Class: Skein::Handler

Inherits:
Object
  • Object
show all
Defined in:
lib/skein/handler.rb

Direct Known Subclasses

Async, Threaded

Defined Under Namespace

Classes: Async, Threaded

Constant Summary collapse

RPC_BASE =

Constants ============================================================

{
  jsonrpc: '2.0'
}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(target, context = nil) ⇒ Handler

Instance Methods =====================================================



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# File 'lib/skein/handler.rb', line 25

def initialize(target, context = nil)
  @target = target
  @context = context || target.context
end

Instance Attribute Details

#context ⇒ Object (readonly)

Properties ===========================================================



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# File 'lib/skein/handler.rb', line 4

def context
  @context
end

Class Method Details

.for(target) ⇒ Object

Class Methods ========================================================



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# File 'lib/skein/handler.rb', line 14

def self.for(target)
  case (target.respond_to?(:async?) and target.async?)
  when true
    Skein::Handler::Async.new(target)
  else
    Skein::Handler::Threaded.new(target)
  end
end

Instance Method Details

#handle(message_json, metrics, state) ⇒ Object 



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# File 'lib/skein/handler.rb', line 34

def handle(message_json, metrics, state)
  state[:started] = Time.now
  state[:finished] = nil
  state[:thread] = Thread.current
  state[:method] = :handle

  request =
    begin
      JSON.load(message_json)

    rescue Object => e
      @context and @context.exception!(e, message_json)

      metrics[:failed] += 1
      metrics[:errors][:parsing] += 1
      metrics[:time] += state[:finished] - state[:started]
      state[:method] = nil

      return yield(rpc_json(
        error: {
          code: -32700,
          message: 'Parse error'
        },
        id: nil
      ))
    end

  case (request)
  when Hash
    # Acceptable
  else
    metrics[:failed] += 1
    metrics[:errors][:non_jsonrpc] += 1
    metrics[:time] += state[:finished] - state[:started]
    state[:method] = nil

    return yield(json_rpc(
      error: {
        code: -32600,
        message: 'Request does not conform to the JSON-RPC format.'
      },
      id: nil
    ))
  end

  request['params'] =
    case (params = request['params'])
    when Array
      params
    when nil
      request.key?('params') ? [ nil ] : [ ]
    else
      [ request['params'] ]
    end

  unless (request['method'] and request['method'].is_a?(String) and request['method'].match(/\S/))
    metrics[:failed] += 1
    metrics[:errors][:no_method_property] += 1
    metrics[:time] += state[:finished] - state[:started]
    state[:method] = nil

    return yield(json_rpc(
      error: {
        code: -32600,
        message: 'Request does not conform to the JSON-RPC format, missing valid method.'
      },
      id: request['id']
    ))
  end

  begin
    method_name = request['method'].to_sym
    @target.before_execution(method_name)
    state[:method] = method_name

    delegate(method_name, *request['params']) do |result|
      @target.after_execution(method_name)
      state[:finished] = Time.now
      metrics[:time] += state[:finished] - state[:started]
      state[:method] = nil

      case (result)
      when Exception
        metrics[:failed] += 1
        metrics[:errors][:exception] += 1

        yield(json_rpc(
          error: {
            code: -32603,
            message: result.to_s
          },
          id: request['id']
        ))
      else
        metrics[:succeeded] += 1

        yield(json_rpc(
          result: result,
          id: request['id']
        ))
      end
    end

  rescue ArgumentError => e
    # REFACTOR: Make these exception catchers only trap immediate errors,
    #           not those that occur within the delegated code.
    @context and @context.exception!(e, message_json)

    metrics[:failed] += 1
    metrics[:errors][:invalid_arguments] += 1
    state[:finished] = Time.now
    metrics[:time] += state[:finished] - state[:started]
    state[:method] = nil

    yield(json_rpc(
      error: {
        code: -32602,
        message: 'Invalid params',
        data: {
          method: request['method'],
          params: request['params'],
          message: e.to_s
        }
      },
      id: request['id']
    ))
  rescue NoMethodError => e
    @context and @context.exception!(e, message_json)

    metrics[:failed] += 1
    metrics[:errors][:invalid_arguments] += 1
    state[:finished] = Time.now
    metrics[:time] += state[:finished] - state[:started]
    state[:method] = nil

    yield(json_rpc(
      error: {
        code: -32601,
        message: e.to_s,
        data: {
          method: request['method']
        }
      },
      id: request['id']
    ))
  rescue Object => e
    @context and @context.exception!(e, message_json)

    metrics[:failed] += 1
    metrics[:errors][:exception] += 1
    state[:finished] = Time.now
    metrics[:time] += state[:finished] - state[:started]
    state[:method] = nil

    yield(json_rpc(
      error: {
        code: -32063, 
        message: '[%s] %s' % [ e.class, e ]
      },
      id: request['id']
    ))
  end
end

#json_rpc(contents) ⇒ Object 



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# File 'lib/skein/handler.rb', line 30

def json_rpc(contents)
  JSON.dump(RPC_BASE.merge(contents))
end