Class: RailsAiBridge::HttpTransportApp

Inherits:
Object
  • Object
show all
Defined in:
lib/rails_ai_bridge/http_transport_app.rb

Overview

Builds the Rack endpoint used by both standalone HTTP mode and the middleware auto-mount path so request handling stays in one place.

Class Method Summary collapse

Class Method Details

.build(transport:, path:) ⇒ Proc

Returns rack-compatible app.

Parameters:

  • transport (MCP::Server::Transports::StreamableHTTPTransport) —

    transport to delegate to

  • path (String) —

    configured MCP endpoint path

Returns:

  • (Proc) —

    rack-compatible app



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# File 'lib/rails_ai_bridge/http_transport_app.rb', line 11

def build(transport:, path:)
  mcp_cfg    = RailsAiBridge.configuration.mcp
  max_reqs   = mcp_cfg.effective_http_rate_limit_max_requests
  window_sec = mcp_cfg.effective_http_rate_limit_window_seconds
  limiter    = mcp_cfg.rate_limiter || build_default_rate_limiter(max_requests: max_reqs,
                                                                  window_seconds: window_sec)
  cors_origins = Array(mcp_cfg.cors_origins).reject(&:empty?)

  lambda do |env|
    return [404, { 'Content-Type' => 'application/json' }, ['{"error":"Not found"}']] unless [path, "#{path}/"].include?(env['PATH_INFO'])

    request = Rack::Request.new(env)
    cors_headers = build_cors_headers(request.get_header('HTTP_ORIGIN'), cors_origins)

    return [204, cors_headers, ['']] if request.request_method == 'OPTIONS' && cors_headers

    if mcp_cfg.require_http_auth && !Mcp::Authenticator.any_configured?
      Mcp::HttpStructuredLog.emit(request: request, event: :unauthorized, http_status: 401)
      return Mcp::Authenticator.unauthorized_rack_response
    end

    auth_result = Mcp::Authenticator.call(request)
    unless auth_result.success?
      Mcp::HttpStructuredLog.emit(request: request, event: :unauthorized, http_status: 401)
      return Mcp::Authenticator.unauthorized_rack_response
    end

    authorize = RailsAiBridge.configuration.mcp.authorize
    if authorize
      begin
        authorized = authorize.call(auth_result.context, request)
      rescue StandardError => error
        Rails.logger.error("rails_ai_bridge: authorize lambda raised #{error.class}: #{error.message}") if defined?(Rails) && Rails.logger
        Mcp::HttpStructuredLog.emit(request: request, event: :forbidden, http_status: 403)
        return [403, { 'Content-Type' => 'application/json' }, ['{"error":"Forbidden"}']]
      end

      unless authorized
        Rails.logger.warn("rails_ai_bridge: authorize lambda denied access for #{request.ip} at #{request.path}") if defined?(Rails) && Rails.logger
        Mcp::HttpStructuredLog.emit(request: request, event: :forbidden, http_status: 403)
        return [403, { 'Content-Type' => 'application/json' }, ['{"error":"Forbidden"}']]
      end
    end

    if limiter && !rate_limiter_allow?(limiter, request)
      Instrumentation.instrument('rate_limit.hit', ip: request.ip, path: request.path)
      Mcp::HttpStructuredLog.emit(request: request, event: :rate_limited, http_status: 429)
      return [429, { 'Content-Type' => 'application/json', 'Retry-After' => window_sec.to_s },
              ['{"error":"Too many requests"}']]
    end

    response = transport.handle_request(request)
    Mcp::HttpStructuredLog.emit(request: request, event: :handled, http_status: response.first)
    response[1].merge!(cors_headers) if cors_headers
    response
  end
end