Subscribing to a Binary subject

The page provides an overview of how to subscribe to a subject of type Binary.

Contents:

Requirements
Overview
Example

Requirements

To use the Binary data type, your Caplin components and libraries must be at least as recent as the versions listed in the table below:

Product versions supporting the Binary data type
Product	Minimum Version
C DataSource API	8.0.12
Java DataSource API	8.0.11
.NET DataSource API	8.0.12
Liberator	8.0.15
Transformer	8.0.8
StreamLink Java	8.0.7
StreamLink JS	8.0.7
StreamLink .NET	8.0.7

Overview

To subscribe to a Binary subject using StreamLink JS, follow the steps below:

Implement the onBinaryUpdate method in your implementation of SubscriptionListener. The method receives an event object of type BinaryEvent. The BinaryEvent.getBinary() method returns the binary object.

var subscriptionListener = {
  ...
  onBinaryUpdate: function (subscription, event) {
    var binaryData = event.getBinary();
    console.log(binaryData.toString());
  }
  ...
};

Subscribe to the Binary subject and connect

streamLink.subscribe("/EXAMPLES/BINARY/AAPL", subscriptionListener);
streamLink.connect();

Example

The StreamLink Live Examples packaged with Liberator include an example of subscribing to binary data.

To view the live example, follow the steps below:

Deploy Liberator to a Deployment Framework
Activate Liberator’s LiberatorWebsite and LiberatorDemoDataSource built-in blades:
```
./dfw activate LiberatorWebsite LiberatorDemoDataSource
```
Start deployed components:
```
./dfw start
```
Open a web browser, and navigate to http://localhost:18080/docs/sljs/interactive/#tutorial/binary-subscription

The source code for the live example is reproduced below:

Example: subscribing to a Binary subject

<!DOCTYPE html>
<html>
<head>
    <script type="text/javascript"
        src="http://localhost:18080/sljs/streamlink.js"></script>
</head>
<body onunload="streamLink.disconnect();">

<p>Binary:</p>

<pre id='display'>No Binary Data Received</pre>

<pre id='displayLog'>Log:</pre>

<script>
    // Instantiate StreamLink.
    var streamLink = caplin.streamlink.StreamLinkFactory.create({
        username: "demouser",
        password: "demopass",
        liberator_urls: "rttp://localhost:18080"
    });

    // Define a subscription listener.
    var binaryListener = {
        onSubscriptionStatus: function (subscription, event) {
            log(event.getSubject() + " is now " + event.getStatus());
        },

        onSubscriptionError: function (subscription, event) {
            log("Error: Subject " + event.getSubject() + " is " + event.getError());
        },

        onBinaryUpdate: function (subscription, event) {
            // onBinaryUpdate is called whenever a value in a binary object is changed.
            render(event.getBinary().toString());
        }
    };

    // Define a function to redraw the binary with all the data.
    var binaryElement = document.getElementById('display');

    function render(binaryString) {
        binaryElement.innerHTML = binaryString;
    }

    // Define a function to write to the log.
    var logArea = document.getElementById("displayLog");

    function log(line) {
        logArea.innerHTML += "\n" + line;
        logArea.scrollTop = logArea.clientHeight;
    }

    // Subscribe and connect.
    streamLink.subscribe("/EXAMPLES/BINARY/DELL", binaryListener);
    streamLink.connect();

</script>
</body>
</html>

See also:

Binary data type