Bind Live Harvest Data in Wijmo FlexGrid with CData API Server

With CData API Server, easily create OData endpoints for live Harvest data and seamlessly connect and bind them to Wijmo's FlexGrid for real-time, interactive data access without manual data movement.

Wijmo FlexGrid is a lightweight, high-performance JavaScript datagrid for creating responsive, interactive data applications.

With the CData API Server and the Harvest Connector (or any of the 350+ available connectors), you can quickly create APIs that expose live data from multiple sources, using industry standards like OData and Swagger for seamless integration with client-side and server-side controls in Wijmo's FlexGrid.

In this article, we'll use the Wijmo FlexGrid JavaScript components to build a simple HTML page that lets you select tables and columns from Harvest and display the data.

Let's get started!

Prerequisites

CData API Server: Download a free trial here.
Wijmo FlexGrid: No downloads are required for this example, but you can sign up for a free trial here.
An active Harvest account with access to your data.

Overview

Here's a quick overview of the steps we'll follow:

Install the CData API Server, configure a connection to Harvest, and expose OData endpoints.
Bind Wijmo Grid to the live OData feed for real-time data access and interaction.

Step 1: Install the CData API Server and Add a Connection to Harvest

1.1 Install the API Server

If you haven't already, download an installer for your machine from the CData API Server page. Follow the installation instructions to complete the setup.

Once installed, you can start the server in the following ways:

Windows: CData API Server runs as a service by default. Make sure the service is running, then open http://hostname:port (e.g., http://localhost:8080/) in your browser to access the API Server admin console.
Linux/Mac: You can run the server manually or as a service. To start it manually, navigate to the installation directory and run java -jar apiserver.jar.
Alternatively, run service.sh with root privileges to set up API Server as a Linux system service.

1.2 Enable CORS

When your Wijmo Grid application and the CData API Server are hosted on different domains, CORS (Cross-Origin Resource Sharing) must be enabled. To enable CORS in the API Server:

Go to Settings and click the icon to edit CORS settings.
Enable Cross-Origin Resource Sharing (CORS).
Enable Allow all domains without '*' to accept any origin.
In Access-Control-Allow-Origin, enter your Harvest origin domain, or use * to allow all domains (suitable for public APIs).
Enable Access-Control-Allow-Credentials to allow cookies and auth headers.
In Access-Control-Allow-Methods, enter GET, PUT, POST, OPTIONS.
In Access-Control-Allow-Headers, enter Authorization, Content-Type.
Set Access-Control-Max-Age (default: 3600 seconds).
Click Save.

Enabling CORS Settings in the CData API Server

1.3 Add a Harvest Connection in the API Server

Go to Settings and click Add Connection in the top-right.
Select Harvest. If it's not visible, toggle off Only Installed to view all connectors.
Click Install Connector to auto-install. For a manual setup, choose Manual Install and upload the obtained ZIP file.
Once installed, click Harvest to configure connection settings.

Start by setting the Profile connection property to the location of the Harvest Profile on disk (e.g. C:\profiles\Harvest.apip). Next, set the ProfileSettings connection property to the connection string for Harvest (see below).

Harvest API Profile Settings

To authenticate to Harvest, you can use either Token authentication or the OAuth standard. Use Basic authentication to connect to your own data. Use OAuth to allow other users to connect to their data.

Using Token Authentication

To use Token Authentication, set the APIKey to your Harvest Personal Access Token in the ProfileSettings connection property. In addition to APIKey, set your AccountId in ProfileSettings to connect.

Using OAuth Authentication

First, register an OAuth2 application with Harvest. The application can be created from the "Developers" section of Harvest ID.

After setting the following connection properties, you are ready to connect:

ProfileSettings: Set your AccountId in ProfileSettings.
AuthScheme: Set this to OAuth.
OAuthClientId: Set this to the client ID that you specified in your app settings.
OAuthClientSecret: Set this to the client secret that you specified in your app settings.
CallbackURL: Set this to the Redirect URI that you specified in your app settings.
InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to manage how the driver obtains and refreshes the OAuthAccessToken.

Click Save & Test to validate and complete the connection setup.

Adding a Connection in the CData API Server

1.4 Add and Configure Users

To allow secure access to the created OData endpoints, create and configure Users in the API Server.

Go to Users from the navigation pane, then click Add User.
Set a Username and Password.
Select a Role: Select Admin for full access and Query for limited access.
Define user Privileges (GET, POST, PUT, DELETE, etc.).
Click Add User to save.

Once a user is added, an Authtoken is automatically generated. This token can be used in API requests as a secure authentication method instead of a password.

You can also refresh the Authtoken, disable it, or set expiration rules (e.g., number of days until expiry) by enabling the Token Expiration option in the user settings.

'Authtoken' Settings for the Added User in CData API Server

1.5 Add Tables for the Endpoint

To make data from Harvest accessible in Wijmo Grid via OData, you need to expose your desired tables through the API Server. Here's how:

In the API Server, go to API and click Add Table.
Select the Harvest connection and click Next.
Choose the tables you want to expose and click Confirm.

Adding Tables for API Endpoint in CData API Server

1.6 Access the Endpoints in Wijmo FlexGrid

Now that your API is configured, Wijmo FlexGrid can connect to the OData endpoints to display live data. Below are the URL formats for OData endpoints that you can use:

Endpoint		URL
Entity List		http://`address`:`port`/api.rsc/
Table Metadata (e.g., albums)		http://`address`:`port`/api.rsc/albums/$metadata?@json
Table Data (e.g., albums)		http://`address`:`port`/api.rsc/albums

These OData endpoints are now ready to be directly consumed in Wijmo FlexGrid using the URL. Since Wijmo FlexGrid supports OData, you can easily bind live data from Harvest and create dynamic, interactive grids.

The CData API Server supports full OData filtering capabilities. For custom queries and filtered visualizations, you can append standard OData query parameters like $select, $filter, $orderby, $top, and $skip to your requests.

Step 2: Build the Simple Wijmo Grid

You've got the CData API Server up and running now with consumable OData endpoints from your Harvest data. Now let's build a simple Wijmo FlexGrid that lets you select tables and columns and view your data.

Get the CData API Endpoint URL by logging into your CData API Server. Go to API from the left navigation, then click View Endpoints at the top-right.
Copy the URL (e.g., http://localhost:8080/api.rsc).

Getting the API Endpoint URL from CData API Server

Create a new HTML file and give it a name (e.g., Wijmo-Grid.html).
Paste the following code into your HTML file.
Update the following placeholder values at the start of the script section:

yourUsername: Replace with your CData API Server username.
yourPassword: Replace with your CData API Server password.
Your_CData_API_Server_URL: Replace with the full API endpoint URL you copied earlier.


<!DOCTYPE html>
<html lang="en">
<head>

  <meta charset="UTF-8">
  <title>Wijmo Grid with CData API Server</title>

  <!-- Wijmo styles -->
  <link href="https://cdn.mescius.com/wijmo/5.latest/styles/wijmo.min.css" rel="stylesheet" />

  <!-- Wijmo core and controls -->
  <script src="https://cdn.mescius.com/wijmo/5.latest/controls/wijmo.min.js"></script>
  <script src="https://cdn.mescius.com/wijmo/5.latest/controls/wijmo.grid.min.js"></script>
  <script src="https://cdn.mescius.com/wijmo/5.latest/controls/wijmo.input.min.js"></script>
  <script src="https://cdn.mescius.com/wijmo/5.latest/controls/wijmo.odata.min.js"></script>

<style>
    body {
      font-family: Arial, sans-serif;
      margin: 20px;
    }
    h1 {
      color: #00A0FF;
      text-align: center;
    }
    #selectors {
      display: flex;
      flex-wrap: wrap;
      gap: 15px;
      justify-content: center;
      align-items: flex-start;
      margin-bottom: 20px;
    }
    .select-group {
      display: flex;
      flex-direction: column;
      min-width: 200px;
    }
    label {
      font-weight: bold;
      margin-bottom: 5px;
      color: #00A0FF;
    }
    select, button {
      padding: 6px;
      font-size: 14px;
      border: 1px solid #00A0FF;
      border-radius: 4px;
    }
    button {
      background: #00A0FF;
      color: white;
      cursor: pointer;
      height: 40px;
      margin-top: 24px;
    }
    #columnsContainer {
      display: flex;
      flex-direction: column;
      gap: 5px;
      max-height: 150px;
      overflow-y: auto;
      border: 1px solid #00A0FF;
      padding: 8px;
      border-radius: 4px;
    }
    #theGrid {
      margin-top: 20px;
      border: 2px solid #00A0FF;
      height: 500px;
    }
    .wj-header {
      background: #00A0FF !important;
      color: white !important;
      font-weight: bold;
    }
  </style>

</head>
<body>

<h1>Simple Wijmo Grid with CData API Server</h1>

  <div id="selectors">
    <div class="select-group">
      <label for="tableSelect">Select Table</label>
      <select id="tableSelect"></select>
    </div>

    <div class="select-group">
      <label>Select Columns</label>
      <div id="columnsContainer"></div>
    </div>

    <div>
      <button onclick="loadGrid()">Load Grid</button>
    </div>
  </div>

  <div id="theGrid"></div>

<script>
    const username = 'yourUsername';
    const password = 'yourPassword';
    const authHeader = 'Basic ' + btoa(username + ':' + password);
    const serviceUrl = 'Your_CData_API_Server_URL';

    fetch(serviceUrl + '/$metadata', { headers: { Authorization: authHeader } })
      .then(res => res.text())
      .then(text => {
        const parser = new DOMParser();
        const xml = parser.parseFromString(text, 'application/xml');
        const tables = [...xml.getElementsByTagName('EntityType')];
        const select = document.getElementById('tableSelect');
        tables.forEach(t => {
          const name = t.getAttribute('Name');
          const option = document.createElement('option');
          option.value = name;
          option.textContent = name;
          select.appendChild(option);
        });
        loadColumns(); // load columns for the first table
      });

    document.getElementById('tableSelect').addEventListener('change', loadColumns);

    function loadColumns() {
      const table = document.getElementById('tableSelect').value;
      fetch(serviceUrl + '/$metadata', { headers: { Authorization: authHeader } })
        .then(res => res.text())
        .then(text => {
          const parser = new DOMParser();
          const xml = parser.parseFromString(text, 'application/xml');
          const entity = [...xml.getElementsByTagName('EntityType')].find(t => t.getAttribute('Name') === table);
          const columns = [...entity.getElementsByTagName('Property')];
          const container = document.getElementById('columnsContainer');
          container.innerHTML = '';
          columns.forEach(col => {
            const name = col.getAttribute('Name');
            const div = document.createElement('div');
            div.innerHTML = `<label><input type="checkbox" value="${name}" checked> ${name}</label>`;
            container.appendChild(div);
          });
        });
    }

    function loadGrid() {
      const table = document.getElementById('tableSelect').value;
      const selectedCols = [...document.querySelectorAll('#columnsContainer input:checked')].map(i => i.value);

      const odata = new wijmo.odata.ODataCollectionView(serviceUrl, table, {
        requestHeaders: { Authorization: authHeader }
      });

      const grid = new wijmo.grid.FlexGrid('#theGrid', {
        itemsSource: odata,
        autoGenerateColumns: false,
        columns: selectedCols.map(col => ({ binding: col, header: col })),
        selectionMode: 'CellRange',
        allowSorting: true
      });
    }
</script>

</body>
</html>

Open the HTML file in your browser.
Your browser should display the Wijmo FlexGrid. You can select a table and columns to display your data.

Simple Wijmo FlexGrid Displaying API Data

It's that simple. You can build even more complex applications and grids with Wijmo FlexGrid and the CData API Server by connecting to live data from Harvest.

Check out the various frameworks supported by Wijmo at https://developer.mescius.com/wijmo.

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