Class: MCP::Rails::ServerGenerator::ServerWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/mcp/rails/server_generator/server_writer.rb

Class Method Summary collapse

Class Method Details

.generate_parameter(param, indent_level = 1) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 54

def self.generate_parameter(param, indent_level = 1)
  indent = "  " * indent_level
  name = param[:name].to_sym
  required = param[:required] ? ", required: true" : ""
  description = param[:description] ? ", description: \"#{param[:description]}\"" : ""

  if param[:type] == :array
    if param[:item_type]
      # Scalar array: argument :name, Array, items: Type
      type_str = "Array, items: #{type_to_class(param[:item_type])}"
      "#{indent}argument :#{name}, #{type_str}#{required}#{description}"
    elsif param[:nested]
      # Array of objects: argument :name, Array do ... end
      nested_params = param[:nested].map { |np| generate_parameter(np, indent_level + 1) }.join("\n")
      "#{indent}argument :#{name}, Array#{required}#{description} do\n#{nested_params}\n#{indent}end"
    else
      raise "Array parameter must have either item_type or nested parameters"
    end
  elsif param[:type] == :object && param[:nested]
    # Object: argument :name do ... end
    nested_params = param[:nested].map { |np| generate_parameter(np, indent_level + 1) }.join("\n")
    "#{indent}argument :#{name}#{required}#{description} do\n#{nested_params}\n#{indent}end"
  else
    # Scalar type: argument :name, Type
    type_str = type_to_class(param[:type])
    "#{indent}argument :#{name}, #{type_str}#{required}#{description}"
  end
end

.helper_methods(base_uri, bypass_csrf_key) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 113

def self.helper_methods(base_uri, bypass_csrf_key)
  return test_helper_methods(base_uri, bypass_csrf_key) if ::Rails.env.test?
  <<~RUBY
    def transform_args(args)
      if args.is_a?(Hash)
        args.transform_keys { |key| key.to_s.gsub(/([a-z])([A-Z])/, '\\1_\\2').gsub(/([A-Z])([A-Z][a-z])/, '\\1_\\2').downcase }
          .transform_values { |value| transform_args(value) }
      else
        args # Return non-hash values (e.g., strings, integers) unchanged
      end
    end

    def parse_response(response)
      response_body = JSON.parse(response.body)
      case response_body
      when Hash
        if response_body["status"] == "error"
          raise "From Rails Server: \#{response_body["message"]}"
        else
          response_body.dig("data").to_json
        end
      else
        raise "None MCP response from Rails Server"
      end
    rescue => e
      raise "Parsing JSON failed: \#{e.message}"
    end

    def get_resource(uri, arguments = {})
      response = HTTParty.get("#{base_uri}\#{uri}", query: transform_args(arguments), headers: { "Accept" => "application/vnd.mcp+json, application/json" })
      parse_response(response)
    end

    def post_resource(uri, payload = {})
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      response = HTTParty.post("#{base_uri}\#{uri}", body: transform_args(payload), headers: headers)
      parse_response(response)
    end

    def patch_resource(uri, payload = {})
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      response = HTTParty.patch("#{base_uri}\#{uri}", body: transform_args(payload), headers: headers)
      parse_response(response)
    end

    def delete_resource(uri, payload = {})
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      response = HTTParty.delete("#{base_uri}\#{uri}", body: transform_args(payload), headers: headers)
      parse_response(response)
    end
  RUBY
end

.route_block(route, config) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 169

def self.route_block(route, config)
  uri = route[:path]
  route[:url_parameters].each do |url_parameter|
    uri = uri.gsub(":#{url_parameter[:name]}", "\#{args[:#{url_parameter[:name]}]}")
  end

  env_vars = config.env_vars.map do |var|
    "args[:#{var.downcase}] = ENV['#{var}']"
  end.join("\n")

  method = route[:method].to_s.downcase
  helper_method = "#{method}_resource"

  <<~RUBY
    call do |args|
      #{env_vars}
      #{helper_method}("#{uri}", args)
    end
  RUBY
end

.ruby_invocation ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 83

def self.ruby_invocation
  <<~RUBY
    #!/usr/bin/env ruby

    # Find the nearest Gemfile by walking up the directory tree
    def find_nearest_gemfile(start_dir)
      current_dir = File.expand_path(start_dir)
      loop do
        gemfile = File.join(current_dir, "Gemfile")
        return gemfile if File.exist?(gemfile)
        parent_dir = File.dirname(current_dir)
        break if parent_dir == current_dir # Reached root (e.g., "/")
        current_dir = parent_dir
      end
      nil # No Gemfile found
    end

    # If not already running under bundle exec, re-execute with the nearest Gemfile
    unless ENV["BUNDLE_GEMFILE"] # Check if already running under Bundler
      gemfile = find_nearest_gemfile(__dir__) # __dir__ is the script's directory
      if gemfile
        ENV["BUNDLE_GEMFILE"] = gemfile
        exec("bundle", "exec", "ruby", __FILE__, *ARGV) # Re-run with bundle exec
      else
        warn "Warning: No Gemfile found in any parent directory."
      end
    end
  RUBY
end

.test_helper_methods(base_uri, bypass_csrf_key) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 190

def self.test_helper_methods(base_uri, bypass_csrf_key)
  <<~RUBY
    def parse_response(test_context)
      # Would be url: #{base_uri}
      parsed_body = JSON.parse(test_context.response.body)
      case parsed_body
      when Hash
        if parsed_body["status"] == "error"
          raise "From Rails Server: \#{parsed_body["message"]}"
        else
          parsed_body.dig("data")
        end
      else
        raise "None MCP response from Rails Server"
      end
    rescue => e
      raise "Parsing JSON failed: \#{e.message}"
    end

    def get_resource(uri, arguments = {})
      test_context = arguments.delete(:test_context)
      test_context.get uri, params: arguments, headers: { "Accept" => "application/vnd.mcp+json, application/json" }, as: :mcp
      parse_response(test_context)
    end

    def post_resource(uri, payload = {}, headers = {})
      test_context = payload.delete(:test_context)
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      test_context.post uri, params: payload, headers: headers, as: :mcp
      parse_response(test_context)
    end

    def patch_resource(uri, payload = {})
      test_context = payload.delete(:test_context)
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      test_context.patch uri, params: payload.merge(headers: headers), as: :mcp
      parse_response(test_context)
    end

    def delete_resource(uri, payload = {})
      test_context = payload.delete(:test_context)
      headers = { "Accept" => "application/vnd.mcp+json, application/json" }
      headers["X-Bypass-CSRF"] = "#{bypass_csrf_key}"
      test_context.delete uri, params: payload.merge(headers: headers), as: :mcp
      parse_response(test_context)
    end
  RUBY
end

.type_to_class(type) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 43

def self.type_to_class(type)
  case type
  when :string then "String"
  when :integer then "Integer"
  when :number then "Float"
  when :boolean then "TrueClass"
  when :array then "Array"
  else "String"  # Default to String
  end
end

.write_server(routes_data, config, base_url, bypass_csrf_key, engine = nil) ⇒ Object 



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# File 'lib/mcp/rails/server_generator/server_writer.rb', line 4

def self.write_server(routes_data, config, base_url, bypass_csrf_key, engine = nil)
  # Get engine-specific configuration if available
  config = config.for_engine(engine)

  file_name = engine ? "#{config.server_name}_server.rb" : "server.rb"
  file_path = File.join(config.output_directory.to_s, file_name)
  FileUtils.mkdir_p(File.dirname(file_path))

  File.open(file_path, "w") do |file|
    file.puts ruby_invocation
    file.puts
    file.puts %(require "mcp")
    file.puts %(require "httparty")
    file.puts
    file.puts helper_methods(base_url, bypass_csrf_key)
    file.puts

    file.puts %(name "#{config.server_name}")
    file.puts %(version "#{config.server_version}")

    routes_data.each do |route|
      file.puts %(tool "#{route[:tool_name].underscore}" do)
      file.puts "  description \"#{route[:description].sub(/\//, ' ')}\""
      route[:accepted_parameters].each do |param|
        file.puts generate_parameter(param)
      end
      file.puts route_block(route, config).lines.map { |line| "  #{line}" }.join
      file.puts "end"
      file.puts
    end
  end

  current_mode = File.stat(file_path).mode
  new_mode = current_mode | 0111  # Add execute (u+x, g+x, o+x)
  File.chmod(new_mode, file_path)

  file_path
end