Programmatic blocks

The demo website has two blocks defined by modules: one that renders a random quote and one that renders the weather forecast of the next hour for the origin location of a trip.

Blocks are defined as plugins and must follow a set of rules to be available on the frontend, but in the end, a block will return a render array exactly as a controller does.

Both blocks are already available in the alps_quote and alps_weather modules. The weather forecast one, for example, returns this render array:

$build['content'] = [
  '#theme' => 'alps_weather_forecast_single',
  '#forecast' => $forecast['list'][0],
  '#city' => $city,
  '#units' => $this->config
    ->get('alps_weather.settings')->get('units'),
  '#cache' => [
    'max-age' => 10800...