Module: FastMcp

Defined in:
lib/fast_mcp.rb,
lib/fast_mcp.rb,
lib/mcp/tool.rb,
lib/mcp/logger.rb,
lib/mcp/server.rb,
lib/mcp/railtie.rb,
lib/mcp/version.rb,
lib/mcp/resource.rb,
lib/mcp/server_filtering.rb,
lib/mcp/transports/base_transport.rb,
lib/mcp/transports/rack_transport.rb,
lib/mcp/transports/stdio_transport.rb,
lib/mcp/transports/authenticated_rack_transport.rb,
lib/generators/fast_mcp/install/install_generator.rb

Overview

This class is not used yet.

Defined Under Namespace

Modules: Generators, ServerFiltering, Transports Classes: Logger, Railtie, Resource, Server, Tool

Constant Summary collapse

VERSION = 
'1.6.0'

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.server ⇒ Object

Returns the value of attribute server.



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# File 'lib/fast_mcp.rb', line 9

def server
  @server
end

Class Method Details

.authenticated_rack_middleware(app, options = {}) {|server| ... } ⇒ #call

Create a Rack middleware for the MCP server with authentication

Parameters:

  • app (#call) —

    The Rack application

  • options (Hash) (defaults to: {}) —

    Options for the middleware

Options Hash (options):

  • :name (String) —

    The name of the server

  • :version (String) —

    The version of the server

  • :auth_token (String) —

    The authentication token

  • :allowed_origins (Array<String,Regexp>) —

    List of allowed origins for DNS rebinding protection

Yields:

  • (server) —

    A block to configure the server

Yield Parameters:

Returns:

  • (#call) —

    The Rack middleware



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# File 'lib/fast_mcp.rb', line 71

def self.authenticated_rack_middleware(app, options = {})
  options[:transport] ||= FastMcp::Transports::AuthenticatedRackTransport
  rack_middleware(app, options)
end

.default_rails_allowed_origins(rail_app) ⇒ Object 



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# File 'lib/fast_mcp.rb', line 159

def self.default_rails_allowed_origins(rail_app)
  hosts = rail_app.config.hosts

  hosts.map do |host|
    if host.is_a?(String) && host.start_with?('.')
      # Convert .domain to domain and *.domain
      host_without_dot = host[1..]
      [host_without_dot, Regexp.new(".*\.#{host_without_dot}")] # rubocop:disable Style/RedundantStringEscape
    else
      host
    end
  end.flatten.compact
end

.mount_in_rails(app, options = {}) {|server| ... } ⇒ #call

Mount the MCP middleware in a Rails application

Parameters:

  • app (Rails::Application) —

    The Rails application

  • options (Hash) (defaults to: {}) —

    Options for the middleware

Options Hash (options):

  • :name (String) —

    The name of the server

  • :version (String) —

    The version of the server

  • :path_prefix (String) —

    The path prefix for the MCP endpoints

  • :messages_route (String) —

    The route for the messages endpoint

  • :sse_route (String) —

    The route for the SSE endpoint

  • :logger (Logger) —

    The logger to use

  • :authenticate (Boolean) —

    Whether to use authentication

  • :auth_token (String) —

    The authentication token

  • :allowed_origins (Array<String,Regexp>) —

    List of allowed origins for DNS rebinding protection

Yields:

  • (server) —

    A block to configure the server

Yield Parameters:

Returns:

  • (#call) —

    The Rack middleware



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# File 'lib/fast_mcp.rb', line 123

def self.mount_in_rails(app, options = {})
  # Default options
  name = options.delete(:name) || app.class.module_parent_name.underscore.dasherize
  version = options.delete(:version) || '1.0.0'
  logger = options[:logger] || Rails.logger
  path_prefix = options.delete(:path_prefix) || '/mcp'
  messages_route = options.delete(:messages_route) || 'messages'
  sse_route = options.delete(:sse_route) || 'sse'
  authenticate = options.delete(:authenticate) || false
  allowed_origins = options[:allowed_origins] || default_rails_allowed_origins(app)
  allowed_ips = options[:allowed_ips] || FastMcp::Transports::RackTransport::DEFAULT_ALLOWED_IPS

  options[:localhost_only] = Rails.env.local? if options[:localhost_only].nil?
  options[:allowed_ips] = allowed_ips
  options[:logger] = logger
  options[:allowed_origins] = allowed_origins

  # Create or get the server
  self.server = FastMcp::Server.new(name: name, version: version, logger: logger)
  yield self.server if block_given?

  # Choose the right middleware based on authentication
  self.server.transport_klass = if authenticate
                                  FastMcp::Transports::AuthenticatedRackTransport
                                else
                                  FastMcp::Transports::RackTransport
                                end

  # Insert the middleware in the Rails middleware stack
  app.middleware.use(
    self.server.transport_klass,
    self.server,
    options.merge(path_prefix: path_prefix, messages_route: messages_route, sse_route: sse_route)
  )
end

.notify_resource_updated(uri) ⇒ Object

Notify the server that a resource has been updated

Parameters:

  • uri (String) —

    The URI of the resource



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# File 'lib/fast_mcp.rb', line 175

def self.notify_resource_updated(uri)
  self.server.notify_resource_updated(uri)
end

.rack_middleware(app, options = {}) {|server| ... } ⇒ #call

Create a Rack middleware for the MCP server

Parameters:

  • app (#call) —

    The Rack application

  • options (Hash) (defaults to: {}) —

    Options for the middleware

Options Hash (options):

  • :name (String) —

    The name of the server

  • :version (String) —

    The version of the server

  • :path_prefix (String) —

    The path prefix for the MCP endpoints

  • :messages_route (String) —

    The route for the messages endpoint

  • :sse_route (String) —

    The route for the SSE endpoint

  • :logger (Logger) —

    The logger to use

  • :transport (Class) —

    The transport class to use

  • :allowed_origins (Array<String,Regexp>) —

    List of allowed origins for DNS rebinding protection

Yields:

  • (server) —

    A block to configure the server

Yield Parameters:

Returns:

  • (#call) —

    The Rack middleware



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# File 'lib/fast_mcp.rb', line 44

def self.rack_middleware(app, options = {})
  name = options.delete(:name) || 'mcp-server'
  version = options.delete(:version) || '1.0.0'
  logger = options.delete(:logger) || Logger.new

  server = FastMcp::Server.new(name: name, version: version, logger: logger)
  yield server if block_given?

  # Store the server in the Sinatra settings if available
  app.settings.set(:mcp_server, server) if app.respond_to?(:settings) && app.settings.respond_to?(:mcp_server=)

  # Store the server in the FastMcp module
  self.server = server

  server.start_rack(app, options)
end

.register_resource(resource) ⇒ FastMcp::Resource

Register a resource with the MCP server

Parameters:

Returns:



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# File 'lib/fast_mcp.rb', line 95

def self.register_resource(resource)
  self.server ||= FastMcp::Server.new(name: 'mcp-server', version: '1.0.0')
  self.server.register_resource(resource)
end

.register_resources(*resources) ⇒ Array<FastMcp::Resource>

Register multiple resources at once

Parameters:

Returns:



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# File 'lib/fast_mcp.rb', line 103

def self.register_resources(*resources)
  self.server ||= FastMcp::Server.new(name: 'mcp-server', version: '1.0.0')
  self.server.register_resources(*resources)
end

.register_tool(tool) ⇒ FastMcp::Tool

Register a tool with the MCP server

Parameters:

Returns:



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# File 'lib/fast_mcp.rb', line 79

def self.register_tool(tool)
  self.server ||= FastMcp::Server.new(name: 'mcp-server', version: '1.0.0')
  self.server.register_tool(tool)
end

.register_tools(*tools) ⇒ Array<FastMcp::Tool>

Register multiple tools at once

Parameters:

Returns:



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# File 'lib/fast_mcp.rb', line 87

def self.register_tools(*tools)
  self.server ||= FastMcp::Server.new(name: 'mcp-server', version: '1.0.0')
  self.server.register_tools(*tools)
end