chant

A key-value styles cached layer framework.

Install

$ npm install chant

Example

var chant = require("chant");

var memory  = {};
var storage = {};

// create front layer (cache)
var front = chant.create({
    get: function (key, callback) {
        callback(null, memory[key]);
    },

    put: function (key, value, callback) {
        memory[key] = value;
        callback();
    },

    delete: function (key, callback) {
        delete memory[key];
        callback();
    },

    clean: function (callback) {
        memory = {};
        callback();
    },
});

// create back layer (main storage)
var back = chant.create({
    get: function (key, callback) {
        callback(null, storage[key]);
    },

    put: function (key, value, callback) {
        storage[key] = value;
        callback();
    },

    delete: function (key, callback) {
        delete storage[key];
        callback();
    },

    clean: function (callback) {
        callback();  // do nothing.
    },
});


var data = chant.chain(front, back);

data.put("name", "chant", function () {
  //...
});

data.get("name", function (err, value) {
  //...
});

Methods

var cache = chant.create(action)

Create chant cached layer instance.

action parameters (all required):

• action.get = function (key, callback) { ... } - action for get a value of key.
• action.put = function (key, value, callback) { ... } - action for put a value of key.
• action.delete = function (key, callback) { ... } - action for delete a value of key.
• action.clean = function (callback) { ... } - action for clean up cache.

cache.get(key, callback)

Get a value of key from cache. It will call action.get().

cache.put(key, value, callback)

Put a value of key to cache. It will call action.put().

cache.delete(key, value, callback)

Delete a value of key from cache. It will call action.delete().

cache.clean(callback)

Clean up a cache. It will call action.clean().

var chain = chant.chain(front_cache, back_cache)

Create chant chained cache.

chain.get(key, callback)

Get a value of key from chained cache.

It will call front_cache.get() first, return value and finish if front layer cache has a value, or call back_cache.get() next, return value and call front_cache.put() with key, value.

chain.put(key, value, callback)

Put a value of key to chained cache.

It will call front_cache.put() and back_cache.put() with key, value.

chain.delete(key, value, callback)

Delete a value of key from chained cache.

It will call front_cache.delete() and back_cache.delete() with key.

chain.clean(callback)

Clean up a chained cache. It will call action.clean().

It will call front_cache.clean() and back_cache.clean() with key.

License

Licensed under the MIT License.

Copyright (c) 2014 Yosuke Kumakura

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.