Integrate Real-Time Access to Elasticsearch in SAPUI5 MVC Apps

In this article we show how to use the CData Connect Server and with the ADO.NET Provider for Elasticsearch (or any of 200+ other ADO.NET Providers) to write SAPUI5 apps that leverage the capabilities of the Elasticsearch API, without writing to a back-end database. The Connect Server is a lightweight Web application that runs on your server and produces OData feeds of Elasticsearch data. OData is the standard for real-time data access over the Web and has built-in support in SAPUI5 and OpenUI5.

Configuring Connect Server

To work with live Elasticsearch data in our SAPUI5 app, we need to connect to Elasticsearch from Connect Server, provide user access to the new virtual database, and create OData endpoints for the Elasticsearch data.

Add a Connect Server User

Create a User to connect to Elasticsearch from SAPUI5 through Connect Server.

1. Click Users -> Add
2. Configure a User
3. Click Save Changes and make note of the Authtoken for the new user

Connect to Elasticsearch from Connect Server

CData Connect Server uses a straightforward, point-and-click interface to connect to data sources and generate APIs.

1. Open Connect Server and click Connections
2. Select "Elasticsearch" from Available Data Sources
3. Enter the necessary authentication properties to connect to Elasticsearch.

   Set the Server and Port connection properties to connect. To authenticate, set the User and Password properties, PKI (public key infrastructure) properties, or both. To use PKI, set the SSLClientCert, SSLClientCertType, SSLClientCertSubject, and SSLClientCertPassword properties.

   The data provider uses X-Pack Security for TLS/SSL and authentication. To connect over TLS/SSL, prefix the Server value with 'https://'. Note: TLS/SSL and client authentication must be enabled on X-Pack to use PKI.

   Once the data provider is connected, X-Pack will then perform user authentication and grant role permissions based on the realms you have configured.

4. Click Save Changes
5. Click Privileges -> Add and add the new user (or an existing user) with the appropriate permissions (SELECT is all that is required for Reveal).

Add Elasticsearch OData Endpoints in Connect Server

After connecting to Elasticsearch, create OData Endpoints for the desired table(s).

1. Click OData -> Tables -> Add Tables
2. Select the Elasticsearch database
3. Select the table(s) you wish to work with and click Next
4. (Optional) Edit the resource to select specific fields and more
5. Save the settings

(Optional) Configure Cross-Origin Resource Sharing (CORS)

When accessing and connecting to multiple domains from an application such as Ajax, there is a possibility of violating the limitations of cross-site scripting. In that case, configure the CORS settings in OData -> Settings.

• Enable cross-origin resource sharing (CORS): ON
• Allow all domains without '*': ON
• Access-Control-Allow-Methods: GET, PUT, POST, OPTIONS
• Access-Control-Allow-Headers: Authorization

Save the changes to the settings.

Create the View

In this article the user views and interacts with Elasticsearch data through an SAPUI5 table control. Table columns will be automatically detected from the metadata retrieved from the Connect Server's API endpoint. We define the following table in a separate View.view.xml file:

<mvc:View
  controllerName="sap.ui.table.sample.OData2.Controller"
  xmlns="sap.ui.table"
  xmlns:mvc="sap.ui.core.mvc"
  xmlns:u="sap.ui.unified"
  xmlns:c="sap.ui.core"
  xmlns:m="sap.m">
  <m:Page
    showHeader="false"
    enableScrolling="true"
    class="sapUiContentPadding">
    <m:content>
      <Table
        id="table"
        selectionMode="MultiToggle"
        visibleRowCount="10"
        enableSelectAll="false"
        rows="{/Orders}"
        threshold="15"
        enableBusyIndicator="true"
        columns="{
          path: 'meta>/dataServices/schema/[${namespace}===\'CData\']/entityType/[${name}===\'Orders\']/property',
          factory: '.columnFactory'
        }">
        <toolbar>
          <m:Toolbar>
            <m:Title text="Elasticsearch Orders"></m:Title>
          </m:Toolbar>
        </toolbar>
        <noData>
          <m:BusyIndicator class="sapUiMediumMargin"/>
        </noData>
      </Table>
    </m:content>
  </m:Page>
</mvc:View>

Create the Model and Controller

In SAPUI5, you do not need to write any OData queries; an ODataModel instance handles the application's data access commands. The Connect Server then translates the queries into Elasticsearch API calls.

The controller processes user input and represents information to the user through a view. Define the controller in a new file, Controller.controller.js. Instantiate the model in the onInit function -- you will need to replace the placeholder values for the serviceUrl to the Connect Server as well as the Authorization header.

For the Authorization header, you will keep the "Basic" as shown and then use a Base64 encoder (such as this one) to generate a token to fill in the second part. You will use the login information for Connect Server in the following format to generate your encoded token -> User:Authtoken

sap.ui.define([
  "sap/ui/core/mvc/Controller",
  "sap/ui/model/odata/v2/ODataModel",
  "sap/ui/model/json/JSONModel",
  "sap/ui/table/Column",
  "sap/m/Text",
], function(Controller, ODataModel, JSONModel, Column, Text ) {
  "use strict";
  

  return Controller.extend("sap.ui.table.sample.OData2.Controller", {
    
    onInit : function () {
      
      var oView = this.getView();
      var oDataModel = new ODataModel({
        serviceUrl: "http://localhost:8080/odata.rsc/",  
        headers: {
            "Authorization":"Basic your-token-here>"
        }
    });
      
      oDataModel.setUseBatch(false);
      oDataModel.getMetaModel().loaded().then(function(){
        oView.setModel(oDataModel.getMetaModel(), "meta");
      });
      oView.setModel(oDataModel);
      
      var oTable = oView.byId("table");
      var oBinding = oTable.getBinding("rows");
      var oBusyIndicator = oTable.getNoData();
      oBinding.attachDataRequested(function(){
      oTable.setNoData(oBusyIndicator);
      });
      oBinding.attachDataReceived(function(){
        oTable.setNoData(null); //use default again ("no data" in case no data is available)
      });
    },
    
    onExit : function () {
    },
    
    columnFactory : function(sId, oContext) {
      var oModel = this.getView().getModel();
      var sName = oContext.getProperty("name");
      var sType = oContext.getProperty("type");
      var iLen = oContext.getProperty("maxLength");
      iLen = iLen ? parseInt(iLen, 10) : 10;
      
      return new Column(sId, {
        sortProperty: sName, 
        filterProperty: sName,
        width: (iLen > 9 ? (iLen > 50 ? 15 : 10) : 5) + "rem",
        label: new sap.m.Label({text: "{/#Orders/" + sName + "/@name}"}),
        hAlign: sType && sType.indexOf("Decimal") >= 0 ? "End" : "Begin",
        template: new Text({text: {path: sName}})
      });
    }
    
  });

});

Describe Application Logic

Create a component that contains the resources of your application. Define the following in Component.js:

sap.ui.define([
  'sap/ui/core/UIComponent'
], function(UIComponent) {
  "use strict";

  return UIComponent.extend("sap.ui.table.sample.OData2.Component", {
    metadata : {
      rootView : "sap.ui.table.sample.OData2.View",
      dependencies : {
        libs : [
          "sap.ui.table",
          "sap.ui.unified",
          "sap.m"
        ]
      },

      config : {
        sample : {
          stretch : true,
          files : [
            "View.view.xml",
            "Controller.controller.js"
          ]
        }
      }
    }
  });

});

Bootstrap OpenUI5 and Launch

To complete the MVC application, simply add the bootstrap and initialization code. Add these directly to index.html:

<!DOCTYPE HTML>

<html>
<head>
  <meta http-equiv="x-ua-compatible" content="ie=edge">
  <meta charset="utf-8"> 
  <title>Elasticsearch Orders</title>
  
  <script id="sap-ui-bootstrap"
    src="https://openui5.hana.ondemand.com/resources/sap-ui-core.js"
    data-sap-ui-libs="sap.m"
    data-sap-ui-theme="sap_bluecrystal"
    data-sap-ui-xx-bindingSyntax="complex"
    data-sap-ui-preload="async"
    data-sap-ui-compatVersion="edge" 
    data-sap-ui-resourceroots='{"sap.ui.table.sample.OData2": "./", "sap.ui.demo.mock": "mockdata"}'>
  </script>
  
  <!-- application launch configuration -->
  <script>
  
      sap.ui.getCore().attachInit(function() {
        new sap.m.App ({
          pages: [
                new sap.m.Page({
                    title: "Elasticsearch Orders", 
                    enableScrolling : false,
                  content: [ new sap.ui.core.ComponentContainer({
                  height : "100%", name : "sap.ui.table.sample.OData2"
                })]
            })
          ]
      }).placeAt("content");
    });

  </script>
</head> 
  <!-- UI Content -->
<body class="sapUiBody" id="content" role="application">
</body> 
</html>

Setting Up A Web Server

To test the project, we can set up a web server. SAPUI5 has its own mock server, and the documentation for setting it up can be found here: https://sapui5.hana.ondemand.com/sdk/#/topic/50897decc9504b2a875fb41d89fd254a

Alternatively, we can use a NodeJS server, like so:

    var fs = require('fs'), http = require('http');

    http.createServer(function (req, res) {
      fs.readFile(__dirname + req.url, function (err,data) {
        if (err) {
          res.writeHead(404);
          res.end(JSON.stringify(err));
          return;
        }
        res.writeHead(200);
        res.end(data);
      });
    }).listen(3000); //we're using port 3000, but you may use a different one
    

The resulting SAPUI5 table control reflects any changes to a table in the remote Elasticsearch data. You can now browse and search current Elasticsearch data.

Free Trial & More Information

If you are interested in connecting to your Elasticsearch data (or data from any of our other supported data sources), sign up for a free trial of CData Connect Server today! For more information on Connect Server and to see what other data sources we support, refer to our CData Connect page.