DataBind Wijmo Grid to Kafka Data

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

Set Up the API Server

Follow the steps below to begin producing secure Kafka 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 Kafka

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

Set BootstrapServers and the Topic properties to specify the address of your Apache Kafka server, as well as the topic you would like to interact with.

Authorization Mechanisms

• SASL Plain: The User and Password properties should be specified. AuthScheme should be set to 'Plain'.
• SASL SSL: The User and Password properties should be specified. AuthScheme should be set to 'Scram'. UseSSL should be set to true.
• SSL: The SSLCert and SSLCertPassword properties should be specified. UseSSL should be set to true.
• Kerberos: The User and Password properties should be specified. AuthScheme should be set to 'Kerberos'.

You may be required to trust the server certificate. In such cases, specify the TrustStorePath and the TrustStorePassword if necessary.

You can then choose the Kafka entities you want to allow the API Server to access by clicking Settings -> Resources. This article uses SampleTable_1 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 Kafka 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 sampletable_1View = new wijmo.data.ODataView("http://MyServer:MyPort/api.rsc/SampleTable_1", {
     ajax: {
       dataType: "jsonp", 
       username: "MyUser",
       password: "MyAuthtoken",
       data: { "$inlinecount": null }
     },
     pageSize: 10
   });
     sampletable_1View.refresh();
     sampletable_1View.nextPage();
     this.sampletable_1 = sampletable_1View;
     this.prevPage = function () {sampletable_1View.prevPage();};
     this.nextPage = function () {sampletable_1View.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 Kafka Data in Real Time</h2>
   
   <h3>SampleTable_1</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: sampletable_1, 
     showFilter: true, 
     allowPaging: true,
     pagerSettings: { position: 'none'},
     columnsAutogenerationMode: 'append',
   }" >
   </table>   
   

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