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Almond Jupyter API

The Almond Jupyter API can be accessed via an instance of almond.api.JupyterAPI. Such an instance is created by almond upon start-up. This instance accessible via the kernel variable and in the implicit scope via e.g. implicitly[almond.api.JupyterAPI].

JupyterAPI

almond.api.JupyterAPI allows to

Request input

Call stdin on JupyterAPI to request user input, e.g.

kernel.stdin() // clear text input
kernel.stdin(prompt = ">> ", password = true) // password input, with custom prompt

Display data

The publish field, of type almond.interpreter.api.OutputHandler, has numerous methods to push display data to the front-end.

The most generic is display, accepting a almond.api.DisplayData.

kernel.publish.display(
  almond.interpreter.api.DisplayData(
    Map(
      // if we set up an extension for application/myapp+json, first element should be picked
      "application/myapp+json" -> """{"a": "A"}""",
      // else, text/html should be displayed
      "text/html" -> "<b>A</b>"
    )
  )
)

OutputHandler also has helper methods to push HTML straightaway.

for (i <- 1 to 10) {
  kernel.publish.html(s"Got item <b>#$i</b>")
  Thread.sleep((200.0 + 200.0 * scala.util.Random.nextGaussian).toLong max 0L)
}

Updatable display data

If passed an id, when pushing some display data, OutputHandler allows to update that data later.

val id = java.util.UUID.randomUUID().toString
kernel.publish.html("Starting", id)

for (i <- 1 to 10) {
  Thread.sleep((200.0 + 200.0 * scala.util.Random.nextGaussian).toLong max 0L)
  kernel.publish.updateHtml(s"Got item <b>#$i</b>", id)
}

kernel.publish.updateHtml("Got all items", id)

Comm messages

Comm messages are part of the Jupyter messaging protocol. They allow the exchange of arbitrary messages between code running in the front-end (typically JavaScript code) and kernels.

The comm API can be used to receive messages, or send them.

kernel.comm.receiver allows to register a target to receive messages from the front-end, like

val id = java.util.UUID.randomUUID().toString
kernel.publish.html("Waiting", id)

kernel.comm.receiver("A") { data =>
  // received message `data` from front-end
  kernel.publish.updateHtml(s"<code>$data</code>", id)
}

TODO Send to client

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