mcp::transport::Transport< Role > Class Template Reference

Minimal message-level transport contract shared by MCP roles. More...

#include <transport.hpp>

Inheritance diagram for mcp::transport::Transport< Role >:

Public Types
using	TxMessage = typename MessageTraits< Role >::TxMessage
using	RxMessage = typename MessageTraits< Role >::RxMessage

Public Member Functions
virtual std::string_view	name () const noexcept=0
	Human-readable transport name for diagnostics.
virtual protocol::Json	diagnostics () const
	Structured implementation diagnostics.
virtual core::Result< core::Unit >	send (TxMessage message)=0
	Sends one JSON-RPC message to the peer.
virtual core::Result< std::optional< RxMessage > >	receive ()=0
	Receives the next JSON-RPC message from the peer.
virtual core::Result< core::Unit >	close ()=0
	Closes the transport and unblocks receive() where possible.
virtual void	wait_until_ready ()
	Blocks until the transport is ready to process messages.

Detailed Description

template<class Role>
class mcp::transport::Transport< Role >

Minimal message-level transport contract shared by MCP roles.

This contract is intentionally limited to one outbound operation, one inbound operation, explicit close, and diagnostics. Higher-level session, retry, policy, and gateway behavior must live above this interface.

Implementations must document whether send() may be called concurrently. receive() is sequential: callers must not call receive() concurrently on the same transport unless a concrete implementation explicitly says otherwise. A successful receive() returning std::nullopt means the inbound stream ended cleanly or close() has completed. close() is best-effort, should be idempotent, and should unblock a blocked receive() where the underlying platform transport can do so.

Member Function Documentation

close()

template<class Role >

virtual core::Result< core::Unit > mcp::transport::Transport< Role >::close ( )

pure virtual

Closes the transport and unblocks receive() where possible.

Implemented in mcp::client::TransportContractAdapter, mcp::server::TransportContractAdapter, mcp::transport::FunctionTransport< Role >, mcp::transport::JsonLineTransport< Role >, mcp::transport::QueueTransport< Role >, mcp::transport::StreamableHttpClientTransport, mcp::transport::StreamableHttpServerTransport, mcp::transport::ProcessStdioClientTransport, mcp::transport::StdioTransport< Role >, mcp::transport::WebSocketClientTransport, and mcp::transport::WebSocketServerTransport.

diagnostics()

template<class Role >

virtual protocol::Json mcp::transport::Transport< Role >::diagnostics ( ) const

inlinevirtual

Structured implementation diagnostics.

The default keeps the core contract narrow. Transports with useful state may return keys such as "name", "closed", "inflight", or backend-specific counters. Diagnostics are not part of the wire protocol.

Reimplemented in mcp::transport::FunctionTransport< Role >, mcp::transport::JsonLineTransport< Role >, mcp::transport::QueueTransport< Role >, mcp::transport::StreamableHttpClientTransport, mcp::transport::StreamableHttpServerTransport, mcp::transport::ProcessStdioClientTransport, mcp::transport::StdioTransport< Role >, mcp::transport::WebSocketClientTransport, and mcp::transport::WebSocketServerTransport.

name()

template<class Role >

virtual std::string_view mcp::transport::Transport< Role >::name ( ) const

pure virtualnoexcept

Human-readable transport name for diagnostics.

Implemented in mcp::client::TransportContractAdapter, mcp::server::TransportContractAdapter, mcp::transport::FunctionTransport< Role >, mcp::transport::JsonLineTransport< Role >, mcp::transport::QueueTransport< Role >, mcp::transport::StreamableHttpClientTransport, mcp::transport::StreamableHttpServerTransport, mcp::transport::ProcessStdioClientTransport, mcp::transport::StdioTransport< Role >, mcp::transport::WebSocketClientTransport, and mcp::transport::WebSocketServerTransport.

receive()

template<class Role >

virtual core::Result< std::optional< RxMessage > > mcp::transport::Transport< Role >::receive ( )

pure virtual

Receives the next JSON-RPC message from the peer.

receive() is the sequential inbound side. A successful std::nullopt return is an orderly end-of-stream signal, not a parse or transport error.

Implemented in mcp::client::TransportContractAdapter, mcp::server::TransportContractAdapter, mcp::transport::FunctionTransport< Role >, mcp::transport::JsonLineTransport< Role >, mcp::transport::QueueTransport< Role >, mcp::transport::StreamableHttpClientTransport, mcp::transport::StreamableHttpServerTransport, mcp::transport::ProcessStdioClientTransport, mcp::transport::StdioTransport< Role >, mcp::transport::WebSocketClientTransport, and mcp::transport::WebSocketServerTransport.

send()

template<class Role >

virtual core::Result< core::Unit > mcp::transport::Transport< Role >::send ( TxMessage  message )

pure virtual

Sends one JSON-RPC message to the peer.

Concurrency safety is implementation-specific and must be documented by the concrete transport.

Implemented in mcp::transport::FunctionTransport< Role >, mcp::transport::JsonLineTransport< Role >, mcp::transport::QueueTransport< Role >, mcp::transport::StreamableHttpClientTransport, mcp::transport::StreamableHttpServerTransport, mcp::transport::ProcessStdioClientTransport, mcp::transport::StdioTransport< Role >, mcp::transport::WebSocketClientTransport, and mcp::transport::WebSocketServerTransport.

wait_until_ready()

template<class Role >

virtual void mcp::transport::Transport< Role >::wait_until_ready ( )

inlinevirtual

Blocks until the transport is ready to process messages.

The default is a no-op. Transports that need asynchronous startup (e.g. binding a socket) override this to block until the underlying resource is available.

Reimplemented in mcp::transport::StreamableHttpServerTransport, and mcp::transport::WebSocketServerTransport.

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The documentation for this class was generated from the following file:

• sdk/transport/include/cxxmcp/transport/transport.hpp