feat(ai): ecosysteme d'outils phase 2 - recherche a cle, cache/retry, Playwright, crawl, Gitea/GitHub, documents (#92)

backend/tools/webrender.py

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+"""Dynamic page rendering (Playwright) — ``fetch_url(render=True)``.
+
+Static pages are fetched with httpx inside :mod:`backend.tools.web`. Dynamic
+pages (SPA/React, JS-loaded content) need a real browser engine; this module
+runs one Playwright call inside a dedicated worker thread so browser
+crashes/timeouts never take over the tool layer, and the heavyweight
+dependency stays optional:
+
+* not installed → ``ToolError(code="playwright_unavailable")`` with a clear
+  message (the assistant explains the limitation instead of hanging);
+* installed → ``pip install playwright && playwright install chromium``.
+
+The SSRF guard (scheme + private-address rejection) is applied before the
+browser navigates. Note: unlike the httpx path, internal redirects performed
+by the browser engine are not re-checked hop by hop.
+"""
+
+from __future__ import annotations
+
+import html as html_lib
+import logging
+import re
+from concurrent.futures import ThreadPoolExecutor
+from typing import Any
+
+from backend.tools.context import ToolError
+from backend.tools.web import (
+    MAX_TEXT_CHARS,
+    USER_AGENT,
+    _assert_public_http_url,
+    _html_to_text,
+)
+
+logger = logging.getLogger("obsigate.tools.webrender")
+
+# One worker: browser automation is serialized on purpose (one Chromium at a
+# time keeps memory predictable on small hosts).
+_executor = ThreadPoolExecutor(max_workers=1, thread_name_prefix="obsigate-playwright")
+GOTO_TIMEOUT_MS = 20_000
+
+
+def _playwright_available() -> bool:
+    try:
+        import playwright  # noqa: F401
+    except ImportError:
+        return False
+    return True
+
+
+def _render_in_worker(url: str) -> dict[str, Any]:
+    """Synchronous Playwright render — runs in the dedicated worker thread."""
+    from playwright.sync_api import sync_playwright
+
+    status = 0
+    with sync_playwright() as p:
+        browser = p.chromium.launch(headless=True)
+        try:
+            page = browser.new_page(user_agent=USER_AGENT)
+            response = page.goto(url, wait_until="networkidle", timeout=GOTO_TIMEOUT_MS)
+            if response is not None:
+                status = response.status
+            raw = page.content()
+            title = html_lib.unescape(page.title() or "").strip()
+            text = _html_to_text(raw)[:MAX_TEXT_CHARS]
+        finally:
+            browser.close()
+    title = re.sub(r"\s+", " ", title)[:300]
+    return {
+        "url": url,
+        "status": status,
+        "title": title,
+        "text": text,
+        "rendered": True,
+        "truncated": len(raw) > MAX_TEXT_CHARS,
+    }
+
+
+def render_page(url: str) -> dict[str, Any]:
+    """Render *url* (JavaScript included) and return readable text.
+
+    Raises:
+        ToolError: ``playwright_unavailable`` when the optional dependency is
+            missing, ``render_unavailable`` when the render itself failed.
+    """
+    _assert_public_http_url(url)
+    if not _playwright_available():
+        raise ToolError(
+            "Rendu dynamique indisponible : Playwright n'est pas installé "
+            "(pip install playwright && playwright install chromium).",
+            code="playwright_unavailable",
+        )
+    try:
+        return _executor.submit(_render_in_worker, url).result(timeout=GOTO_TIMEOUT_MS / 1000 + 40)
+    except ToolError:
+        raise
+    except Exception as e:
+        logger.warning("render_page failed for %s: %s", url, e)
+        raise ToolError(
+            "Le rendu dynamique de la page a échoué.", code="render_unavailable"
+        ) from e