63 lines
1.9 KiB
TypeScript
63 lines
1.9 KiB
TypeScript
import { Psql } from "@core/db/psql";
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import { SlidingWindow } from "@core/mq/slidingWindow.ts";
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import { redis } from "@core/db/redis.ts";
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import { getIdentifier } from "@/middleware/rateLimiters.ts";
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import { Context } from "hono";
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type seconds = number;
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export interface CaptchaDifficultyConfig {
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global: boolean;
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duration: seconds;
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threshold: number;
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difficulty: number;
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}
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export const getCaptchaDifficultyConfigByRoute = async (sql: Psql, route: string): Promise<CaptchaDifficultyConfig[]> => {
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return sql<CaptchaDifficultyConfig[]>`
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SELECT duration, threshold, difficulty, global
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FROM captcha_difficulty_settings
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WHERE CONCAT(method, '-', path) = ${route}
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ORDER BY duration
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`;
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};
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export const getCaptchaConfigMaxDuration = async (sql: Psql, route: string): Promise<seconds> => {
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const rows = await sql<{max: number}[]>`
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SELECT MAX(duration)
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FROM captcha_difficulty_settings
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WHERE CONCAT(method, '-', path) = ${route}
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`;
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if (rows.length < 1){
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return Number.MAX_SAFE_INTEGER;
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}
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return rows[0].max;
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}
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export const getCurrentCaptchaDifficulty = async (sql: Psql, c: Context | string): Promise<number | null> => {
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const isRoute = typeof c === "string";
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const route = isRoute ? c : `${c.req.method}-${c.req.path}`
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const configs = await getCaptchaDifficultyConfigByRoute(sql, route);
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if (configs.length < 1) {
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return null
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}
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else if (configs.length == 1) {
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return configs[0].difficulty
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}
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const maxDuration = configs.reduce((max, config) =>
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Math.max(max, config.duration), 0);
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const slidingWindow = new SlidingWindow(redis, maxDuration);
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for (let i = 1; i < configs.length; i++) {
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const config = configs[i];
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const lastConfig = configs[i - 1];
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const identifier = isRoute ? c : getIdentifier(c, config.global);
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const count = await slidingWindow.count(`captcha-${identifier}`, config.duration);
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if (count >= config.threshold) {
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continue;
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}
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return lastConfig.difficulty
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}
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return configs[configs.length-1].difficulty;
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}
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