Class: Brute::Rack::Adapter

Inherits:
Object
  • Object
show all
Defined in:
lib/brute/rack/adapter.rb

Constant Summary collapse

PROMPT_KEYS =

Body/JSON keys we accept a prompt under, in priority order. prompt is canonical; message/input are common aliases.

%w[prompt message input].freeze

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(agent) ⇒ Adapter

Returns a new instance of Adapter.



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# File 'lib/brute/rack/adapter.rb', line 40

def initialize(agent)
  unless agent.respond_to?(:start)
    raise ArgumentError, "agent must respond to #start"
  end

  @agent = agent
end

Class Method Details

.for(agent) ⇒ Object

Convenience factory so the config.ru reads run Adapter.for(agent).



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# File 'lib/brute/rack/adapter.rb', line 36

def self.for(agent) = new(agent)

Instance Method Details

#call(env) ⇒ Object

Rack entry point. Extract the prompt, run one agent turn, render the assistant's reply back as an HTTP response. A missing prompt is a 400 (client's fault); anything the turn raises is a 500.



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# File 'lib/brute/rack/adapter.rb', line 51

def call(env)
  prompt = prompt_from(env)
  if prompt.nil? || prompt.empty?
    response_for(env, 400, "No prompt provided.")
  else
    turn = @agent.start(prompt)
    response_for(env, 200, output_of(turn))
  end
rescue => error
  response_for(env, 500, error.message)
end

#prompt_from(env) ⇒ Object

env -> prompt string. Four ways in, most explicit first:

1. a `?prompt=` query param (never touches the body),
2. a JSON body — a known key of an object, or a bare JSON string,
3. a form-encoded `prompt=` field,
4. otherwise the raw request body IS the prompt.

Returns nil when nothing usable is present.



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# File 'lib/brute/rack/adapter.rb', line 71

def prompt_from(env)
  request = ::Rack::Request.new(env)

  if (query = request.GET["prompt"]) && !query.empty?
    query
  else
    body = read_body(request)
    if body.nil? || body.strip.empty?
      nil
    else
      from_json = nil
      if json?(request.media_type)
        case data = parse_json(body)
        when ::Hash   then from_json = PROMPT_KEYS.filter_map { |key| data[key] }.first&.to_s || body
        when ::String then from_json = data
        end
      end

      if from_json
        from_json
      elsif request.form_data? && (field = ::Rack::Utils.parse_nested_query(body)["prompt"])
        field
      else
        body
      end
    end
  end
end

#response_for(env, status, output) ⇒ Object

output -> [status, headers, body]. Content-negotiated: JSON in (or an Accept: application/json) gets {"response": "..."} back; everything else gets text/plain. Errors ride the same path so a 500 body is shaped like a 200 body.



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# File 'lib/brute/rack/adapter.rb', line 104

def response_for(env, status, output)
  text = output.to_s

  if wants_json?(env)
    if status == 200
      key = :response
    else
      key = :error
    end
    [status, {"content-type" => "application/json"}, [::JSON.generate(key => text)]]
  else
    [status, {"content-type" => "text/plain; charset=utf-8"}, [text]]
  end
end