Module: JsonRpcHandler

Extended by:
JsonRpcHandler
Included in:
JsonRpcHandler
Defined in:
lib/json_rpc_handler.rb

Defined Under Namespace

Classes: ErrorCode, Version

Constant Summary collapse

DEFAULT_ALLOWED_ID_CHARACTERS = 
/\A[a-zA-Z0-9_-]+\z/

Instance Method Summary collapse

Instance Method Details

#error_response(id:, id_validation_pattern:, error:) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 164

def error_response(id:, id_validation_pattern:, error:)
  {
    jsonrpc: Version::V2_0,
    id: valid_id?(id, id_validation_pattern) ? id : nil,
    error: error.compact,
  } unless id.nil?
end

#handle(request, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 23

def handle(request, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder)
  if request.is_a?(Array)
    return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
      code: ErrorCode::INVALID_REQUEST,
      message: "Invalid Request",
      data: "Request is an empty array",
    }) if request.empty?

    # Handle batch requests
    responses = request.map { |req| process_request(req, id_validation_pattern: id_validation_pattern, &method_finder) }.compact

    # A single item is hoisted out of the array
    return responses.first if responses.one?

    # An empty array yields nil
    responses if responses.any?
  elsif request.is_a?(Hash)
    # Handle single request
    process_request(request, id_validation_pattern: id_validation_pattern, &method_finder)
  else
    error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
      code: ErrorCode::INVALID_REQUEST,
      message: "Invalid Request",
      data: "Request must be an array or a hash",
    })
  end
end

#handle_json(request_json, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 51

def handle_json(request_json, id_validation_pattern: DEFAULT_ALLOWED_ID_CHARACTERS, &method_finder)
  begin
    request = JSON.parse(request_json, symbolize_names: true)
    response = handle(request, id_validation_pattern: id_validation_pattern, &method_finder)
  rescue JSON::ParserError
    response = error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
      code: ErrorCode::PARSE_ERROR,
      message: "Parse error",
      data: "Invalid JSON",
    })
  end

  response&.to_json
end

#handle_request_error(error, id, id_validation_pattern) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 119

def handle_request_error(error, id, id_validation_pattern)
  error_type = error.respond_to?(:error_type) ? error.error_type : nil

  code, message = case error_type
  when :invalid_request then [ErrorCode::INVALID_REQUEST, "Invalid Request"]
  when :invalid_params then [ErrorCode::INVALID_PARAMS, "Invalid params"]
  when :parse_error then [ErrorCode::PARSE_ERROR, "Parse error"]
  when :internal_error then [ErrorCode::INTERNAL_ERROR, "Internal error"]
  else [ErrorCode::INTERNAL_ERROR, "Internal error"]
  end

  error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
    code: code,
    message: message,
    data: error.message,
  })
end

#process_request(request, id_validation_pattern:, &method_finder) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 66

def process_request(request, id_validation_pattern:, &method_finder)
  id = request[:id]

  error = if !valid_version?(request[:jsonrpc])
    "JSON-RPC version must be 2.0"
  elsif !valid_id?(request[:id], id_validation_pattern)
    "Request ID must match validation pattern, or be an integer or null"
  elsif !valid_method_name?(request[:method])
    'Method name must be a string and not start with "rpc."'
  end

  return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: {
    code: ErrorCode::INVALID_REQUEST,
    message: "Invalid Request",
    data: error,
  }) if error

  method_name = request[:method]
  params = request[:params]

  unless valid_params?(params)
    return error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
      code: ErrorCode::INVALID_PARAMS,
      message: "Invalid params",
      data: "Method parameters must be an array or an object or null",
    })
  end

  begin
    method = method_finder.call(method_name)

    if method.nil?
      return error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
        code: ErrorCode::METHOD_NOT_FOUND,
        message: "Method not found",
        data: method_name,
      })
    end

    result = method.call(params)

    success_response(id: id, result: result)
  rescue MCP::Server::RequestHandlerError => e
    handle_request_error(e, id, id_validation_pattern)
  rescue StandardError => e
    error_response(id: id, id_validation_pattern: id_validation_pattern, error: {
      code: ErrorCode::INTERNAL_ERROR,
      message: "Internal error",
      data: e.message,
    })
  end
end

#success_response(id:, result:) ⇒ Object 



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# File 'lib/json_rpc_handler.rb', line 156

def success_response(id:, result:)
  {
    jsonrpc: Version::V2_0,
    id: id,
    result: result,
  } unless id.nil?
end

#valid_id?(id, pattern = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/json_rpc_handler.rb', line 141

def valid_id?(id, pattern = nil)
  return true if id.nil? || id.is_a?(Integer)
  return false unless id.is_a?(String)

  pattern ? id.match?(pattern) : true
end

#valid_method_name?(method) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/json_rpc_handler.rb', line 148

def valid_method_name?(method)
  method.is_a?(String) && !method.start_with?("rpc.")
end

#valid_params?(params) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/json_rpc_handler.rb', line 152

def valid_params?(params)
  params.nil? || params.is_a?(Array) || params.is_a?(Hash)
end

#valid_version?(version) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/json_rpc_handler.rb', line 137

def valid_version?(version)
  version == Version::V2_0
end