Use the plug() method to initialize the DataSourceCache plugin and point the configuration value cache to Y.CacheOffline to enable offline caching. The configuration value expires can be set to change how soon the data expires.

YUI().use("datasource", "dataschema", "cache", function(Y) {
    var callback = {
            success: function (e) { /* output to screen */ },
            failure: function (e) { /* output to screen */ }
        },

        myDataSource = new Y.DataSource.Get({
            source: "https://api.github.com/users/",

            // this is only needed because the query appends the url
            // rather than the url's query params
            generateRequestCallback: function (guid) {
                return '/repos?callback=YUI.Env.DataSource.callbacks.' + guid;
            }
        }),

    myDataSource.plug(Y.Plugin.DataSourceJSONSchema, {
        schema: {
            resultListLocator: "data",
            resultFields: ["name"]
        }
    });

    // Enable offline data caching by pointing to Y.CacheOffline.
    // For demonstration purposes, data is set to expire after 10 seconds
    myDataSource.plug(Y.Plugin.DataSourceCache, {
        cache: Y.CacheOffline,
        expires: 60000, // 1 min.
        max: 5
    });

    // Retrieves from server. Adds to cache
    myDataSource.sendRequest({
        request : "lsmith",
        callback: callback
    });

    // Retrieves from server. Adds to cache
    myDataSource.sendRequest({
        request : "davglass",
        callback: callback
    });

    // Retrieves from cache if requested within 5 seconds
    myDataSource.sendRequest({
        request : "lsmith",
        callback: callback
    });

    // ... wait 60 seconds ...

    // Cached data has expired. Retrieves from server. Adds to cache.
    myDataSource.sendRequest({
        request : "davglass",
        callback: callback
    });
});

Full Example Source Listing

<form id="demo" action="http://search.yahoo.com/search">
<h6>Look up github repositories by username (ex. lsmith, davglass, or rgrove):</h6>
<input type="input" id="demo_input_query" name="p">
<input type="submit" id="demo_query_retrieve" value="Retrieve data">
<input type="button" id="demo_cache_clear" value="Clear cache">
<div id="demo_output_response" class="output"></div>
</form>



<script type="text/javascript">
YUI().use("json-stringify","node", "datasource-get", "datasource-jsonschema", "cache", "datasource-cache", "datatype-date", function (Y) {
var output = Y.one("#demo_output_response"),
    source = "remote source",

    myDataSource = new Y.DataSource.Get({
        source:"https://api.github.com/users/",
        generateRequestCallback: function (guid) {
            return '/repos?callback=YUI.Env.DataSource.callbacks.' + guid;
        }
    }),

    callback = {
        success: function(e){
            var when = Y.DataType.Date.format(new Date(), {format:"%F %r"}),
                data = Y.JSON.stringify(e.response, null, 2);

            output.setHTML(
                "<p>[" + when + "] Retrieved from " +
                "<strong>" + source + "</strong></p>" +
                "<pre>" +
                    data.replace(/&/g,"&amp;")
                        .replace(/</g,"&lt;")
                        .replace(/>/g,"&gt;") +
                "</pre>");
        },
        failure: function(e){
            var when = Y.DataType.Date.format(new Date(), {format:"%F %r"}),
                message = /fields retrieval/.test(e.error.message) ?
                    "User not found" : e.error.message;

            output.setHTML(
                "<p>[" + when + "] Could not retrieve data: " +
                    "<em>" + message + "</em>" +
                "</p>");
        }
    };

myDataSource.plug(Y.Plugin.DataSourceJSONSchema, {
    schema: {
        resultListLocator: "data",
        resultFields: ["name"]
    }
});

myDataSource.plug(Y.Plugin.DataSourceCache, {
    cache: Y.CacheOffline,
    expires: 60000, // 1 min.
    max:5
});
myDataSource.cache.on("retrieve", function(){
    source = "cache";
});

Y.one("#demo_cache_clear").on("click", function(){
    var when = Y.DataType.Date.format(new Date(), {format:"%F %r"});

    myDataSource.cache.flush();
    output.setHTML("<p>[" + when + "] Cache cleared.</p>");
});

Y.on("submit", function(e){
    e.halt();
    var query = encodeURIComponent(
                    Y.one("#demo_input_query")
                        .get("value")
                        .replace(/"/g,'\\"')
                        .replace(/\W/g, ''));

    if(query) {
        source = "remote source";
        myDataSource.sendRequest({
            request:query,
            callback:callback
        });
    } else {
        output.setHTML("<p>Please enter a query.</p>");
    }
}, "#demo");
});
</script>