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.

Flexmonster Data Server has the following advantages:

Reduced browser’s memory usage. Since loading, processing, filtering, and aggregating of the data is made on the server side, Flexmonster Pivot gets the data in a ready-to-show format. Thus, the data is visualized faster, and the browser’s resources are used more efficiently.
Larger datasets. Despite 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 more than 1 GB — the maximum file size depends on your RAM capacity and the number of unique members in the dataset.
Built-in security configurations. The Data Server allows establishing authorized access to data and managing security in a convenient way.
Cross-platform solution. The Data Server is available for popular operating systems: Windows (32-bit and 64-bit), Ubuntu/Linux (64-bit and ARM64), and macOS (64-bit and ARM64).

Flexmonster 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
 },
 ...
]

Prerequisites

Flexmonster CLI
Install it with the following command:
```
npm install -g flexmonster-cli
```

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 also 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 on the client side.
Type. This drop-down 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 should be specified 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 Quick start guide. Your code should look similar to the following example:

let pivot = new Flexmonster({
  container: "pivotContainer",
  componentFolder: "node_modules/flexmonster/",
  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 React

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

<FlexmonsterReact.Pivot
 toolbar={true}
/>

In Vue

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

<Pivot
 ref="pivot"
 toolbar>
</Pivot>

Step 4. Configure the report

On the client side, the report should be configured as follows:

let pivot = new Flexmonster({
  container: "pivotContainer",
  componentFolder: "node_modules/flexmonster/",
  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 3 (e.g., "index-json").

When Flexmonster Pivot requests the data, Flexmonster Data Server sends the response and then caches it. In case the component sends the same request once again, the server responds with the data from its cache. The Data Server clears the cache when restarted.

The Data Server’s cache has a memory limit. When the cache does not have enough memory for a new response, the Data Server server deletes one of the previously cached responses.

Note You can manage the cache size via the Cache size limit configuration.

What’s next?

You may be interested in the following articles: