719e5e7fee
## Motivation and Context The Ruby SDK uses a 1-Server-to-many-sessions model where session-specific state (`@client`, `@logging_message_notification`) is stored on the shared `Server` instance. This causes the last client to connect to overwrite state for all sessions, and requires `session_id` to be threaded through method signatures for session-scoped notifications. The Python SDK avoids this by creating a `ServerSession` per connection that wraps a shared `Server`. Each session holds its own state and naturally scopes notifications through its own stream. ### Changes - Added `MCP::ServerSession` class holding per-session state: client info, logging configuration, and a `transport` reference for session-scoped notification delivery. - `StreamableHTTPTransport#handle_initialization` creates a `ServerSession` per `initialize` request and stores it in the session hash. - `handle_regular_request` routes requests through the session's `ServerSession` instead of the shared `Server` directly. - `Server#handle` and `Server#handle_json` accept an optional `session:` keyword (`ServerSession` instance). - `Server#init` stores client info on the session when available. - `Server#configure_logging_level` stores logging config on the session. - `ServerContext` and `Progress` accept a `notification_target:` which can be either a `ServerSession` (session-scoped) or a `Server` (broadcast). No `session_id:` parameter needed. - `ServerContext#notify_progress` and `#notify_log_message` delegate to the `notification_target` without `session_id` threading. - `StdioTransport` creates a single `ServerSession` on `open`, making the session model transparent across both transports. ### Design Decision This follows the Python SDK's "shared `Server` + per-connection `Session`" pattern. The `Server` holds configuration (tools, prompts, resources, handlers). Each `ServerSession` holds per-connection state (client info, logging level, stream writer). Notifications from `ServerSession` go only to that session's stream. ## How Has This Been Tested? All existing tests pass. All conformance tests pass. Added tests verifying: - Session-scoped log notification is sent only to the originating session. - Session-scoped progress notification is sent only to the originating session. - Each session stores its own client info independently. - Each session stores its own logging level independently. - `StdioTransport#open` creates a `ServerSession` and stores client info on it. ## Breaking Change None for end users. The public API (`Server.new`, `define_tool`,`server_context.report_progress`, `server_context.notify_log_message`, etc.) is unchanged. The following internal API changes affect only SDK internals: - `ServerContext.new` now requires `notification_target:` instead of just`progress:`. - `Progress.new` now takes `notification_target:` instead of `server:`. - `Server#handle` and `Server#handle_json` accept an optional `session:` keyword.
59 lines
1.4 KiB
Ruby
59 lines
1.4 KiB
Ruby
# frozen_string_literal: true
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require "json"
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require_relative "../../transport"
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module MCP
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class Server
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module Transports
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class StdioTransport < Transport
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STATUS_INTERRUPTED = Signal.list["INT"] + 128
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def initialize(server)
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super(server)
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@open = false
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@session = nil
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$stdin.set_encoding("UTF-8")
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$stdout.set_encoding("UTF-8")
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end
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def open
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@open = true
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@session = ServerSession.new(server: @server, transport: self)
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while @open && (line = $stdin.gets)
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response = @session.handle_json(line.strip)
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send_response(response) if response
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end
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rescue Interrupt
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warn("\nExiting...")
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exit(STATUS_INTERRUPTED)
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end
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def close
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@open = false
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end
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def send_response(message)
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json_message = message.is_a?(String) ? message : JSON.generate(message)
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$stdout.puts(json_message)
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$stdout.flush
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end
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def send_notification(method, params = nil)
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notification = {
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jsonrpc: "2.0",
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method: method,
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}
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notification[:params] = params if params
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send_response(notification)
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true
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rescue => e
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MCP.configuration.exception_reporter.call(e, { error: "Failed to send notification" })
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false
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end
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end
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end
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end
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end
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