--- schema_version: "1" id: b12093bf2b9f3a9836c67bae14574b94b533e30b81347d5d38f19c714210674f title: Sample Code for Using Lightning Message Service with Open CTI collection: developer version: current locale: en-us portal_url: https://docs.salesforce.com/developer/current/en-us/service-cloud/api-cti/guides/sforce-api-cti-sample-lex-message-service.md canonical_url: https://developer.salesforce.com/docs/service/api-cti/guide/sforce-api-cti-sample-lex-message-service.html source_site: developer.salesforce.com content_type: documentation content_hash: 2d1375a89e2fda526884e2c84ff2b5d3c5f882b055502a1bac2ca9991232c63f products: - Open CTI Developer Guide - Service Cloud Developer Content --- # Sample Code for Using Lightning Message Service with Open CTI You can use the Lightning Message Service API to communicate with an Open CTI softphone. This example displays three buttons that subscribe, publish, and remove a message channel `servicedev1_SampleMC__c`. To use Open CTI, you must reference either `opencti.js` or `opencti_min.js` version 47.0 on your softphone adapter page. If you don't have these files, your Salesforce representative can provide them. In the `` of the HTML file, include the filepath for `opencti_min.js`. First, define a variable for the name of your message channel in the JavaScript section of your code. Here, we assign the message channel string `SAMPLEMC_c` to the variable `SAMPLEMC`. Next, create the variable `SAMPLEMC_SUBSCRIPTION` to hold the subscription object and assign it a null value. The `subscribeToSampleMC()` method first checks whether the subscription variable is empty. If the method is empty, it calls the `sforce.opencti.subscribe()` method. The `sforce.opencti.subscribe()` method has three parameters: - `channelName` - : The name of the message channel. - `listener` - : The listener function that’s invoked when a message is sent on the message channel. - `callback` - : The function that receives the subscription object. Assign this value to a variable such as `SAMPLEMC_SUBSCRIPTION`. The `subscribeToSampleMC()` method sets the `` tag in the HTML to _true_. Similarly, the `unsubscribeToSampleMC()` method checks whether there is a subscription object. If so, it calls `sforce.opencti.unsubscribe()`. The method `sforce.opencti.unsubscribe()` has two parameters: - subscription - : The subscription object that you want to unsubscribe from. - callback - : The function that handles the success or error output. The `unsubscribeToSampleMC()` method sets the`` tag in the HTML to _false_. The `publishSampleMC()` method is passed the message content that we want to publish. A message is a serialized JSON object. You can pass data such as strings, numbers, objects, and Boolean values. A message cannot contain functions and symbols. In this example, the message contains three strings: - Name of the sender, “LightningMessageService_OpenCTI_TestPage” - Type of message, “SampleMC” - Time when the message was sent The `publishSampleMC()` method calls `sforce.opencti.publish()` method, which takes three parameters: - channelName - : The name of the message channel to publish to. - message - : The message to publish as a serialized JSON object. - callback - : The function that handles the success or error output. The HTML markup displays the message channel’s name, indicates whether the channel is subscribed, and shows buttons to subscribe, unsubscribe, and publish on the channel. When clicked, these buttons call the respective `subscribeToSampleMC()`, `unsubscribeToSampleMC()`, and `publishSampleMC()` functions. The text area with the `id` set to `opencti_testMessageTextArea` shows the message text. ## Example ```html

MessageChannel: SampleMC

Subscribed: false

Received message:

</div>
	</body>
</html>

```

## Use Message Channels Created Within Your Org

Here’s an example that shows how to use a Lightning Message Channel developed within your org.

```apex
<apex:page>
    <script>
        var SAMPLEMC = "SAMPLEMC__c";
    </script>
</apex:page>

```

Here, a custom Lightning Message Channel is referenced by its name `SAMPLEMC__c`. The syntax refers to a custom instance of the LightningMessageChannel metadata type. The `__c`suffix indicates that it’s a custom, but note that it is not a custom object. For more information, see [Create a Message Channel](https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/message_channel_publish.htm).

If your org has a namespace, don’t include it in your message channel name. For example, if your org’s namespace is _MyNamespace_, then the message channel name remains `SAMPLEMC__c`.

## Use Message Channels Created Outside Your Org

To use Lightning Message Channels from packages created by developers outside of your org, reference them with the syntax `Namespace_name__c`. For example, if `SAMPLEMC` was not local to your org and came from a package with the namespace `SamplePackageNamespace`, the syntax would be `SamplePackageNamespace_SAMPLEMC_c`.