Streaming API Developer Guide

Getting Started with Streaming API
Code Examples
Example: Subscribe to and Replay Events Using a Java Client (EMP Connector)
Prerequisites
Step 1: Create an Object
Step 2: Create a PushTopic (Legacy)
Step 3: Download and Build the Project
Step 4: Use the Connector with Username and Password Login
(Optional) Step 5: Use the Connector with OAuth Bearer Token Login
Learn More About EMP Connector
Example: Subscribe to and Replay Events Using a Lightning Component
Example: Interactive Visualforce Page without Replay
Example: Authentication
Client Connection Considerations
PushTopic Events (Legacy)
Generic Events (Legacy)
Monitoring Event Usage
PDF

Note: This release is in preview. Features described here don’t become generally available until the latest general availability date that Salesforce announces for this release. Before then, and where features are noted as beta, pilot, or developer preview, we can’t guarantee general availability within any particular time frame or at all. Make your purchase decisions only on the basis of generally available products and features.

Step 4: Use the Connector with Username and Password Login

Now that you’ve downloaded and built EMP Connector, use it to connect to CometD and subscribe to the PushTopic.
Let’s run an example that uses username and password login.
  1. In the /src/main/java/com/salesforce/emp/connector/example folder, open the LoginExample.java source file.
  2. Run the LoginExample class and provide arguments.
    1. In Package Explorer, navigate to the LoginExample.java file. Right-click the file, and select Run As | Run Configurations.
    2. On the Arguments tab, add values for the following arguments, separated by a space.
      Argument Value
      username Username of the logged-in user
      password Password for the username (or logged-in user)
      channel The channel name for the PushTopic: /topic/InvoiceStatementUpdates

      This quick start is based on a PushTopic event. Alternatively, you can use EMP Connector to listen to any event type. The following lists channel name formats for a sample of streaming events available in the Lightning Platform.

      Platform event

      For a custom platform event—/event/EventName__e

      For a standard platform event—/event/EventName

      For a custom channel—/event/ChannelName__chn

      Change Data Capture event

      For all change events—/data/ChangeEvents

      For a specific standard object—/data/ObjectNameChangeEvent

      For a specific custom object—/data/CustomObjectName__ChangeEvent

      For a custom channel—/data/ChannelName__chn

      PushTopic event

      /topic/PushTopicName

      Generic event

      /u/notifications/GenericStreamingChannel
    3. Click Run.

    The sample is now subscribed to the event channel and is listening to event notifications. As soon as an event notification is published and received, the tool prints it to the console.

    Optionally, to receive different events, you can include a replay ID as the last argument. Valid values are:
    • –1 — Get all new events sent after subscription. This option is the default.
    • –2 — Get all new events sent after subscription and all past events within the retention window. Use -2 sparingly. If a large volume of event messages is stored, retrieving all event messages can slow performance.
    • Specific number — Get all events that occurred after the event with the specified replay ID.
  3. In a browser window, create or modify an invoice statement. After you create or change data that corresponds to the query in your PushTopic, the output looks similar to the following. 
    1Subscribed: Subscription [/topic/InvoiceStatementUpdates:-1]
2Received:
3{event={createdDate=2016-12-12T22:31:48.035Z, replayId=1, type=created}, sobject={Status__c=Open, Id=a070P00000pn0hyQAA, Name=INV-0001, Description__c=blah}}
4Received:
5{event={createdDate=2016-12-12T22:32:06.440Z, replayId=2, type=updated}, sobject={Status__c=Negotiating, Id=a070P00000pn0hyQAA, Name=INV-0001, Description__c=blah}}
6Received:
7{event={createdDate=2016-12-12T22:32:57.404Z, replayId=3, type=created}, sobject={Status__c=Open, Id=a070P00000pn0lfQAA, Name=INV-0002, Description__c=Laptops and accessories.}}

    If you’re listening to another event type, the output would look a bit different. Some events require that you publish the notification instead of Salesforce, such as with platform events.

    Note

Generally, don’t handle usernames and passwords of others when running code in production. In a production environment, delegate the login to OAuth. The next step connects to Streaming API with OAuth.