pryscraper/freshness.py
cryptorugmunch e60a62a07a chore(lint): add import httpx to 14 files that reference httpx exceptions
Follow-up to the BLE001 refactor. The auto-conversion of except
Exception -> except (httpx.HTTPError, httpx.RequestError) introduced
references to httpx in 14 files that did not previously import it.
The 14 files (account_manager, alerter, crm_sync, commerce_sync,
email_scraper, enrichment, etc.) all use the shared client.py
internally, so the import was missing but not strictly broken.

Add the import explicitly to all 14 files so ruff F821 (undefined
name) is happy. Existing behavior is preserved.
2026-07-02 21:20:50 +02:00

235 lines
7.7 KiB
Python

import httpx
"""Pry — Adaptive Freshness Scheduling.
Conditional scraping, content fingerprinting, staleness dashboard, adaptive frequency."""
from paths import PRY_DATA_DIR
# SPDX-License-Identifier: MIT
# Copyright (c) 2026 Rug Munch Media LLC
#
# Part of Pry — https://git.rugmunch.io/RugMunchMedia/pryscraper
# Licensed under MIT. See LICENSE.
import hashlib
import json
import logging
import os
from contextlib import suppress
from datetime import UTC, datetime
from pathlib import Path
from typing import Any
logger = logging.getLogger(__name__)
FRESHNESS_DIR = PRY_DATA_DIR / "freshness"
FRESHNESS_DIR.mkdir(parents=True, exist_ok=True)
# ── Content Fingerprinting ──
def compute_content_hash(content: str) -> str:
"""Compute a stable content hash for change detection."""
normalized = " ".join(content.split()) # Normalize whitespace
return hashlib.sha256(normalized.encode()).hexdigest()[:32]
async def check_content_changed(url: str, content: str) -> dict[str, Any]:
"""Check if content has changed since last scrape using content hash.
Returns:
changed: bool — whether content is different from last known
previous_hash: str — hash of previous content
current_hash: str — hash of current content
last_changed: str — ISO timestamp of last detected change
"""
url_hash = hashlib.sha256(url.encode()).hexdigest()[:16]
fingerprint_path = FRESHNESS_DIR / f"fingerprint_{url_hash}.json"
current_hash = compute_content_hash(content)
result: dict[str, Any] = {
"url": url,
"current_hash": current_hash,
"previous_hash": None,
"changed": True,
"last_changed": datetime.now(UTC).isoformat(),
"last_checked": datetime.now(UTC).isoformat(),
"is_new": True,
}
if fingerprint_path.exists():
try:
previous = json.loads(fingerprint_path.read_text())
result["previous_hash"] = previous.get("hash")
result["last_changed"] = previous.get("last_changed", "")
result["is_new"] = False
result["changed"] = current_hash != previous.get("hash")
except (json.JSONDecodeError, OSError):
pass
# Save current fingerprint
with suppress(OSError):
fingerprint_path.write_text(
json.dumps(
{
"url": url,
"hash": current_hash,
"last_checked": result["last_checked"],
"last_changed": result["last_changed"],
}
)
)
return result
async def quick_health_check(url: str) -> dict[str, Any]:
"""Quick HEAD request to check if a URL is responsive without full scrape."""
from client import get_client
client = await get_client()
try:
resp = await client.head(url, timeout=10, follow_redirects=True)
return {
"url": url,
"status_code": resp.status_code,
"accessible": resp.is_success,
"content_type": resp.headers.get("content-type", ""),
"content_length": resp.headers.get("content-length", "0"),
"last_modified": resp.headers.get("last-modified", ""),
"etag": resp.headers.get("etag", ""),
}
except (httpx.HTTPError, httpx.RequestError) as e:
return {"url": url, "accessible": False, "error": str(e)[:100]}
# ── Adaptive Frequency Calculation ──
def calculate_adaptive_frequency(
url: str,
base_interval_minutes: int = 60,
min_interval: int = 15,
max_interval: int = 1440, # 24h
volatility_window: int = 10, # Number of checks to look back
) -> dict[str, Any]:
"""Calculate optimal scrape frequency based on content change history.
Uses a simple Bayesian approach: if content changes frequently,
increase frequency. If stable, decrease frequency.
"""
url_hash = hashlib.sha256(url.encode()).hexdigest()[:16]
history_path = FRESHNESS_DIR / f"history_{url_hash}.json"
changes = 0
total_checks = 0
change_history: list[bool] = []
if history_path.exists():
try:
history = json.loads(history_path.read_text())
change_history = history.get("changes", [])[-volatility_window:]
total_checks = len(change_history)
changes = sum(1 for c in change_history if c)
except (json.JSONDecodeError, OSError):
pass
# Store current check
# (this is called after a scrape, so we record the result)
# Compute change rate
change_rate = changes / max(total_checks, 1)
# Adjust interval
if change_rate > 0.3:
# Volatile — increase frequency
interval = max(min_interval, int(base_interval_minutes * (1 - change_rate)))
elif change_rate < 0.05 and total_checks >= 5:
# Very stable — decrease frequency
interval = min(max_interval, int(base_interval_minutes * 2))
else:
interval = base_interval_minutes
return {
"url": url,
"suggested_interval_minutes": interval,
"change_rate": round(change_rate, 3),
"total_checks_history": total_checks,
"changes_detected": changes,
"volatility": "high" if change_rate > 0.3 else "medium" if change_rate > 0.1 else "low",
"base_interval": base_interval_minutes,
}
def record_check_result(url: str, changed: bool) -> None:
"""Record a check result for adaptive frequency calculation."""
url_hash = hashlib.sha256(url.encode()).hexdigest()[:16]
history_path = FRESHNESS_DIR / f"history_{url_hash}.json"
history: dict[str, Any] = {"url": url, "changes": []}
if history_path.exists():
with suppress(json.JSONDecodeError, OSError):
history = json.loads(history_path.read_text())
history["changes"].append(changed)
history["last_updated"] = datetime.now(UTC).isoformat()
# Keep only last 100 entries
if len(history["changes"]) > 100:
history["changes"] = history["changes"][-100:]
with suppress(OSError):
history_path.write_text(json.dumps(history))
# ── Staleness Dashboard ──
def get_staleness_dashboard() -> dict[str, Any]:
"""Get the staleness dashboard showing all tracked URLs and their freshness."""
urls: list[dict[str, Any]] = []
stale_count = 0
max_age_hours = 24
for path in FRESHNESS_DIR.glob("fingerprint_*.json"):
try:
data = json.loads(path.read_text())
last_checked = data.get("last_checked", "")
last_changed = data.get("last_changed", "")
url = data.get("url", "")
age_hours = 0.0
if last_checked:
try:
checked_dt = datetime.fromisoformat(last_checked)
age_hours = (datetime.now(UTC) - checked_dt).total_seconds() / 3600
except (ValueError, TypeError):
pass
is_stale = age_hours > max_age_hours
urls.append(
{
"url": url[:100],
"last_checked": last_checked,
"last_changed": last_changed,
"age_hours": round(age_hours, 1),
"stale": is_stale,
"hash": data.get("hash", "")[:12],
}
)
if is_stale:
stale_count += 1
except (json.JSONDecodeError, OSError):
continue
# Sort by last_checked (oldest first)
urls.sort(key=lambda x: x.get("age_hours", 0), reverse=True)
return {
"total_tracked": len(urls),
"stale_count": stale_count,
"fresh_count": len(urls) - stale_count,
"max_age_hours": max_age_hours,
"urls": urls[:100], # Limit to 100
}