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: 3.0.0b1

     6 build: 1163

     7 */

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

     9 

    10 /**

    11  * Provides a DataSource implementation which can be used to retrieve data via the Get Utility.

    12  *

    13  * @module datasource

    14  * @submodule datasource-get

    15  */

    16 

    17 /**

    18  * Get Utility subclass for the DataSource Utility.

    19  * @class DataSource.Get

    20  * @extends DataSource.Local

    21  * @constructor

    22  */    

    23 var DSGet = function() {

    24     DSGet.superclass.constructor.apply(this, arguments);

    25 };

    26     

    27 

    28     /////////////////////////////////////////////////////////////////////////////

    29     //

    30     // DataSource.Get static properties

    31     //

    32     /////////////////////////////////////////////////////////////////////////////

    33 Y.mix(DSGet, {

    34     /**

    35      * Class name.

    36      *

    37      * @property NAME

    38      * @type String

    39      * @static     

    40      * @final

    41      * @value "dataSourceGet"

    42      */

    43     NAME: "dataSourceGet",

    44 

    45 

    46     /////////////////////////////////////////////////////////////////////////////

    47     //

    48     // DataSource.Get Attributes

    49     //

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

    51 

    52     ATTRS: {

    53         /**

    54          * Pointer to Get Utility.

    55          *

    56          * @attribute get

    57          * @type Y.Get

    58          * @default Y.Get

    59          */

    60         get: {

    61             value: Y.Get,

    62             cloneDefaultValue: false

    63         },

    64 

    65 /**

    66  * Defines request/response management in the following manner:

    67  * <dl>

    68  *     <!--<dt>queueRequests</dt>

    69  *     <dd>If a request is already in progress, wait until response is returned before sending the next request.</dd>

    70  *     <dt>cancelStaleRequests</dt>

    71  *     <dd>If a request is already in progress, cancel it before sending the next request.</dd>-->

    72  *     <dt>ignoreStaleResponses</dt>

    73  *     <dd>Send all requests, but handle only the response for the most recently sent request.</dd>

    74  *     <dt>allowAll</dt>

    75  *     <dd>Send all requests and handle all responses.</dd>

    76  * </dl>

    77  *

    78  * @attribute asyncMode

    79  * @type String

    80  * @default "allowAll"

    81  */

    82 asyncMode: {

    83     value: "allowAll"

    84 },

    85 

    86 /**

    87  * Callback string parameter name sent to the remote script. By default,

    88  * requests are sent to

    89  * <URI>?<scriptCallbackParam>=callbackFunction

    90  *

    91  * @attribute scriptCallbackParam

    92  * @type String

    93  * @default "callback"

    94  */

    95 scriptCallbackParam : {

    96     value: "callback"

    97 },

    98 

    99 /**

   100  * Accepts the DataSource instance and a callback ID, and returns a callback

   101  * param/value string that gets appended to the script URI. Implementers

   102  * can customize this string to match their server's query syntax.

   103  *

   104  * @attribute generateRequestCallback

   105  * @type Function

   106  */

   107 generateRequestCallback : {

   108     value: function(self, id) {

   109         return "&" + self.get("scriptCallbackParam") + "=YUI.Env.DataSource.callbacks["+id+"]" ;

   110     }

   111 }

   112 

   113 

   114 

   115 

   116 

   117     },

   118 

   119     /**

   120      * Global array of callback functions, one for each request sent.

   121      *

   122      * @property callbacks

   123      * @type Function[]

   124      * @static

   125      */

   126     callbacks : [],

   127 

   128     /**

   129      * Unique ID to track requests.

   130      *

   131      * @property _tId

   132      * @type Number

   133      * @private

   134      * @static

   135      */

   136     _tId : 0

   137 });

   138     

   139 Y.extend(DSGet, Y.DataSource.Local, {

   140     /**

   141      * Passes query string to Get Utility. Fires <code>response</code> event when

   142      * response is received asynchronously.

   143      *

   144      * @method _defRequestFn

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

   146      * <dl>

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

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

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

   150      *     <dl>

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

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

   153      *     </dl>

   154      * </dd>

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

   156      * </dl>

   157      * @protected

   158      */

   159     _defRequestFn: function(e) {

   160         var uri = this.get("source"),

   161             get = this.get("get"),

   162             id = DSGet._tId++,

   163             self = this;

   164             

   165 

   166 

   167 

   168 

   169 

   170 

   171 

   172 

   173 

   174 

   175 

   176 

   177     // Dynamically add handler function with a closure to the callback stack

   178     YUI.Env.DataSource.callbacks[id] = Y.rbind(function(response) {

   179         if((self.get("asyncMode") !== "ignoreStaleResponses")||

   180                 (id === DSGet.callbacks.length-1)) { // Must ignore stale responses

   181 

   182             self.fire("data", Y.mix({data:response}, e));

   183         }

   184         else {

   185             Y.log("DataSource ignored stale response for id " + e.tId + "(" + e.request + ")", "info", "datasource-get");

   186         }

   187 

   188         delete DSGet.callbacks[id];

   189     }, this, id);

   190 

   191     // We are now creating a request

   192     uri += e.request + this.get("generateRequestCallback")(this, id);

   193     //uri = this.doBefore(sUri);

   194     Y.log("DataSource is querying URL " + uri, "info", "datasource-get");

   195     get.script(uri, {

   196         autopurge: true,

   197         // Works in Firefox only....

   198         onFailure: Y.bind(function(e) {

   199             e.error = new Error("Script node data failure");

   200             this.fire("error", e);

   201         }, this, e)

   202     });

   203 

   204 

   205 

   206 

   207 

   208 

   209 

   210 

   211 

   212 

   213 

   214 

   215 

   216 

   217 

   218         return e.tId;

   219     }

   220 });

   221   

   222 Y.DataSource.Get = DSGet;

   223 YUI.namespace("Env.DataSource.callbacks");

   224     

   225 

   226 

   227 

   228 }, '3.0.0b1' ,{requires:['datasource-local', 'get']});