Ryth Azhur
e5f8fafc01
Mizan's protocol layers (origin Redis cache, Edge Worker) handle caching
autonomously. The origin emits Cache-Control: no-store on ALL responses —
browsers and non-Mizan intermediaries must not cache. The Edge Worker
controls CDN caching via cf object, independent of origin headers.
Also fixes:
- TS localeCompare → byte-order sort (localeCompare is locale-sensitive,
would produce different HMAC keys for non-ASCII params vs Python)
- Python cache_purge: empty {} params no longer treated as falsy
(was inconsistent with JS where {} is truthy)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
58 lines
1.8 KiB
TypeScript
58 lines
1.8 KiB
TypeScript
/**
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* Cache key derivation — HMAC-SHA256 over JSON-canonical form.
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*
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* Protocol-critical: must produce identical output to Python's derive_cache_key.
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* Cross-language conformance verified by pin tests.
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*
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* Key format: "ctx:{context}:{hmac_hex}" — enables broad purge by prefix scan.
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*/
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import { createHmac } from 'crypto'
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const CONTEXT_KEY_PREFIX = 'ctx:'
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/**
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* JSON.stringify with recursively sorted keys and no whitespace.
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* Equivalent to Python's json.dumps(obj, sort_keys=True, separators=(",", ":"))
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*/
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function stableStringify(obj: any): string {
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if (obj === null || obj === undefined) return 'null'
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if (typeof obj === 'string') return JSON.stringify(obj)
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if (typeof obj === 'number' || typeof obj === 'boolean') return String(obj)
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if (Array.isArray(obj)) {
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return '[' + obj.map(stableStringify).join(',') + ']'
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}
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const keys = Object.keys(obj).sort()
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const pairs = keys.map(k => JSON.stringify(k) + ':' + stableStringify(obj[k]))
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return '{' + pairs.join(',') + '}'
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}
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/**
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* Derive a deterministic HMAC-SHA256 cache key.
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*
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* Returns "ctx:{context}:{hmac_hex}".
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*/
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export function deriveCacheKey(
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secret: string,
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context: string,
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params: Record<string, any>,
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userId?: string,
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rev: number = 0,
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): string {
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const sortedParams: Record<string, string> = {}
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for (const [k, v] of Object.entries(params).sort(([a], [b]) => a < b ? -1 : a > b ? 1 : 0)) {
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sortedParams[k] = String(v)
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}
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const keyData: Record<string, any> = { c: context, p: sortedParams, r: rev }
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if (userId !== undefined) {
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keyData.u = String(userId)
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}
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const message = stableStringify(keyData)
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const hmacHex = createHmac('sha256', secret).update(message).digest('hex')
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return `${CONTEXT_KEY_PREFIX}${context}:${hmacHex}`
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}
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export { CONTEXT_KEY_PREFIX }
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