
from typing import Any
import httpx
logger = logging.getLogger(__name__)
@dataclass(frozen=True)
class BrowserlessFetchResult:
html: str
target_status_code: str
target_status: str
@dataclass(frozen=True)
class BrowserlessScreenshotResult:
content: bytes
content_type: str
target_status_code: str
target_status: str
final_url: str
def _get_header(headers: Any, name: str) -> str:
value = headers.get(name)
if value:
return str(value)
return str(headers.get(name.lower(), ""))
class BrowserlessClient:
"""Client for Browserless headless Chrome API."""
def __init__(self, base_url: str, token: str = "", timeout_s: float = 30) -> None:
self.base_url = base_url.rstrip("/")
self.token = token
self.timeout_s = timeout_s
async def fetch_html(
self,
url: str,
wait_for_event: str = "",
wait_for_timeout_ms: int = 0,
wait_for_selector: str = "",
wait_for_selector_timeout_ms: int = 5000,
reject_resource_types: list[str] | None = None,
reject_request_pattern: list[str] | None = None,
) -> str:
"""Fetch the rendered HTML of a page using Browserless.
Public string contract: this always returns either the rendered HTML or
an "Error: ..." string, never a richer result object. Callers that also
need the target page's real status (Browserless returns HTTP 200 for the
render request itself even when the target page responded with a 4xx/5xx
or an anti-bot block page) should use fetch_html_with_status() instead.
Args:
url: The URL to fetch.
wait_for_event: Wait for a page event (e.g. "networkidle", "load").
wait_for_timeout_ms: Extra wait after page load.
wait_for_selector: CSS selector to wait for.
wait_for_selector_timeout_ms: Timeout for selector wait.
reject_resource_types: Resource types to block (e.g. ["image"]).
reject_request_pattern: URL patterns to block.
Returns:
Rendered HTML content, or an "Error: ..." string on failure.
"""
result = await self.fetch_html_with_status(
url=url,
wait_for_event=wait_for_event,
wait_for_timeout_ms=wait_for_timeout_ms,
wait_for_selector=wait_for_selector,
wait_for_selector_timeout_ms=wait_for_selector_timeout_ms,
reject_resource_types=reject_resource_types,
reject_request_pattern=reject_request_pattern,
)
return result.html if isinstance(result, BrowserlessFetchResult) else result
async def fetch_html_with_status(
self,
url: str,
wait_for_event: str = "",
wait_for_timeout_ms: int = 0,
wait_for_selector: str = "",
wait_for_selector_timeout_ms: int = 5000,
reject_resource_types: list[str] | None = None,
reject_request_pattern: list[str] | None = None,
) -> BrowserlessFetchResult | str:
"""Fetch the rendered HTML of a page using Browserless, with target status.
Same request/response handling as fetch_html(), except a successful fetch
returns a BrowserlessFetchResult carrying the target page's real status
headers instead of a bare string, so a caller can tell a genuine 200 apart
from a render-succeeded-but-target-errored (or anti-bot blocked) response.
Use fetch_html() instead when only the HTML/error string is needed.
Only sends accepted parameters for the current Browserless API version.
Sets a default navigation timeout (30s) via query param.
Args:
url: The URL to fetch.
wait_for_event: Wait for a page event (e.g. "networkidle", "load").
wait_for_timeout_ms: Extra wait after page load.
wait_for_selector: CSS selector to wait for.
wait_for_selector_timeout_ms: Timeout for selector wait.
reject_resource_types: Resource types to block (e.g. ["image"]).
reject_request_pattern: URL patterns to block.
Returns:
Fetch result with the rendered HTML and target-page status headers,
or an "Error: ..." string on failure.
"""
payload: dict[str, Any] = {
"url": url,
}
if self.token:
payload["token"] = self.token
if wait_for_event:
payload["waitForEvent"] = wait_for_event
if wait_for_timeout_ms > 0:
payload["waitForTimeout"] = wait_for_timeout_ms
if wait_for_selector:
payload["waitForSelector"] = {
"selector": wait_for_selector,
"timeout": wait_for_selector_timeout_ms,
}
if reject_resource_types:
payload["rejectResourceTypes"] = reject_resource_types
if reject_request_pattern:
payload["rejectRequestPattern"] = reject_request_pattern
logger.debug(f"Fetching URL via Browserless: {url}")
try:
async with httpx.AsyncClient(timeout=self.timeout_s) as client:
resp = await client.post(
f"{self.base_url}/content",
json=payload,
headers={
"Content-Type": "application/json",
"Cache-Control": "no-cache",
},
)
code = resp.status_code
target_code = resp.headers.get("X-Response-Code", "")
target_status = resp.headers.get("X-Response-Status", "")
logger.debug(f"Browserless response: code={code}, target_code={target_code}, target_status={target_status}")
if code != 200:
return f"Error: Browserless HTTP {code}: {resp.text[:200]}"
html = resp.text
if not html or not html.strip():
return "Error: Browserless returned empty response"
return BrowserlessFetchResult(
html=html,
target_status_code=_get_header(resp.headers, "X-Response-Code"),
target_status=_get_header(resp.headers, "X-Response-Status"),
)
except httpx.TimeoutException:
return f"Error: Browserless request timed out after {self.timeout_s}s"
except httpx.RequestError as e:
logger.error(f"Browserless request failed: {e}")
return f"Error: Browserless request failed: {e!s}"
except Exception as e:
logger.error(f"Browserless fetch failed: {e}")
return f"Error: Browserless fetch failed: {e!s}"
async def capture_screenshot(
self,
url: str,
full_page: bool = True,
output_format: str = "png",
quality: int | None = None,
viewport: dict[str, int] | None = None,
wait_for_selector: str = "",
wait_for_selector_timeout_ms: int = 5000,
wait_for_timeout_ms: int = 0,
best_attempt: bool = False,
) -> BrowserlessScreenshotResult | str:
"""Capture a rendered screenshot of a URL using Browserless.
Args:
url: URL to render.
full_page: Capture the full page instead of just the viewport.
output_format: Image format: png, jpeg, or webp.
quality: Optional quality for jpeg/webp outputs.
viewport: Optional browser viewport dictionary.
wait_for_selector: CSS selector to wait for before capture.
wait_for_selector_timeout_ms: Timeout for selector wait.
wait_for_timeout_ms: Extra wait after navigation.
best_attempt: Continue when waits time out.
Returns:
Screenshot result with binary content, or an error string.
"""
payload: dict[str, Any] = {
"url": url,
"options": {
"fullPage": full_page,
"type": output_format,
},
}
if quality is not None:
payload["options"]["quality"] = quality
if viewport:
payload["viewport"] = viewport
if wait_for_selector:
payload["waitForSelector"] = {
"selector": wait_for_selector,
"timeout": wait_for_selector_timeout_ms,
}
if wait_for_timeout_ms > 0:
payload["waitForTimeout"] = wait_for_timeout_ms
if best_attempt:
payload["bestAttempt"] = True
params = {"token": self.token} if self.token else None
logger.debug(f"Capturing URL screenshot via Browserless: {url}")
try:
async with httpx.AsyncClient(timeout=self.timeout_s) as client:
resp = await client.post(
f"{self.base_url}/screenshot",
json=payload,
params=params,
headers={
"Content-Type": "application/json",
"Cache-Control": "no-cache",
},
)
code = resp.status_code
logger.debug(
"Browserless screenshot response: code=%s, target_code=%s, target_status=%s",
code,
resp.headers.get("X-Response-Code", ""),
resp.headers.get("X-Response-Status", ""),
)
if code != 200:
return f"Error: Browserless HTTP {code}: {resp.text[:200]}"
content = resp.content
if not content:
return "Error: Browserless returned empty screenshot response"
return BrowserlessScreenshotResult(
content=content,
content_type=_get_header(resp.headers, "Content-Type"),
target_status_code=_get_header(resp.headers, "X-Response-Code"),
target_status=_get_header(resp.headers, "X-Response-Status"),
final_url=_get_header(resp.headers, "X-Response-URL"),
)
except httpx.TimeoutException:
return f"Error: Browserless screenshot request timed out after {self.timeout_s}s"
except httpx.RequestError as e:
logger.error(f"Browserless screenshot request failed: {e}")
return f"Error: Browserless screenshot request failed: {e!s}"
except Exception as e:
logger.error(f"Browserless screenshot failed: {e}")
return f"Error: Browserless screenshot failed: {e!s}"