feat: add cache TTL configuration and implement cache eviction logic

config.yml

@@ -4,6 +4,10 @@ PORT: 8008
 CACHE_DIR: ./local-cache
 LOG_REQUESTS: false
 
+# Delete cached artifacts that haven't been re-downloaded in this many days.
+# Comment out (or remove) to keep cached artifacts forever.
+# CACHE_TTL_DAYS: 365
+
 IGNORE_FILES:
   - react-native-0.61.5.pom
   - -sources.jar

src/config.ts

@@ -21,6 +21,8 @@ const CACHE_DIR = path.resolve(config.CACHE_DIR, '__MMT_CACHE__');
 const TMP_DIR = path.resolve(config.CACHE_DIR, '__MMT_TMP__');
 const DEFAULT_PATH = config.DEFAULT_PATH ?? 'v1';
 const VERBOSE = config.LOG_REQUESTS ?? false;
+// Unset (undefined) means cached artifacts are kept forever, matching prior behavior.
+const CACHE_TTL_DAYS = config.CACHE_TTL_DAYS;
 
 export {
   PORT,
@@ -31,5 +33,6 @@ export {
   DEFAULT_PATH,
   IGNORE_FILES,
   REPOSITORIES,
+  CACHE_TTL_DAYS,
   VALID_FILE_TYPES,
 };

src/downloader/got.ts

@@ -7,6 +7,7 @@ import { PROXIES, CACHE_DIR, TMP_DIR, REPOSITORIES } from '../config';
 import { ProxyAgent } from 'proxy-agent';
 import { TServer } from 'app/types';
 import { extractFileInfo } from '../utils';
+import { logger } from '../logger';
 
 interface DownloadEntry {
   responses: Set<Response>;
@@ -172,7 +173,7 @@ export class GotDownloader {
         addToResponses();
       }
 
-      console.log(`🔗 [${srv.name}]`, url);
+      logger.info(`🔗 [${srv.name}] ${url}`);
       return;
     }
 
@@ -210,13 +211,13 @@ export class GotDownloader {
 
     stream.once('downloadProgress', ({ total }) => {
       if (total) {
-        console.log(`⏳ [${srv.name}]`, url);
+        logger.info(`⏳ [${srv.name}] ${url}`);
       }
     });
 
     stream.on('error', (err) => {
-      console.log('❌', srv.url + url);
-      console.log('⛔️', err.message);
+      logger.error(`❌ ${srv.url + url}`);
+      logger.error(`⛔️ ${err.message}`);
       // Destroy all waiting responses
       for (const res of entry.responses) {
         if (!res.destroyed) {
@@ -258,7 +259,7 @@ export class GotDownloader {
           gotResponse.statusCode >= 200 &&
           gotResponse.statusCode < 300
         ) {
-          console.log(`✅ [${srv.name}]`, url);
+          logger.info(`✅ [${srv.name}] ${url}`);
           const destPath = path.join(
             CACHE_DIR,
             srv.name,

src/handlers/cache-handler.ts

@@ -3,7 +3,8 @@ import { RequestHandler } from 'express';
 
 import { GotDownloader } from '../downloader/got';
 import { CACHE_DIR } from '../config';
-import { getCachedServer } from '../utils';
+import { getCachedServer, touchFile } from '../utils';
+import { logger } from '../logger';
 
 const downloader = new GotDownloader();
 
@@ -13,7 +14,8 @@ export const CacheRequestHandler: RequestHandler = (request, response) => {
   const server = getCachedServer(url);
   if (server) {
     const cachedPath = path.join(CACHE_DIR, server.name, url);
-    console.log(`📦 [${server.name}]`, url);
+    logger.info(`📦 [${server.name}] ${url}`);
+    touchFile(cachedPath);
     return response.sendFile(cachedPath);
   }
 

src/handlers/gradle-plugins-handler.ts

@@ -1,6 +1,7 @@
 import { RequestHandler } from 'express';
 import got from 'got';
 import { extractFileInfo, getCachedServer } from '../utils';
+import { logger } from '../logger';
 
 const gradleApi = 'https://plugins.gradle.org/api/gradle/4.10/plugin/use';
 
@@ -40,7 +41,7 @@ export const LegacyGradlePluginsHandler: RequestHandler = (req, res, next) => {
           url.replaceAll(`${info.id}.gradle.plugin`, newId)
         )?.[0];
         const newUrl = `${basePath}/${/^[\w.]+(?=:)/.exec(info.implementation.gav)?.[0]?.replaceAll('.', '/')}/${newId}/${version}/${newFileName}`;
-        console.log('🔀 [301]', url);
+        logger.info(`🔀 [301] ${url}`);
         req.headers['alias-url'] = url.replace(/^\/\w+\//, '/');
         req.url = newUrl;
         next();
@@ -49,8 +50,7 @@ export const LegacyGradlePluginsHandler: RequestHandler = (req, res, next) => {
         next();
       });
   } catch (error) {
-    // eslint-disable-next-line @typescript-eslint/no-unused-expressions
-    error;
+    logger.warn(`⚠️  failed to resolve legacy gradle plugin ${url}`, error);
     next();
   }
 };

src/handlers/validate-request-handler.ts

@@ -2,6 +2,7 @@ import { RequestHandler } from 'express';
 
 import { IGNORE_FILES, VALID_FILE_TYPES } from '../config';
 import { extractFileInfo } from '../utils';
+import { logger } from '../logger';
 
 export const ValidateRequestHandler: RequestHandler = (req, res, next) => {
   const url = req.url.replace(/^\/\w+\//, '/');
@@ -12,16 +13,16 @@ export const ValidateRequestHandler: RequestHandler = (req, res, next) => {
   const { fileExtension } = extractFileInfo(url);
 
   if (!VALID_FILE_TYPES.includes('.' + fileExtension)) {
-    console.log('♻️', url);
+    logger.info(`♻️  [404] ${url}`);
     return res.status(404);
   }
 
   if (IGNORE_FILES.find((str) => url.includes(str))) {
-    console.log('❌ [404]', url);
+    logger.info(`❌ [404] ${url}`);
     return res.status(404);
   }
 
-  console.log(req.method, url);
+  logger.info(`${req.method} ${url}`);
 
   next();
 };

src/index.ts

@@ -4,8 +4,15 @@ import chalk from 'chalk';
 import morgan from 'morgan';
 import express from 'express';
 
-import { PORT, TMP_DIR, VERBOSE, CACHE_DIR, DEFAULT_PATH } from './config';
-import { printServedEndpoints } from './utils';
+import {
+  PORT,
+  TMP_DIR,
+  VERBOSE,
+  CACHE_DIR,
+  DEFAULT_PATH,
+  CACHE_TTL_DAYS,
+} from './config';
+import { printServedEndpoints, evictExpiredCacheFiles } from './utils';
 
 import { CacheRequestHandler } from './handlers/cache-handler';
 import { ValidateRequestHandler } from './handlers/validate-request-handler';
@@ -21,6 +28,16 @@ if (!fs.existsSync(path.resolve(TMP_DIR))) {
   fs.mkdirSync(path.resolve(TMP_DIR), { recursive: true });
 }
 
+// evict stale cache entries on startup, then on a recurring sweep
+if (CACHE_TTL_DAYS) {
+  const CACHE_SWEEP_INTERVAL_MS = 24 * 60 * 60 * 1000;
+  evictExpiredCacheFiles(CACHE_DIR, CACHE_TTL_DAYS);
+  setInterval(
+    () => evictExpiredCacheFiles(CACHE_DIR, CACHE_TTL_DAYS!),
+    CACHE_SWEEP_INTERVAL_MS
+  );
+}
+
 const app = express();
 if (VERBOSE) {
   app.use(morgan('combined'));

src/logger.ts

@@ -0,0 +1,35 @@
+enum Level {
+  Warn = 'w',
+  Info = 'i',
+  Error = 'e',
+}
+
+const pad = (n: number, width = 2) => String(n).padStart(width, '0');
+
+// Local wall-clock time with its UTC offset, e.g. 2026/07/01 14:32:05.123
+const formatLocalTimestamp = (date: Date) => {
+  return (
+    `${date.getFullYear()}/${pad(date.getMonth() + 1)}/${pad(date.getDate())} ` +
+    `${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}.${pad(date.getMilliseconds(), 3)}`
+  );
+};
+
+const write = (level: Level, message: string, ...args: unknown[]) => {
+  const line = `${formatLocalTimestamp(new Date())} [${level.toUpperCase()}] ${message}`;
+  if (level === Level.Error) {
+    console.error(line, ...args);
+  } else if (level === Level.Warn) {
+    console.warn(line, ...args);
+  } else {
+    console.log(line, ...args);
+  }
+};
+
+export const logger = {
+  info: (message: string, ...args: unknown[]) =>
+    write(Level.Info, message, ...args),
+  warn: (message: string, ...args: unknown[]) =>
+    write(Level.Warn, message, ...args),
+  error: (message: string, ...args: unknown[]) =>
+    write(Level.Error, message, ...args),
+};

src/utils.ts

@@ -3,6 +3,7 @@ import os from 'os';
 import path from 'path';
 
 import { CACHE_DIR, REPOSITORIES } from './config';
+import { logger } from './logger';
 
 export const getCachedServer = (filePath: string) => {
   const srv = REPOSITORIES.find((s) => {
@@ -52,29 +53,69 @@ export const printServedEndpoints = (
   }
 };
 
-export const extractFileInfo = (url: string) => {
-  // Split the pathname into segments
-  const segments = url.split('/');
+// Eviction only cares about day-level age, so skip the metadata write
+// when the file was already touched recently in this window.
+const TOUCH_THRESHOLD_MS = 24 * 60 * 60 * 1000;
 
-  // Get the last segment (filename)
-  const filename = segments[segments.length - 1].replace(/\?.*$/, '');
+// Bump mtime so eviction tracks last-served time, not last-downloaded time
+// (sendFile() never touches the file, so a frequently-served cache hit would
+// otherwise look just as stale as one nobody has asked for in months).
+export const touchFile = (filePath: string) => {
+  try {
+    const { mtimeMs } = fs.statSync(filePath);
+    if (Date.now() - mtimeMs < TOUCH_THRESHOLD_MS) {
+      return;
+    }
+    const now = new Date();
+    fs.utimesSync(filePath, now, now);
+  } catch {
+    // best-effort; a missed touch just makes the file evict a bit early
+  }
+};
 
-  // Extract the file extension
-  const fileExtension = filename.split('.').pop();
+export const evictExpiredCacheFiles = (
+  cacheDir: string,
+  ttlDays: number
+): void => {
+  const maxAgeMs = ttlDays * 24 * 60 * 60 * 1000;
+  const cutoff = Date.now() - maxAgeMs;
+  let removed = 0;
 
-  // Construct the relative path (excluding the filename)
-  const relativePath = segments.slice(0, -1).join('/');
+  const walk = (dir: string) => {
+    let entries: fs.Dirent[];
+    try {
+      entries = fs.readdirSync(dir, { withFileTypes: true });
+    } catch {
+      return;
+    }
 
-  // Create the output object
-  const fileInfo = {
-    fileName: filename,
-    relativePath: relativePath,
-    fileExtension: fileExtension,
-  } as {
-    fileName: string;
-    relativePath: string;
-    fileExtension: string;
+    for (const entry of entries) {
+      const entryPath = path.join(dir, entry.name);
+      if (entry.isDirectory()) {
+        walk(entryPath);
+        continue;
+      }
+      const { mtimeMs } = fs.statSync(entryPath);
+      if (mtimeMs < cutoff) {
+        fs.unlinkSync(entryPath);
+        removed += 1;
+      }
+    }
   };
 
-  return fileInfo;
+  walk(cacheDir);
+  if (removed > 0) {
+    logger.info(`🧹 evicted ${removed} cached file(s) older than ${ttlDays}d`);
+  }
+};
+
+export const extractFileInfo = (url: string) => {
+  // Use a dummy base so relative/absolute paths both parse, then strip the query string
+  const pathname = new URL(url, 'http://localhost').pathname;
+
+  const fileName = path.basename(pathname);
+  const relativePath = path.dirname(pathname);
+  const fileExtension = path.extname(fileName).replace(/^\./, '');
+
+  return { fileName, relativePath, fileExtension };
 };

types.d.ts

@@ -27,5 +27,6 @@ export interface IConfig {
   LOG_REQUESTS?: boolean;
   IGNORE_FILES?: string[];
   VALID_FILE_TYPES?: string[];
+  CACHE_TTL_DAYS?: number;
   PROXIES: Record<string, TProxy>;
 }