YUI Library Examples: DataTable Control: Integrating Browser History Manager with Server-side Pagination and Sorting

Code for this example

This example contacts a server side script to get the records appropriate for display in the DataTable according to the requested sort order and page. Additionally, each change of page or sort order will be added to the Browser History Manager, allowing bookmarking and the use of the browser's back/forward buttons to navigate through states of the DataTable.

The data

The server-side script delivering the DataTable's records will send the data in the following JSON format:

The markup

CSS

The Browser History Manager markup requires an iframe to support IE6. This is hidden via CSS per the recommendation.

Workflow

To integrate the Browser History Manager with DataTable pagination and sorting, we need to create a few custom functions and insert them into the normal flow of operations. Here's a diagram of how the code below will operate (note the methods in floating boxes are our custom functions):

Flowchart of the DataTable interaction with BHM updating

Javascript

First we set up the DataTable with server-side sorting and pagination, including creation of all dependencies, like a DataSource instance and Paginator instance.

(function () {
    // Create the DataSource
    var myDataSource = new YAHOO.util.DataSource("assets/php/json_proxy.php?");
    myDataSource.responseType = YAHOO.util.DataSource.TYPE_JSON;
    myDataSource.responseSchema = {
        resultsList: "records",
        fields: ["id","name","date","price"],
        metaFields: {
            totalRecords: "totalRecords",
            paginationRecordOffset : "startIndex",
            paginationRowsPerPage : "pageSize",
            sortKey: "sort",
            sortDir: "dir"
        }
    };

// Create the Paginator
    var myPaginator = new YAHOO.widget.Paginator({
        containers : ["dt-pag-nav"],
        template : "{PreviousPageLink} {CurrentPageReport} {NextPageLink} {RowsPerPageDropdown}",
        pageReportTemplate : "Showing items {startIndex} - {endIndex} of {totalRecords}",
        rowsPerPageOptions : [10,25,50,100]
    });
    
    // Define Columns
    var myColumnDefs = [
        {key:"id", label:"ID", sortable:true},
        {key:"name", label:"Name", sortable:true},
        {key:"date", label:"Date", sortable:true},
        {key:"price", label:"Price", sortable:true}
    ];

// DataTable configurations
    var myConfig = {
        paginator : myPaginator,
        dynamicData : true,
        initialLoad : false
    };

// Instantiate DataTable
    var myDataTable = new YAHOO.widget.DataTable(
        "bhmintegration", myColumnDefs, myDataSource, myConfig
    );
    
    // Show loading message while page is being rendered
    myDataTable.showTableMessage(myDataTable.get("MSG_LOADING"), YAHOO.widget.DataTable.CLASS_LOADING);

// Add the instances to the YAHOO.example namespace for inspection
    YAHOO.example.BHMIntegration = {
        myPaginator  : myPaginator,
        myDataSource : myDataSource,
        myDataTable  : myDataTable
    };

The following code integrates the DataTable with the Browser History Manager, which we'll use to remember "states". We'll use the request sent to the server script as the state indicator and custom pagination and sorting handlers to generate new states and pass them to the BHM's navigate method. The handleHistoryNavigation handler will take over from there.

// Integrate with Browser History Manager
    var History = YAHOO.util.History;

// Define a custom function to route sorting through the Browser History Manager
    var handleSorting = function (oColumn) {
        // Calculate next sort direction for given Column
        var sDir = this.getColumnSortDir(oColumn);
        
        // The next state will reflect the new sort values
        // while preserving existing pagination rows-per-page
        // As a best practice, a new sort will reset to page 0
        var newState = generateRequest(0, oColumn.key, sDir, this.get("paginator").getRowsPerPage());

// Pass the state along to the Browser History Manager
        History.navigate("myDataTable", newState);
    };
    myDataTable.sortColumn = handleSorting;

// Define a custom function to route pagination through the Browser History Manager
    var handlePagination = function(state) {
        // The next state will reflect the new pagination values
        // while preserving existing sort values
        // Note that the sort direction needs to be converted from DataTable format to server value
        var sortedBy  = this.get("sortedBy"),
            newState = generateRequest(
            state.recordOffset, sortedBy.key, sortedBy.dir, state.rowsPerPage
        );

// Pass the state along to the Browser History Manager
        History.navigate("myDataTable", newState);
    };
    // First we must unhook the built-in mechanism...
    myPaginator.unsubscribe("changeRequest", myDataTable.onPaginatorChangeRequest);
    // ...then we hook up our custom function
    myPaginator.subscribe("changeRequest", handlePagination, myDataTable, true);

// Update payload data on the fly for tight integration with latest values from server 
    myDataTable.doBeforeLoadData = function(oRequest, oResponse, oPayload) {
        var meta = oResponse.meta;
        oPayload.totalRecords = meta.totalRecords || oPayload.totalRecords;
        oPayload.pagination = {
            rowsPerPage: meta.paginationRowsPerPage || 10,
            recordOffset: meta.paginationRecordOffset || 0
        };
        oPayload.sortedBy = {
            key: meta.sortKey || "id",
            dir: (meta.sortDir) ? "yui-dt-" + meta.sortDir : "yui-dt-asc" // Convert from server value to DataTable format
        };
        return true;
    };
    
    // Returns a request string for consumption by the DataSource
    var generateRequest = function(startIndex,sortKey,dir,results) {
        startIndex = startIndex || 0;
        sortKey   = sortKey || "id";
        dir   = dir   = (dir) ? dir.substring(7) : "asc"; // Converts from DataTable format "yui-dt-[dir]" to server value "[dir]"
        results   = results || 10;
        return "results="+results+"&startIndex="+startIndex+"&sort="+sortKey+"&dir="+dir;
    };

// Called by Browser History Manager to trigger a new state
    var handleHistoryNavigation = function (request) {
        // Sends a new request to the DataSource
        myDataSource.sendRequest(request,{
            success : myDataTable.onDataReturnSetRows,
            failure : myDataTable.onDataReturnSetRows,
            scope : myDataTable,
            argument : {} // Pass in container for population at runtime via doBeforeLoadData
        });
    };

// Calculate the first request
    var initialRequest = History.getBookmarkedState("myDataTable") || // Passed in via URL
                       generateRequest(); // Get default values

// Register the module
    History.register("myDataTable", initialRequest, handleHistoryNavigation);

// Render the first view
    History.onReady(function() {
        // Current state after BHM is initialized is the source of truth for what state to render
        var currentState = History.getCurrentState("myDataTable");
        handleHistoryNavigation(currentState);
    });

// Initialize the Browser History Manager.
    YAHOO.util.History.initialize("yui-history-field", "yui-history-iframe");
})();

Configuration for This Example

You can load the necessary JavaScript and CSS for this example from Yahoo's servers. Click here to load the YUI Dependency Configurator with all of this example's dependencies preconfigured.

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