Cache.coffee

Cache.coffee is a library written for data caching. Like HTML5's appcache, it saves data at first request, and when request again it returns the data cached and update in the background. As for backend, it uses localStorage (or jStorage unless localStorage is available)

Data Request ->
    if Cache in RAM
        Return Data
    else
        if Cache in Storage
            Return Data
            Update In the background
        else
            if Already In Request Queue
                Wait until event fires
            else
                Fetch Data

Requement

• underscore.js

License

Licensed under The MIT License.

Copyright (C) 2013 Zeno Zeng

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.

Document

Cache.get()

• id

  [String] Cache ID

• fetch

  [Function] function to fetch data

  Example:

  fetch = function(success, error) {
      $.ajax({
          url: 'http://example.com/abc.json',
          success: success,
          error: error
      });
  }

• parse

  [Function] function to parse data fetched

  Default:

  parse = function(data) {
      return data;
  }

• validate

  [Function] function to validate data parsed

  Default:

  validate = function(data) {
      return true;
  }

• update

  [Function] function returning true or false, update data if true

  Example:

  update = function() {
      if((new Date()).getTime() - lastUpdate > 1000) {
          return true;
      } else {
          return false;
      }
  }
  

• updateAfter

  [Function] accepts an arg for callback

  Example:

  updateAfter = function(callback) {
      $(document).ready(function() {
          callback();
      });
  }
  

• success

  [Function] function to handle data when success

  Example:

  success = function(data) {
      console.log(data);
  }

• error

  [Function] function to handle error

  Example:

  error = function(e) {
      console.log(e);
  }

Cache.timestamp()

var cache, microtime;
cache = new Cache({prefix: "myprefix_"});
microtime = cache.timestamp('cacheID');

Examples (in Javascirpt)

Basic Usage:

var cache, fetch, success;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success) {
    $.get('http://example.com/abc.json', success);
}
success = function(data) {
    // do sth with data;
}
cache.get({id: 'cacheID', fetch: fetch, success: success})

Error Handle

var cache, fetch, success, error;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success, error) {
    $.ajax({
        url: 'http://example.com/abc.json',
        success: success,
        error: error
    });
}
success = function(data) {
    // do sth with data;
}
error = function(e) {
    console.error(e);
}
cache.get({id: 'cacheID', fetch: fetch, success: success, error: error})

Data Parse

var cache, fetch, parse, success, error;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success, error) {
    $.ajax({
        url: 'http://example.com/api/data',
        success: success,
        error: error
    });
}
success = function(data) {
    // do sth with data;
}
error = function(e) {
    console.error(e);
}
parse = function(data) {
    return JSON.parse(data);
}
cache.get({id: 'cacheID', fetch: fetch, parse: parse, success: success, error: error})

Data Validation

var cache, fetch, validate, success, error;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success, error) {
    $.ajax({
        url: 'http://example.com/api/data',
        success: success,
        error: error
    });
}
success = function(data) {
    // do sth with data;
}
error = function(e) {
    console.error(e);
}
validate = function(data) {
    if(data.length > 100) {
        return true;
    } else {
        return false;
    }
}
cache.get({id: 'cacheID', fetch: fetch, validate: validate, success: success, error: error})

Update Control

Example 1

var cache, fetch, success;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success) {
    $.get('http://example.com/abc.json', success);
}
success = function(data) {
    // do sth with data;
}
cache.get({id: 'cacheID', fetch: fetch, update: false, success: success})

Example 2

var cache, fetch, update, success;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success) {
    $.get('http://example.com/abc.json', success);
}
success = function(data) {
    // do sth with data;
}
update = function() {
    if(some condition here) {
        return true;
    } else {
        return false;
    }
}
cache.get({id: 'cacheID', fetch: fetch, update: update, success: success})

Update with Delay

var cache, fetch, updateAfter, success;
cache = new Cache({prefix: "myprefix_"})
fetch = function(success) {
    $.get('http://example.com/abc.json', success);
}
success = function(data) {
    // do sth with data;
}
updateAfter = function(callback) {
    $(document).ready(function() {
        callback();
    });
}
cache.get({id: 'cacheID', fetch: fetch, updateAfter: updateAfter, success: success})

Get Cache Timestamp

var cache, microtime;
cache = new Cache({prefix: "myprefix_"});
microtime = cache.timestamp('cacheID');

Turn On Debug

cache = new Cache({prefix: "myprefix_", debug: true});
// some code here