feat: Allow to change how cache is stored

README.md

@@ -49,6 +49,8 @@ module.exports = {
 |:--:|:--:|:-----:|:----------|
 |**`cacheDirectory`**|`{String}`|`path.resolve('.cache-loader')`|Provide a cache directory where cache items should be stored|
 |**`cacheIdentifier`**|`{String}`|`cache-loader:{version} {process.env.NODE_ENV}`|Provide an invalidation identifier which is used to generate the hashes. You can use it for extra dependencies of loaders.|
+|**`writeCache`**|`{Function(cacheFilename, content, callback) -> {void}}`|`undefined`|Allows you to override default write cache data to file (e.g. Redis, memcached).|
+|**`readCache`**|`{Function(cacheFilename, callback) -> {void}}`|`undefined`|Allows you to override default read cache data from file.|
 
 <h2 align="center">Examples</h2>
 

src/index.js

@@ -9,7 +9,17 @@ const pkgVersion = require('../package.json').version;
 const defaultCacheDirectory = path.resolve('.cache-loader');
 const ENV = process.env.NODE_ENV || 'development';
 
+const defaultOptions = {
+  cacheDirectory: defaultCacheDirectory,
+  cacheIdentifier: `cache-loader:${pkgVersion} ${ENV}`,
+  readCache,
+  writeCache,
+};
+
 function loader(...args) {
+  const loaderOptions = loaderUtils.getOptions(this) || {};
+  const options = Object.assign({}, defaultOptions, loaderOptions);
+  const { writeCache: writeCacheFn } = options;
   const callback = this.async();
   const { data } = this;
   const dependencies = this.getDependencies().concat(this.loaders.map(l => l.path));
@@ -36,13 +46,13 @@ function loader(...args) {
     }
     const [deps, contextDeps] = taskResults;
     const writeCacheFile = () => {
-      fs.writeFile(data.cacheFile, JSON.stringify({
+      writeCacheFn(data.cacheFile, JSON.stringify({
         remainingRequest: data.remainingRequest,
         cacheIdentifier: data.cacheIdentifier,
         dependencies: deps,
         contextDependencies: contextDeps,
         result: args,
-      }), 'utf-8', () => {
+      }), () => {
         // ignore errors here
         callback(null, ...args);
       });
@@ -64,20 +74,16 @@ function loader(...args) {
 
 function pitch(remainingRequest, prevRequest, dataInput) {
   const loaderOptions = loaderUtils.getOptions(this) || {};
-  const defaultOptions = {
-    cacheDirectory: defaultCacheDirectory,
-    cacheIdentifier: `cache-loader:${pkgVersion} ${ENV}`,
-  };
   const options = Object.assign({}, defaultOptions, loaderOptions);
-  const { cacheIdentifier, cacheDirectory } = options;
+  const { cacheIdentifier, cacheDirectory, readCache: readCacheFn } = options;
   const data = dataInput;
   const callback = this.async();
   const hash = digest(`${cacheIdentifier}\n${remainingRequest}`);
   const cacheFile = path.join(cacheDirectory, `${hash}.json`);
   data.remainingRequest = remainingRequest;
   data.cacheIdentifier = cacheIdentifier;
   data.cacheFile = cacheFile;
-  fs.readFile(cacheFile, 'utf-8', (readFileErr, content) => {
+  readCacheFn(cacheFile, (readFileErr, content) => {
     if (readFileErr) {
       callback();
       return;
@@ -123,4 +129,12 @@ function digest(str) {
   return crypto.createHash('md5').update(str).digest('hex');
 }
 
+function writeCache(cacheFile, content, callback) {
+  fs.writeFile(cacheFile, content, 'utf-8', callback);
+}
+
+function readCache(cacheFile, callback) {
+  fs.readFile(cacheFile, 'utf-8', callback);
+}
+
 export { loader as default, pitch };