varcache

A pure memory based cache for Node.js

Installation

npm install varcache

Usage

var cache = require('varcache');

// Storing an item in the cache.
cache.set('test', 'Something quite awesome!');

// Getting an item from the cache.
var test = cache.get('test');

// Deleting an item from the cache.
cache.delete('test');

// Storing an item in the cache with expiration and callbacks.
cache.set(
	'test',
	'Semething even more awesome...',
	5000,
	function (key, data) {
		console.log('Just stored "' + key + '" with:');
		console.log(data);
	},
	function (key) {
		console.log('"' + key + '" just expired.');
	}
);

This should print this:

Something quite awesome!
Just stored "test" with:
Semething even more awesome...

... 5 seconds later ...

"test" just expired.

Available functions

• clear
• debug
• delete
• get
• hitCount
• hitLog
• keys
• keysCount
• missCount
• missLog
• recordHits
• recordMisses
• set

Functions

clear

Clears the entire cache hold of entries.

Available parameters:

• callback (function)

Simple call:

cache.clear();

Can be extended to trigger a callback after the items are cleared.

cache.clear(function () {
	console.log('Cache is not cleared.');
});

debug

Enables, or disables, debug mode, which logs evething it does to the console.

Available parameters:

• value (boolean)

Simple call:

cache.debug();

Can be extended to specify the boolean value to turn it on or off.

cache.debug(false);

delete

Deletes an entry by-key or several items if an array of keys are passed.

Available parameters:

• key/keys (string/array)
• callback (function)

Simple call:

cache.delete('test-key-1');

Or with an array of keys:

cache.delete([ 'test-key-2', 'test-key-3' ]);

Can be extended to trigger a callback for each key which is deleted.

cache.delete('test-key-1', function (key) {
	console.log('Just deleted key: "' + key + '".');
});

get

Gets the stored value for the given key in the cache.

Available parameters:

• key (string)
• callbackHit (function)
• callbackMiss (function)

Simple call:

var value = cache.get('key');

Can be extended to trigger callbacks for both hit and miss.

var value = cache.get(
	'key',
	function (key, data) {
		console.log('Found key: "' + key + '" with value:');
		console.log(data);
	},
	function (key) {
		console.log('No data cached for key: "' + key + '".');
	}
);

hitCount

Returns the number of key-hits recorded, which is how many times data has been requested from the cache. This requires that the recordHist() function has been called.

Available parameters:

• callback (function)

Simple call:

var count = cache.hitCount();

Can be extended to trigger a callback with the number.

cache.hitCount(function (count) {
	console.log('Total hits for keys are: ' + count.toString());
});

hitLog

Returns the log of hits, which returns the entire log for every hit against the cache. This requires that the recordHist() function has been called.

Available parameters:

• callback (function)

Simple call:

var hits = cache.hitLog();

Can be extended to trigger a callback with the log.

cache.hitLog(function (hits) {
	console.log(hits);
});

keys

Returns all stored keys, which is convenient for management

Available parameters:

• callback (function)

Simple call:

var keys = cache.keys();

Can be extended to trigger a callback with the keys.

cache.keys(function (keys) {
	console.log(keys);
});

keysCount

Returns the number of keys stored.

Available parameters:

• callback (function)

Simple call:

var count = cache.keysCount();

Can be extended to trigger a callback with the number.

cache.keysCount(function (count) {
	console.log(count);
});

missCount

Returns the number of key-misses recorded, which is how many times data has been requested without existing in the cache. This requires that the recordMisses() function has been called.

Available parameters:

• callback (function)

Simple call:

var count = cache.missCount();

Can be extended to trigger a callback with the number.

cache.missCount(function (count) {
	console.log('Total misses for keys are: ' + count.toString());
});

missLog

Returns the log of misses, which returns the entire log for every miss against the cache. This requires that the recordMisses() function has been called.

Available parameters:

• callback (function)

Simple call:

var misses = cache.missLog();

Can be extended to trigger a callback with the log.

cache.missLog(function (misses) {
	console.log(misses);
});

recordHits

Enables, or disables, recording of hits in the cache. Default for this is set to false.

Available parameters:

• value (boolean)

Simple call:

cache.recordHits();

Can be extended to specify the boolean value to turn it on or off.

cache.recordHits(false);

recordMisses

Enables, or disables, recording of misses in the cache. Default for this is set to false.

Available parameters:

• value (boolean)

Simple call:

cache.recordMisses();

Can be extended to specify the boolean value to turn it on or off.

cache.recordMisses(false);

set

Creates, or updates, an item in the cache with all the fixins.

Available parameters:

• key (string)
• data (any)
• ttl (int)
• callbackSet (function)
• callbackExpires (function)

Simple call:

cache.set('key', 'value');

This stores the "value" by the "key" forever. Can be extended to include how many milliseconds the value is to be stored in the cache.

cache.set('key', 'value', 5000);

This will store the data for 5 seconds. If you set 0, the data is stored without an expiration. Can also be extended to trigger callbacks when the data is set and when the data expires.

cache.set(
	'key',
	'value',
	5000,
	function (record) {
		console.log('This is the newly created record, which contains some metadata:');
		console.log(record);
	},
	function (key) {
		console.log('The entry with key: "' + key + '" just expired.');
	}
);