Connecting to JSON using Flexmonster Data Server

In the previous article, we described how to connect the pivot table to the JSON data source. To gain even better performance while working with JSON datasets, use Flexmonster Data Server — a special server developed by Flexmonster. This server aggregates your data and then passes it to Flexmonster Pivot in a ready-to-show format.

Advantages of Flexmonster Data Server

Larger datasets. Although Flexmonster Pivot can connect to a JSON file directly, the browser’s capability limits the size of a file (on average, up to 100 MB). Flexmonster Data Server can process files larger than 1 GB — the maximum file size depends on your RAM capacity and the number of unique members in the dataset.
Saves browser resources. All manipulations with data are performed by the server, resulting in faster data visualization and more efficient use of the browser's resources.
Built-in security and authorization. The Data Server provides a convenient way of managing security and establishing authorized access to data.
Cross-platform support. Flexmonster Data Server is available for Windows (32-bit and 64-bit), macOS (64-bit and ARM64), and Ubuntu/Linux (64-bit and ARM64).

Prerequisites

Flexmonster CLI
Install it with the following command:
```
npm install -g flexmonster-cli
```
JSON data in the supported format
The Data Server supports only a specific JSON format — an array of objects, where each object is an unordered set of "key": "value" pairs. Here is an example:
```
[
  {
    "Color" : "green",
    "Country" : "Canada",
    "State" : "Ontario",
    "City" : "Toronto",
    "Price" : 174,
    "Quantity" : 22
  },
  ...
]
```

Now follow the steps below to connect to JSON using the Data Server.

Step 1. Install Flexmonster Data Server

Get the Data Server with the flexmonster add fds command:

flexmonster add fds -r

This command installs and runs the Data Server as a Windows/Unix service. Besides, the command installs Flexmonster Admin Panel — a graphical user interface for the Data Server.

The Data Server's files can be found in the flexmonster-data-server/ folder in your working directory.

There are also alternative ways to install the Data Server:

Step 2. Add a new index

Now let's create a new index for the file with your data.

Open Flexmonster Admin Panel and go to Indexes > Add New Index. Then, fill in the following fields:

Name. This field defines the index name. It will be used to configure the connection in Flexmonster Pivot.
Type. This dropdown menu contains possible data source types. In this case, select JSON.
Path to file. In this field, specify the path to the file with your data. You can click the folder icon to choose the needed file using Explorer.
Refresh time. It defines how often the Data Server should reload the data from the file. The refresh time must be set in minutes.
By default, the refresh time is 0, which means the Data Server will not reload the data.

Your configurations should look similar to the following:

When the index configuration is complete, click Create. The index will be automatically added to your index pool.

Note By default, the Data Server resolves data types for all fields automatically. If you need to set data types for some fields manually, edit your index and configure the mapping for it.

Step 3. Embed the component into your webpage

If Flexmonster is not yet embedded, set up an empty component in your webpage:

In pure JavaScript

Complete the Integrating Flexmonster guide. Your code should look similar to the following example:

const pivot = new Flexmonster({
  container: "pivotContainer",
  toolbar: true
});

In React

Complete the Integration with React guide. Your code should look similar to the following example:

<FlexmonsterReact.Pivot
 toolbar={true}
/>

In Angular

Complete the Integration with Angular guide. Your code should look similar to the following example:

<fm-pivot
 [toolbar]="true">
</fm-pivot>

In Vue

Complete the Integration with Vue guide. Your code should look similar to the following example:

<Pivot
 toolbar
/>

Step 4. Configure the report

In Flexmonster Pivot, the report should be configured as follows:

const pivot = new Flexmonster({
  container: "pivotContainer",
  toolbar: true,
  report: {
    dataSource: {
      type: "api",
      url: "http://localhost:9500",
      index: "index-json"
    }
  }
});

Note The index must match the name of the index defined in step 2 (e.g., "index-json").

About response caching

When Flexmonster Pivot requests data, Flexmonster Data Server sends a response and then caches it. If the component sends the same request again, the server responds with the data from its cache.

The Data Server’s cache has a limit. When the cache does not have enough space for a new response, the Data Server deletes one of the previously cached responses. See how to manage the cache size for the Data Server as a service, as a console application, or as a DLL.

The Data Server clears the cache when restarted.

What’s next?

You may be interested in the following articles:

Changes to Flexmonster Software License Agreement