1 /*

     2 Copyright (c) 2009, Yahoo! Inc. All rights reserved.

     3 Code licensed under the BSD License:

     4 http://developer.yahoo.net/yui/license.txt

     5 version: 3.0.0

     6 build: 1549

     7 */

     8 YUI.add('datasource-cache', function(Y) {

     9 

    10 /**

    11  * Extends DataSource with caching functionality.

    12  *

    13  * @module datasource

    14  * @submodule datasource-cache

    15  */

    16 

    17 /**

    18  * Adds cacheability to the DataSource Utility.

    19  * @class DataSourceCache

    20  * @extends Cache

    21  */    

    22 var DataSourceCache = function() {

    23     DataSourceCache.superclass.constructor.apply(this, arguments);

    24 };

    25 

    26 Y.mix(DataSourceCache, {

    27     /**

    28      * The namespace for the plugin. This will be the property on the host which

    29      * references the plugin instance.

    30      *

    31      * @property NS

    32      * @type String

    33      * @static

    34      * @final

    35      * @value "cache"

    36      */

    37     NS: "cache",

    38 

    39     /**

    40      * Class name.

    41      *

    42      * @property NAME

    43      * @type String

    44      * @static

    45      * @final

    46      * @value "dataSourceCache"

    47      */

    48     NAME: "dataSourceCache",

    49 

    50     /////////////////////////////////////////////////////////////////////////////

    51     //

    52     // DataSourceCache Attributes

    53     //

    54     /////////////////////////////////////////////////////////////////////////////

    55 

    56     ATTRS: {

    57 

    58     }

    59 });

    60 

    61 Y.extend(DataSourceCache, Y.Cache, {

    62     /**

    63     * Internal init() handler.

    64     *

    65     * @method initializer

    66     * @param config {Object} Config object.

    67     * @private

    68     */

    69     initializer: function(config) {

    70         this.doBefore("_defRequestFn", this._beforeDefRequestFn);

    71         this.doBefore("_defResponseFn", this._beforeDefResponseFn);

    72     },

    73 

    74     /**

    75      * First look for cached response, then send request to live data.

    76      *

    77      * @method _beforeDefRequestFn

    78      * @param e {Event.Facade} Event Facade with the following properties:

    79      * <dl>

    80      * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

    81      * <dt>request (Object)</dt> <dd>The request.</dd>

    82      * <dt>callback (Object)</dt> <dd>The callback object.</dd>

    83      * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

    84      * </dl>

    85      * @protected

    86      */

    87     _beforeDefRequestFn: function(e) {

    88         // Is response already in the Cache?

    89         var entry = (this.retrieve(e.request)) || null;

    90         if(entry && entry.response) {

    91             this.get("host").fire("response", Y.mix({response: entry.response}, e));

    92             return new Y.Do.Halt("DataSourceCache plugin halted _defRequestFn");

    93         }

    94     },

    95     

    96     /**

    97      * Adds data to cache before returning data.

    98      *

    99      * @method _beforeDefResponseFn

   100      * @param e {Event.Facade} Event Facade with the following properties:

   101      * <dl>

   102      * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

   103      * <dt>request (Object)</dt> <dd>The request.</dd>

   104      * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

   105      *     <dl>

   106      *         <dt>success (Function)</dt> <dd>Success handler.</dd>

   107      *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

   108      *     </dl>

   109      * </dd>

   110      * <dt>data (Object)</dt> <dd>Raw data.</dd>

   111      * <dt>response (Object)</dt> <dd>Normalized response object with the following properties:

   112      *     <dl>

   113      *         <dt>cached (Object)</dt> <dd>True when response is cached.</dd>

   114      *         <dt>results (Object)</dt> <dd>Parsed results.</dd>

   115      *         <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>

   116      *         <dt>error (Object)</dt> <dd>Error object.</dd>

   117      *     </dl>

   118      * </dd>

   119      * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

   120      * </dl>

   121      * @protected

   122      */

   123      _beforeDefResponseFn: function(e) {

   124         // Add to Cache before returning

   125         if(e.response && !e.response.cached) {

   126             e.response.cached = true;

   127             this.add(e.request, e.response, (e.callback && e.callback.argument));

   128         }

   129      }

   130 });

   131 

   132 Y.namespace('Plugin').DataSourceCache = DataSourceCache;

   133 

   134 

   135 

   136 }, '3.0.0' ,{requires:['datasource-local', 'cache']});