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").

See the full list of Flexmonster properties used to configure the dataSource object.

List of supported configuration parameters

When connecting to data using Flexmonster Data Server, you can use the following properties of the DataSourceObject:

List of properties

Property/Type	Description
type String	The data source type. When connecting to data using Flexmonster Data Server, set the `type` to `"api"`.
url String	The URL to Flexmonster Data Server.
index String	The dataset identifier.
mapping MappingObject \| String	optional Defines how fields from the data source are treated and presented within the component. For example, you can specify the field’s captions, define a type for a field, configure multilevel hierarchies, etc. Read more in the Mapping guide. Can be either an inline MappingObject or a URL to a JSON file with the mapping Live example.
requestHeaders Object	optional Adds custom request headers. Consists of `"key": "value"` pairs, where `"key"` is a header name and `"value"` is its value Live example. Note The `requestHeaders` property is not saved when obtaining the report via `save()` and `getReport()` API calls.
singleEndpoint Boolean	optional When set to `true`, all Flexmonster Pivot’s requests are sent to a single endpoint specified in the url property. Default value: `false`.
withCredentials Boolean	optional Indicates whether cross-site `Access-Control` requests should be made using credentials such as authorization headers (`true`) or not (`false`). For more details, refer to MDN web docs. Setting the `withCredentials` flag to `true` is recommended when using Windows authentication and other types of server authentication. When set to `false`, the browser does not ask for credentials and does not include them in outgoing requests. Default value: `false`.
concurrentRequests Boolean	optional When set to `false`, Flexmonster sends a request for each expand/drill-down separately and waits for the Data Server’s response before sending a new request. This can result in slow performance when there are a lot of expands/drill-downs in the report. When the `concurrentRequests` is `true`, Flexmonster sends requests for expands/drill-downs of a particular level simultaneously. To get the best performance, enable the HTTP/2 protocol in the Data Server. Default value: `false`.

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