Emitters

The Tracker instance must be initialized with an emitter. This section will go into more depth about the Emitter and how it works under the hood.

Emitter emitter("com.acme", Emitter::Method::POST, Emitter::Protocol::HTTP, 52000, 52000, 500, "sp.db");
Code language: CSS (css)

There are other optional arguments:

Argument Name	Description	Required?
uri	The URI to send events to	Yes
method	The request type to use (GET or POST)	Yes
protocol	The protocol to use (http or https)	Yes
send_limit	The maximum amount of events to send at a time	Yes
byte_limit_post	The byte limit when sending a POST request	Yes
byte_limit_get	The byte limit when sending a GET request	Yes
db_name	Defines the path and file name of the database	Yes

The db_name can be any valid path on your host file system (that can be created with the current user). By default it will create the required files wherever the application is being run from.

5.1 Under the hood

Once the emitter receives an event from the Tracker a few things start to happen:

• The event is added to a local Sqlite3 database (blocking execution)
• A long running daemon thread is started which will continue to send events as long as they can be found in the database (asynchronous)
• The emitter loop will grab a range of events from the database up until the SendLimit as noted _above
• The emitter will send all of these events as determined by the Request, Protocol and ByteLimits
  • Each request is sent in its thread.
• Once sent it will process the results of all the requests sent and will remove all successfully sent events from the database