filestream-cache - npm Package Compare versions

Comparing version 0.0.2 to 1.0.0

index.js

@@ -8,2 +8,3 @@ var fs = require('fs');
 var mkdirp = require('mkdirp');
+var twelveHoursInSeconds = 43200;
 
@@ -16,4 +17,7 @@ /**
  */
-function StreamCache(rootDirectory) {
+function StreamCache(rootDirectory, options) {
 	this.rootCacheDirectory = rootDirectory;
+	options = options || {};
+	this.defaultTtl = options.defaultTtl || twelveHoursInSeconds;
+	this.serveStale = options.serveStale || false;
 
@@ -33,2 +37,31 @@ // TODO: Where's best to handle errors here?
 
+StreamCache.prototype.getMetaData = function(identifier) {
+	var cachedObjectPath = this._getCachedObjectPath(identifier);
+	var cache = this;
+
+	return this._getReadFileDescriptor(identifier).then(function(fd) {
+		return cache._getMetaDataUsingFileDescriptor(fd);
+	});
+};
+
+StreamCache.prototype._getMetaDataUsingFileDescriptor = function(fd) {
+	return new Promise(function(resolve, reject) {
+		fs.fstat(fd, function(err, stat) {
+			if (err) {
+				reject(err);
+				return;
+			}
+
+			var lastModified = (stat.mtime.getTime() / 1000)|0;
+			var timeNowInSeconds = ((Date.now() / 1000)|0);
+
+			resolve({
+				age: timeNowInSeconds - lastModified,
+				firstCreated: (stat.birthtime.getTime() / 1000)|0,
+				lastModified: lastModified
+			});
+		});
+	});
+};
+
 /**
@@ -52,6 +85,15 @@ * Get a Stream from the cache, if the stream doesn't exist, create it via the
 	cache._read(identifier, options).then(function(stream) {
-		if (stream) {
+		if (!stream) {
+			var newStream;
+
+			try {
+				newStream = createCallback();
+			} catch(err) {
+				passThroughStream.emit('error', err);
+				throw err;
+			}
+
+			cache.writeThrough(identifier, newStream).pipe(passThroughStream);
+		} else {
 			stream.pipe(passThroughStream);
-		} else {
-			cache.writeThrough(identifier, createCallback()).pipe(passThroughStream);
 		}
@@ -123,27 +165,48 @@ });
 StreamCache.prototype._read = function(identifier, options) {
-	options = options || {};
 	var cachedObjectPath = this._getCachedObjectPath(identifier);
+	var cache = this;
 
-	var newerThan = options.newerThan || 0;
+	return this._getReadFileDescriptor(identifier).then(function(fd) {
+		return cache._isStale(fd).then(function(isStale) {
+			if (isStale) {
+				return false;
+			} else {
+				// First argument of fs.createReadStream is ignored
+				// because the 'fd' is present
+				return fs.createReadStream(false, { fd: fd, autoClose: true });
+			}
+		});
 
+
+	}).catch(function(e) {
+		return false;
+	});
+};
+
+StreamCache.prototype.isStale = function(identifier) {
+	var cache = this;
+	return this._getReadFileDescriptor(identifier).then(function(fd) {
+		return cache._isStale(fd);
+	});
+};
+
+StreamCache.prototype._isStale = function(fd) {
+	var defaultTtl = this.defaultTtl;
+
+	return this._getMetaDataUsingFileDescriptor(fd).then(function(metadata) {
+		return metadata.age > defaultTtl;
+	});
+};
+
+StreamCache.prototype._getReadFileDescriptor = function(identifier, options) {
+	var cachedObjectPath = this._getCachedObjectPath(identifier);
+
 	return new Promise(function(resolve, reject) {
 		fs.open(cachedObjectPath, 'r', function(e, fd) {
 			if (e) {
-				resolve(false);
-			} else {
-				fs.fstat(fd, function(e, stats) {
-					if (stats.mtime < newerThan) {
-						resolve(false);
-					} else {
-						// First argument of fs.createReadStream is ignored
-						// because the 'fd' is present
-						var readStream = fs.createReadStream(false, { fd: fd });
-						readStream.on('end', function() {
-							// Close fd
-							fs.close(fd);
-						});
-						resolve(readStream);
-					}
-				});
+				reject(e);
+				return;
 			}
+
+			resolve(fd);
 		});
@@ -150,0 +213,0 @@ });

package.json

@@ -17,4 +17,4 @@ {
   },
-  "version": "0.0.2",
+  "version": "1.0.0",
   "license": "MIT"
 }

test/test.js

@@ -1,3 +0,2 @@
-var StreamCache = require('../index');
-var fs = require('fs');
+var StreamCache = require('../index'); var fs = require('fs');
 var assert = require('assert');
@@ -9,2 +8,13 @@ var helpers = require('./testhelper');
 
+	describe("#isStale(identifier)", function() {
+		it("should return true, if the cache object is stale", function(done) {
+			helpers.testIsStale(-1, true, done);
+		});
+
+		it("should return false, if the cache object is not stale", function(done) {
+			helpers.testIsStale(4000, false, done);
+		});
+
+	});
+
 	describe("#purge(callback)", function() {
@@ -62,2 +72,45 @@ it("should purge any objects from the cache where the Promise returned from the callback resolves as true", function(done) {
 	describe("#get(identifier, options, callback)", function() {
+
+		it("should, if the cached object's age is older than the default ttl, create a new stream and overwrite the cache", function(done) {
+			var streamContent = 'my test stream content';
+			var testBucket = 'get#test-create-stale';
+			var cacheKey = 'testkey';
+
+			var testDirectory = helpers.localTestDirectory(testBucket);
+			var streamCache = new StreamCache(testDirectory, { defaultTtl: -1 });
+
+			var streamCreateCount = 0;
+
+			var cachedStream = streamCache.get(cacheKey, {}, function() {
+				streamCreateCount++;
+				return helpers.createStream(streamContent + " - first create").end();
+			});
+
+			cachedStream.on('data', function() { /* do nothing */ });
+			cachedStream.on('error', function(e) { rmrf(testDirectory); done(e); });
+			cachedStream.on('end', function()  { next(); });
+
+			function next() {
+				var content = streamContent + " - second create";
+				var freshStream = streamCache.get(cacheKey, {}, function() {
+					streamCreateCount++;
+					return helpers.createStream(content).end();
+				});
+
+				var bufferedContent = "";
+
+				freshStream.on('data', function(data) {
+					bufferedContent += data.toString();
+				});
+				freshStream.on('error', function(e) { rmrf(testDirectory); done(e); });
+
+				freshStream.on('end', function() {
+					rmrf(testDirectory);
+					assert.equal(streamCreateCount, 2);
+					assert.equal(bufferedContent, content);
+					done();
+				});
+			}
+		});
+
 		it("should, if the cache key does not exist, create a new stream using the callback and cache it", function(done) {
@@ -64,0 +117,0 @@ var streamContent = 'my test stream content';

test/testhelper.js

@@ -8,2 +8,3 @@ 'use strict';
 var StreamCache = require('../index');
+var assert = require('assert');
 
@@ -63,2 +64,38 @@ function localTestDirectory(bucket) {
 
+function testIsStale(defaultTtl, isExpectedStale, done) {
+
+	var streamContent = 'my test stream content';
+	var testBucket = "isStale#true";
+	var testDirectory = localTestDirectory(testBucket);
+	var cacheKey = 'cachekey';
+
+	var streamCache = new StreamCache(testDirectory, { defaultTtl: defaultTtl });
+
+	var cachedStream = streamCache.get(cacheKey, {}, function() {
+		return createStream(streamContent).end();
+	});
+
+	cachedStream.on('error', function(e) {
+		rmrf(testDirectory);
+		done(e);
+	});
+
+	var bufferedData = '';
+
+	cachedStream.on('data', function(data) {
+		bufferedData += data.toString();
+	});
+
+	cachedStream.on('end', function() {
+		streamCache.isStale(cacheKey).then(function(isStale) {
+			assert.equal(isExpectedStale, isStale);
+			rmrf(testDirectory);
+			done();
+		}).catch(function(e) {
+			rmrf(testDirectory);
+			done(e);
+		});
+	});
+}
+
 module.exports = {
@@ -68,3 +105,4 @@ localTestDirectory: localTestDirectory,
 	testPurgeFunction: testPurgeFunction,
+	testIsStale: testIsStale,
 	createStream: createStream
 };

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Improved metrics

Total package byte prevSize

18780

increased by27.24%

Lines of code

452

increased by34.12%

Number of low quality alerts

1

decreased by-50%

Number of low supply chain risk alerts

4

decreased by-20%

Worsened metrics

Number of package files

7

decreased by-12.5%

No dependency changes