Struct StreamableHttpServerConfig 

#[non_exhaustive]
pub struct StreamableHttpServerConfig {
    pub sse_keep_alive: Option<Duration>,
    pub sse_retry: Option<Duration>,
    pub stateful_mode: bool,
    pub json_response: bool,
    pub cancellation_token: CancellationToken,
    pub allowed_hosts: Vec<String>,
    pub session_store: Option<Arc<dyn SessionStore>>,
}

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

sse_keep_alive: Option<Duration>

The ping message duration for SSE connections.

sse_retry: Option<Duration>

The retry interval for SSE priming events.

stateful_mode: bool

If true, the server will create a session for each request and keep it alive. When enabled, SSE priming events are sent to enable client reconnection.

json_response: bool

When true and stateful_mode is false, the server returns Content-Type: application/json directly instead of text/event-stream. This eliminates SSE framing overhead for simple request-response tools, allowed by the MCP Streamable HTTP spec (2025-06-18).

cancellation_token: CancellationToken

Cancellation token for the Streamable HTTP server.

When this token is cancelled, all active sessions are terminated and the server stops accepting new requests.

allowed_hosts: Vec<String>

Allowed hostnames or host:port authorities for inbound Host validation.

By default, Streamable HTTP servers only accept loopback hosts to prevent DNS rebinding attacks against locally running servers. Public deployments should override this list with their own hostnames. examples: allowed_hosts = [“localhost”, “127.0.0.1”, “0.0.0.0”] or with ports: allowed_hosts = [“example.com”, “example.com:8080”]

session_store: Option<Arc<dyn SessionStore>>

Optional external session store for cross-instance recovery.

When set, SessionState (the client’s initialize parameters) is persisted after a successful handshake and deleted when the session closes. On any subsequent request that arrives at an instance with no in-memory session, the store is consulted: if an entry is found the session is transparently restored so the client does not need to re-initialize.

Example

use std::sync::Arc;
use rmcp::transport::streamable_http_server::{
    StreamableHttpServerConfig, session::SessionStore,
};

let config = StreamableHttpServerConfig {
    session_store: Some(Arc::new(MyRedisStore::new())),
    ..Default::default()
};

Implementations

impl StreamableHttpServerConfig

pub fn with_allowed_hosts( self, allowed_hosts: impl IntoIterator<Item = impl Into<String>>, ) -> StreamableHttpServerConfig

pub fn disable_allowed_hosts(self) -> StreamableHttpServerConfig

Disable allowed hosts. This will allow requests with any Host header, which is NOT recommended for public deployments.

pub fn with_sse_keep_alive( self, duration: Option<Duration>, ) -> StreamableHttpServerConfig

pub fn with_sse_retry( self, duration: Option<Duration>, ) -> StreamableHttpServerConfig

pub fn with_stateful_mode(self, stateful: bool) -> StreamableHttpServerConfig

pub fn with_json_response( self, json_response: bool, ) -> StreamableHttpServerConfig

pub fn with_cancellation_token( self, token: CancellationToken, ) -> StreamableHttpServerConfig

Trait Implementations

impl Clone for StreamableHttpServerConfig

fn clone(&self) -> StreamableHttpServerConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StreamableHttpServerConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for StreamableHttpServerConfig

fn default() -> StreamableHttpServerConfig

Returns the “default value” for a type.