FileCache: allow custom getCacheKey

src/FileCache.ts

@@ -17,20 +17,14 @@ function jsonParse(data: string, cb: (err: Error | null, result?: any) => void):
   cb(null, result);
 }
 
-function getCacheKey(url: string): string {
-  const hash = createHash('sha512')
-  hash.update(url)
-  return hash.digest('hex')
-}
-
 export default class FileCache implements ICache {
   private readonly _location: string;
   constructor(location: string) {
     this._location = location;
   }
 
   getResponse(url: string, callback: (err: null | Error, response: null | CachedResponse) => void) {
-    const key = resolve(this._location, getCacheKey(url));
+    const key = resolve(this._location, this.getCacheKey(url));
 
     fs.readFile(key + '.json', 'utf8', function (err, data) {
       if (err && err.code === 'ENOENT') return callback(null, null);
@@ -47,7 +41,7 @@ export default class FileCache implements ICache {
   }
 
   setResponse(url: string, response: CachedResponse): void {
-    const key = resolve(this._location, getCacheKey(url));
+    const key = resolve(this._location, this.getCacheKey(url));
     let errored = false;
 
     fs.mkdir(this._location, function (err) {
@@ -76,7 +70,7 @@ export default class FileCache implements ICache {
   }
 
   updateResponseHeaders(url: string, response: Pick<CachedResponse, 'headers' | 'requestTimestamp'>) {
-    const key = resolve(this._location, getCacheKey(url));
+    const key = resolve(this._location, this.getCacheKey(url));
     fs.readFile(key + '.json', 'utf8', function (err, data) {
       if (err) {
         console.warn('Error writing to cache: ' + err.message);
@@ -103,10 +97,16 @@ export default class FileCache implements ICache {
   }
 
   invalidateResponse(url: string, callback: (err: NodeJS.ErrnoException | null) => void): void {
-    const key = resolve(this._location, getCacheKey(url));
+    const key = resolve(this._location, this.getCacheKey(url));
     fs.unlink(key + '.json', (err?: NodeJS.ErrnoException | null) => {
       if (err && err.code === 'ENOENT') return callback(null);
       else callback(err || null);
     });  
   }
+
+  getCacheKey(url: string): string {
+    const hash = createHash('sha512');
+    hash.update(url);
+    return hash.digest('hex');
+  }
 }

test/cache.js

@@ -2,14 +2,16 @@
 
 var assert = require('assert');
 var request = require('../');
+var FileCache = require('../lib/FileCache').default;
 var http = require('http');
 var serveStatic = require('serve-static');
 var rimraf = require('rimraf');
 var path = require('path');
 var url = require('url');
 var qs = require('querystring');
 
-rimraf.sync(path.resolve(__dirname, '..', 'lib', 'cache'));
+const cacheDir = path.resolve(__dirname, '..', 'lib', 'cache');
+rimraf.sync(cacheDir);
 
 
 var CACHED_BY_CACHE_CONTROL = 'http://localhost:3293/index.js';
@@ -297,6 +299,32 @@ lastModifiedServer.listen(5295, function onListen() {
       }, 1000);
     });
   });
+
+  const staticKeyCache = new FileCache(cacheDir);
+  staticKeyCache.getCacheKey = function (res) {
+    return 'static-key';
+  };
+  request('GET', CACHED_BY_CACHE_CONTROL, {cache: staticKeyCache}, function (err, res) {
+    if (err) throw err;
+
+    console.log('response O (populate file cache)');
+    assert(res.statusCode === 200);
+    assert(res.fromCache === undefined);
+    assert(res.fromNotModified === undefined);
+    res.body.on('data', function () {});
+    res.body.on('end', function () {
+      setTimeout(function () {
+        request('GET', CACHED_BY_CACHE_CONTROL + '?a=b', {cache: staticKeyCache}, function (err, res) {
+          if (err) throw err;
+
+          console.log('response P (from file cache)');
+          assert(res.statusCode === 200);
+          assert(res.fromCache === true);
+          res.body.resume();
+        });
+      }, 1000);
+    });
+  });
 });
 
 lastModifiedServer.unref();