DataBind Wijmo Grid to Impala Data

The API Server, when paired with the ADO.NET Provider for Impala (or any of 200+ other ADO.NET Providers), provides Impala data as Web services, which enable connectivity to live data. This article shows how to consume JSONP-formatted Impala data from a Wijmo Grid.

Set Up the API Server

Follow the steps below to begin producing secure Impala OData services:

Deploy

The API Server runs on your own server. On Windows, you can deploy using the stand-alone server or IIS. On a Java servlet container, drop in the API Server WAR file. See the help documentation for more information and how-tos.

The API Server is also easy to deploy on Microsoft Azure, Amazon EC2, and Heroku.

Connect to Impala

After you deploy the API Server and the ADO.NET Provider for Impala, provide authentication values and other connection properties needed to connect to Impala by clicking Settings -> Connections and adding a new connection in the API Server administration console.

In order to connect to Apache Impala, set the Server, Port, and ProtocolVersion. You may optionally specify a default Database. To connect using alternative methods, such as NOSASL, LDAP, or Kerberos, refer to the online Help documentation.

You can then choose the Impala entities you want to allow the API Server to access by clicking Settings -> Resources. This article uses Customers as an example.

Authorize API Server Users

After determining the OData services you want to produce, authorize users by clicking Settings -> Users. The API Server uses authtoken-based authentication and supports the major authentication schemes. Access can also be restricted based on IP address; by default only connections to the local machine are allowed. You can authenticate as well as encrypt connections with SSL.

Create a Real-Time Grid

Follow the steps below to consume Impala data from the Wijmo JavaScript controls:

1. Load the required Wijmo, jQuery, and Knockout libraries:

   
   <script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
   <script src="http://code.jquery.com/ui/1.11.0/jquery-ui.min.js"></script>
     
   <!--Theme-->
   <link href="http://cdn.wijmo.com/themes/aristo/jquery-wijmo.css" rel="stylesheet" type="text/css">
     
   <!--Wijmo Widgets CSS-->
   <link href="http://cdn.wijmo.com/jquery.wijmo-pro.all.3.20161.90.min.css" rel="stylesheet" type="text/css">
     
   <!--Wijmo Widgets JavaScript-->
   <script src="http://cdn.wijmo.com/jquery.wijmo-open.all.3.20161.90.min.js"></script>
   <script src="http://cdn.wijmo.com/jquery.wijmo-pro.all.3.20161.90.min.js"></script>
   <script src="http://cdn.wijmo.com/interop/wijmo.data.ajax.3.20161.90.js"></script>
    
   <!--Knockout JS Library-->
   <!-- Both of the links below can work -->
   <script src="http://cdn.wijmo.com/wijmo/external/knockout-2.2.0.js"></script> 
   <!--<script src="http://cdn.wijmo.com/amd-js/3.20161.90/knockout-3.1.0.js"></script>--> 
   
   <!--Wijmo Knockout Integration Library-->
   <script src="http://cdn.wijmo.com/interop/knockout.wijmo.3.20161.90.js"></script>
   

2. Create a ViewModel and connect to it using the ODataView. You will need to replace the placeholder values for the URL of the API Server, an API Server user, and the authtoken for that user.

   
   <script id="scriptInit">
   $.support.cors = true;
   var viewModel;
   
   function ViewModel() {
     var customersView = new wijmo.data.ODataView("http://MyServer:MyPort/api.rsc/Customers", {
     ajax: {
       dataType: "jsonp", 
       username: "MyUser",
       password: "MyAuthtoken",
       data: { "$inlinecount": null }
     },
     pageSize: 10
   });
     customersView.refresh();
     customersView.nextPage();
     this.customers = customersView;
     this.prevPage = function () {customersView.prevPage();};
     this.nextPage = function () {customersView.nextPage();};
   }
   
   $(document).ready(function () {
      viewModel = new ViewModel();
      ko.applyBindings(viewModel, $(".container").get(0));
   });
   </script>
   

3. DataBind: Below is a simple table with some paging buttons, which you can paste into the body section of your markup.

   
   <h2>Connect to Live Impala Data in Real Time</h2>
   
   <h3>Customers</h3>
   <div>
     <button title="previous page" class="pagebuttons" data-bind="click: prevPage, button: {}"><span class="ui-icon ui-icon-seek-prev" /></button>
     <button title="next page" class="pagebuttons" data-bind="click: nextPage, button: {}"><span class="ui-icon ui-icon-seek-next" /></button>
   </div>
   <table id="demo-grid" data-bind="wijgrid: { 
     data: customers, 
     showFilter: true, 
     allowPaging: true,
     pagerSettings: { position: 'none'},
     columnsAutogenerationMode: 'append',
   }" >
   </table>   
   

Below is the resulting grid. You can filter and sort through pages of Impala data.