README.md

As of Nushell 0.102.0 nu's generate command now supports stateful aggregation and downstream of streaming input. This means a plugin for things like from sse is no longer required. You can achieve the same result with a custom command similar to:

export def "from sse" [] {
  lines | generate {|line pending = {data: []}|

    match ($line | split row -n 2 ":" | each { str trim }) {
      [$prefix $content] if $prefix == "id" => {
        return {next: ($pending | upsert id $content)}
      }

      [$prefix $content] if $prefix == "event" => {
        return {next: ($pending | upsert event $content)}
      }

      [$prefix $content] if $prefix == "data" => {
        return {next: ($pending | update data { append $content })}
      }

      [$empty] if $empty == "" => {
        if ($pending == {data: []}) {
          return {next: $pending}
        }
        return {next: {data: []} out: ($pending | update data { str join "\n" })}
      }

      _ => { error make {msg: $"unexpected: ($line)"} }
    }
  }
}

nu streaming plugin: nu_plugin_from_sse

This plugin was forked from the nu_plugin_example.

Install with Cargo

From within nushell:

cargo install --locked nu_plugin_from_sse
plugin add ~/.cargo/bin/nu_plugin_from_sse
# and then restart nu or use plugin add to activate

Usage

nu_plugin_from_sse provides one command:

from sse

This command transforms HTTP SSE (Server-Sent Events) into structured records with the shape:

{
  id: string,    // Unique identifier for the SSE event
  event: string, // Type of event
  data: string   // Data payload of the event
}

known issue: nu table buffering #12129

If your SSE endpoint dispatches initial events upon connection, then pauses—awaiting rare updates—you won't see any output until the first new update after connecting. This behavior is due to nu's table buffering mechanism, where a duration timeout is factored in only during active input processing.

An easy workaround for this issue is to pipe to each.

example

Copy this text to your clipboard:

event: creatureAlert
id: 1
data: {"id":"uni123","type":"Unicorn","lat":45.4235,"lon":-75.6979,"urgency":"high","desc":"Injured near Crystal River."}

Use bp to pipe it:

bp | from sse | update data { from json }

live example

http get https://ndyg.cross.stream/projects/enchanted-animal-rescue/rescue-feed |
    from sse |
    update data { from json }