29 lines
901 B
TypeScript
29 lines
901 B
TypeScript
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/**
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* Prepared-statement cache. better-sqlite3 does not cache `db.prepare`, so
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* re-preparing the same SQL on every call re-parses it. This memoizes prepared
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* statements per connection (WeakMap), which matters for hot paths such as
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* authentication and the reverse proxy.
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* @module dshs/db/prepared
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*/
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import type Database from 'better-sqlite3'
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import type { Database as Db } from './connection.js'
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type Statement = Database.Statement<unknown[], unknown>
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const caches = new WeakMap<Db, Map<string, Statement>>()
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/** Prepare (and cache) a statement for a connection. */
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export function prepare(db: Db, sql: string): Statement {
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let cache = caches.get(db)
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if (cache === undefined) {
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cache = new Map()
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caches.set(db, cache)
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}
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let statement = cache.get(sql)
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if (statement === undefined) {
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statement = db.prepare(sql)
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cache.set(sql, statement)
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}
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return statement
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}
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