Struct StdioTransport

pub struct StdioTransport { /* private fields */ }

Implements a standard I/O transport for MCP communication.

This module provides the StdioTransport struct, which serves as a transport layer for the Model Context Protocol (MCP) using standard input/output (stdio). It supports both client-side and server-side communication by optionally launching a subprocess or using the current process’s stdio streams. The transport handles message streaming, dispatching, and shutdown operations, integrating with the MCP runtime ecosystem.

Implementations

impl StdioTransport

pub fn new(options: TransportOptions) -> Result<StdioTransport, TransportError>

Creates a new StdioTransport instance for MCP Server.

This constructor configures the transport to use the current process’s stdio streams,

Arguments

• options - Configuration options for the transport, including timeout settings.

Returns

A TransportResult containing the initialized StdioTransport instance.

Errors

Currently, this method does not fail, but it returns a TransportResult for API consistency.

pub fn create_with_server_launch<C>( command: C, args: Vec<String>, env: Option<HashMap<String, String>>, options: TransportOptions, ) -> Result<StdioTransport, TransportError>

where C: Into<String>,

Creates a new StdioTransport instance with a subprocess for MCP Client use.

This constructor configures the transport to launch a MCP Server with a specified command arguments and optional environment variables

Arguments

• command - The command to execute (e.g., “rust-mcp-filesystem”).
• args - Arguments to pass to the command. (e.g., “~/Documents”).
• env - Optional environment variables for the subprocess.
• options - Configuration options for the transport, including timeout settings.

Returns

A TransportResult containing the initialized StdioTransport instance, ready to launch the MCP server on start.

Trait Implementations

impl<R, S> Transport<R, S> for StdioTransport

where R: RpcMessage + Clone + Send + Sync + DeserializeOwned + 'static, S: McpMessage + Clone + Send + Sync + Serialize + 'static,

fn start<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<(Pin<Box<dyn Stream<Item = R> + Send>>, MessageDispatcher<R>, IoStream), TransportError>> + Send + 'async_trait>>

where 'life0: 'async_trait, MessageDispatcher<R>: McpDispatch<R, S>, StdioTransport: 'async_trait,

Starts the transport, initializing streams and the message dispatcher.

If configured with a command (MCP Client), launches the MCP server and connects its stdio streams. Otherwise, uses the current process’s stdio for server-side communication.

Returns

A TransportResult containing:

• A pinned stream of incoming messages.
• A MessageDispatcher<R> for sending messages.
• An IoStream for stderr (readable) or stdout (writable) depending on the mode.

Errors

Returns a TransportError if the subprocess fails to spawn or stdio streams cannot be accessed.

fn is_shut_down<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = bool> + Send + 'async_trait>>

where 'life0: 'async_trait, StdioTransport: 'async_trait,

Checks if the transport has been shut down.

fn shut_down<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<(), TransportError>> + Send + 'async_trait>>

where 'life0: 'async_trait, StdioTransport: 'async_trait,

Sends a shutdown signal via the watch channel and kills the subprocess if present.

Returns

A TransportResult indicating success or failure.

Errors

Returns a TransportError if the shutdown signal fails or the process cannot be killed.