16d4399c28
deployment_timestamp was int(time.time()) per-request, giving every page load a new ?v=... query string on custom.css. Cloudflare treats each unique URL as a new resource, so the CSS was fetched from the VM on every page load — 64 KB over the wire per navigation. Token now tied to static/css/custom.css mtime. The URL only changes when the CSS actually changes, so Cloudflare can hold the file for its full 4h TTL. Degraded-mode fallback preserves today's behaviour if the file isn't on disk. 3 new CacheBustTokenTests; all 68 tests pass. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
45 lines
1.8 KiB
Python
45 lines
1.8 KiB
Python
# === core/context_processors.py ===
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# Globals injected into every template render.
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#
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# `deployment_timestamp` is a cache-bust token on our CSS URL. Historically
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# it was `int(time.time())` — a new value every second — which defeated
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# Cloudflare's edge cache because every page load saw a different `?v=...`
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# string. We now tie the token to `custom.css`'s mtime, so the URL
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# changes ONLY when the CSS actually changes. Cloudflare can hold the
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# file for its full 4h TTL, and users on repeat visits hit the browser
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# cache (304 Not Modified).
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import os
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import time
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from pathlib import Path
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from django.conf import settings
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# Path to the file whose mtime drives the cache-bust token. Module-level
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# constant so tests can monkey-patch it to simulate "file missing".
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_CSS_PATH_FOR_TOKEN = Path(settings.BASE_DIR) / 'static' / 'css' / 'custom.css'
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def _compute_cache_bust_token():
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"""Return an integer cache-bust token.
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Normal path: returns the CSS file's mtime (an integer).
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Fallback: if the file can't be stat'd (doesn't exist / permission
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error / disk issue), returns the current wall-clock time in seconds
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— that degrades to the PRE-FIX behaviour (new token per request)
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rather than crashing the whole request cycle.
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"""
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try:
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return int(os.path.getmtime(_CSS_PATH_FOR_TOKEN))
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except (OSError, FileNotFoundError):
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return int(time.time())
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def project_context(request):
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"""Adds project-specific environment variables to the template context globally."""
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return {
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"project_description": os.getenv("PROJECT_DESCRIPTION", ""),
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"project_image_url": os.getenv("PROJECT_IMAGE_URL", ""),
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# Cache-busts static assets — see _compute_cache_bust_token().
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"deployment_timestamp": _compute_cache_bust_token(),
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}
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