Class: Datastar::ServerSentEventGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/datastar/server_sent_event_generator.rb

Constant Summary collapse

MSG_END = 
"\n"
DEFAULT_SSE_RETRY_DURATION = 
1000
DEFAULT_ELEMENTS_USE_VIEW_TRANSITIONS = 
false
DEFAULT_ELEMENTS_VIEW_TRANSITION_SELECTOR = 
''
DEFAULT_ELEMENTS_NAMESPACE = 
'html'
DEFAULT_PATCH_SIGNALS_ONLY_IF_MISSING = 
false
SELECTOR_DATALINE_LITERAL = 
'selector'
MODE_DATALINE_LITERAL = 
'mode'
ELEMENTS_DATALINE_LITERAL = 
'elements'
USE_VIEW_TRANSITION_DATALINE_LITERAL = 
'useViewTransition'
VIEW_TRANSITION_SELECTOR_DATALINE_LITERAL = 
'viewTransitionSelector'
NAMESPACE_DATALINE_LITERAL = 
'namespace'
SIGNALS_DATALINE_LITERAL = 
'signals'
ONLY_IF_MISSING_DATALINE_LITERAL = 
'onlyIfMissing'
SSE_OPTION_MAPPING = 
{
  'eventId' => 'id',
  'retryDuration' => 'retry',
  'id' => 'id',
  'retry' => 'retry',
}.freeze
DEFAULT_ELEMENT_PATCH_MODE = 
ElementPatchMode::OUTER
OPTION_DEFAULTS = 
{
  'retry' => DEFAULT_SSE_RETRY_DURATION,
  MODE_DATALINE_LITERAL => DEFAULT_ELEMENT_PATCH_MODE,
  USE_VIEW_TRANSITION_DATALINE_LITERAL => DEFAULT_ELEMENTS_USE_VIEW_TRANSITIONS,
  VIEW_TRANSITION_SELECTOR_DATALINE_LITERAL => DEFAULT_ELEMENTS_VIEW_TRANSITION_SELECTOR,
  NAMESPACE_DATALINE_LITERAL => DEFAULT_ELEMENTS_NAMESPACE,
  ONLY_IF_MISSING_DATALINE_LITERAL => DEFAULT_PATCH_SIGNALS_ONLY_IF_MISSING,
}.freeze
SIGNAL_SEPARATOR = 
'.'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(stream, signals:, view_context: nil) ⇒ ServerSentEventGenerator

Returns a new instance of ServerSentEventGenerator.

Parameters:

  • stream (IO, Queue) —

    The IO stream or Queue to write to

  • signals (Hash) —

    a customizable set of options

  • view_context (Hash) (defaults to: nil) —

    a customizable set of options

Options Hash (signals:):

  • A (Hash) —

    hash of signals (params)

Options Hash (view_context:):

  • The (Object) —

    view context for rendering elements, if applicable.



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# File 'lib/datastar/server_sent_event_generator.rb', line 75

def initialize(stream, signals:, view_context: nil)
  @stream = stream
  @signals = signals
  @view_context = view_context
end

Instance Attribute Details

#signals ⇒ Object (readonly)

Returns the value of attribute signals.



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# File 'lib/datastar/server_sent_event_generator.rb', line 70

def signals
  @signals
end

Instance Method Details

#check_connection! ⇒ Object

Sometimes we’ll want to run periodic checks to ensure the connection is still alive ie. the browser hasn’t disconnected For example when idle listening on an event bus.



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# File 'lib/datastar/server_sent_event_generator.rb', line 84

def check_connection!
  @stream << MSG_END
end

#execute_script(script, options = BLANK_OPTIONS) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 138

def execute_script(script, options = BLANK_OPTIONS)
  options = camelize_keys(options)
  auto_remove = options.key?('autoRemove') ? options.delete('autoRemove') : true
  attributes = options.delete('attributes') || BLANK_OPTIONS
  script_tag = +"<script"
  attributes.each do |k, v|
    script_tag << %( #{camelize(k)}="#{v}")
  end
  script_tag << %( data-effect="el.remove()") if auto_remove
  script_tag << ">#{script}</script>"

  options[SELECTOR_DATALINE_LITERAL] = 'body'
  options[MODE_DATALINE_LITERAL] = ElementPatchMode::APPEND

  patch_elements(script_tag, options)
end

#patch_elements(elements, options = BLANK_OPTIONS) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 88

def patch_elements(elements, options = BLANK_OPTIONS)
  elements = Array(elements).compact
  rendered_elements = elements.map do |element|
    render_element(element)
  end

  element_lines = rendered_elements.flat_map do |el|
    el.to_s.split("\n")
  end

  buffer = +"event: datastar-patch-elements\n"
  build_options(options, buffer)
  element_lines.each { |line| buffer << "data: #{ELEMENTS_DATALINE_LITERAL} #{line}\n" }

  write(buffer)
end

#patch_signals(signals, options = BLANK_OPTIONS) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 115

def patch_signals(signals, options = BLANK_OPTIONS)
  buffer = +"event: datastar-patch-signals\n"
  build_options(options, buffer)
  case signals
  when Hash
    signals = JSON.dump(signals)
    buffer << "data: signals #{signals}\n"
  when String
    multi_data_lines(signals, buffer, SIGNALS_DATALINE_LITERAL)
  end
  write(buffer)
end

#redirect(url) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 155

def redirect(url)
  execute_script %(setTimeout(() => { window.location = '#{url}' }))
end

#remove_elements(selector, options = BLANK_OPTIONS) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 105

def remove_elements(selector, options = BLANK_OPTIONS)
  patch_elements(
    nil, 
    options.merge(
      MODE_DATALINE_LITERAL => ElementPatchMode::REMOVE,
      selector:
    )
  )
end

#remove_signals(paths, options = BLANK_OPTIONS) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 128

def remove_signals(paths, options = BLANK_OPTIONS)
  paths = [paths].flatten
  signals = paths.each.with_object({}) do |path, acc|
    parts = path.split(SIGNAL_SEPARATOR)
    set_nested_value(acc, parts, nil)
  end

  patch_signals(signals, options)
end

#write(buffer) ⇒ Object 



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# File 'lib/datastar/server_sent_event_generator.rb', line 159

def write(buffer)
  buffer << MSG_END
  @stream << buffer
end