node-cache

Simple and fast NodeJS internal caching.

A simple caching module that has set, get and delete methods and works a little bit like memcached. Keys can have a timeout after which they expire and are cleaned from the cache.
All keys are stored in a single object so the practical limit is at around 1m keys.

Written in coffee-script

Install

  npm install node-cache

Or just require the node_cache.js file to get the superclass

Examples:

Initialize (INIT):

var NodeCache = require( "node-cache" );
var myCache = new NodeCache();

Options

stdTTL: the standard ttl as number in seconds for every generated cache element. Default = 0 = unlimited
checkperiod: The period in seconds, as a number, used for the automatic delete check interval. 0 = no periodic check

var NodeCache = require( "node-cache" );
var myCache = new NodeCache( { stdTTL: 100, checkperiod: 120 } );

Store a key (SET):

myCache.set( key, val, [ ttl ], callback )

Sets a key value pair. It is possible to define a ttl (in seconds).
Returns true on success.

obj = { my: "Special", variable: 42 };
myCache.set( "myKey", obj, function( err, success ){
  if( !err && success ){
    console.log( success );
    // true
    // ... do something ...
  }
});

Retrieve a key (GET):

myCache.get( key, callback )

Gets a saved value from the cache. Returns an empty object {} if not found or expired. If the value was found it returns an object with the key value pair.

myCache.get( "myKey", function( err, value ){
  if( !err ){
    console.log( value );
    // { "myKey": { my: "Special", variable: 42 } }
    // ... do something ...
  }
});

Get multiple keys (MGET):

myCache.get( [ key1, key2, ... ,keyn ], callback )

Gets multiple saved values from the cache. Returns an empty object {} if not found or expired. If the value was found it returns an object with the key value pair.

myCache.get( [ "myKeyA", "myKeyB" ], function( err, value ){
  if( !err ){
    console.log( value );
    /*
      {
        "myKeyA": { my: "Special", variable: 123 },
        "myKeyB": { the: "Glory", answer: 42 }
      }
    */
    // ... do something ...
  }
});

Delete a key (DEL):

myCache.del( key, callback )

Delete a key. Returns the number of deleted entries. A delete will never fail.

myCache.del( "myKey", function( err, count ){
  if( !err ){
    console.log( count ); // 1
    // ... do something ...
  }
});

Delete multiple keys (MDEL):

myCache.del( [ key1, key2, ... ,keyn ], callback )

Delete multiple keys. Returns the number of deleted entries. A delete will never fail.

myCache.del( [ "myKeyA", "myKeyB" ], function( err, count ){
  if( !err ){
    console.log( count ); // 2
    // ... do something ...
  }
});

Change TTL (TTL):

myCache.ttl( key, ttl, callback )

Redefine the ttl of a key. Returns true if the key has been found and changed. Otherwise returns false.
If the ttl-argument isn't passed the default-TTL will be used.

myCache = new NodeCache( { stdTTL: 100 } )
myCache.ttl( "existendKey", 100, function( err, changed ){
  if( !err ){
    console.log( changed ); // true
    // ... do something ...
  }
});

myCache.ttl( "missingKey", 100, function( err, changed ){
  if( !err ){
    console.log( changed ); // false
    // ... do something ...
  }
});

myCache.ttl( "existendKey", function( err, changed ){
  if( !err ){
    console.log( changed ); // true
    // ... do something ...
  }
});

Statistics (STATS):

myCache.getStats()

Returns the statistics.

myCache.getStats();
  /*
    {
      keys: 0,    // global key count
      hits: 0,    // global hit count
      misses: 0,  // global miss count
      ksize: 0,   // global key size count
      vsize: 0    // global value size count
    }
  */

Flush all data (FLUSH):

myCache.flushAll()

Flush all data.

myCache.flushAll();
myCache.getStats();
  /*
    {
      keys: 0,    // global key count
      hits: 0,    // global hit count
      misses: 0,  // global miss count
      ksize: 0,   // global key size count
      vsize: 0    // global value size count
    }
  */

Events

set

Fired when a key has been added or changed. You will get the key and the value as callback argument.

myCache.on( "set", function( key, value ){
	// ... do something ...  
});

del

Fired when a key has been removed manually or due to expiry. You will get the key as callback argument.

myCache.on( "del", function( key ){
	// ... do something ...  
});

expired

Fired when a key expires. You will get the key as callback argument.

myCache.on( "expired", function( key ){
	// ... do something ...  
});

flush

Fired when the cache has been flushed.

myCache.on( "flush", function(){
	// ... do something ...  
});

Release History

Version	Date	Description
v0.4.0	2013-10-02	Added nodecache events
v0.3.2	2012-05-31	Added Travis tests

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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