ServiceDispatcher

roam_session

Trait ServiceDispatcher 

Source 
pub trait ServiceDispatcher: Send + Sync {
    // Required methods
    fn method_ids(&self) -> Vec<u64>;
    fn dispatch(
        &self,
        cx: &Context,
        payload: Vec<u8>,
        registry: &mut ChannelRegistry,
    ) -> Pin<Box<dyn Future<Output = ()> + Send + 'static>>;
}
Expand description

Trait for dispatching requests to a service.

The dispatcher handles both simple and channeling methods uniformly. Stream binding is done via reflection (Poke) on the deserialized args.

Required Methods§

Source

fn method_ids(&self) -> Vec<u64>

Returns the method IDs this dispatcher handles.

Used by RoutedDispatcher to determine which methods to route to which dispatcher.

Source

fn dispatch( &self, cx: &Context, payload: Vec<u8>, registry: &mut ChannelRegistry, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'static>>

Dispatch a request and send the response via the task channel.

The dispatcher is responsible for:

  • Looking up the method by cx.method_id()
  • Deserializing arguments from payload
  • Patching channel IDs from cx.channels() into deserialized args via patch_channel_ids()
  • Binding any Tx/Rx streams via the registry
  • Calling the service method
  • Sending Data/Close messages for any Tx streams
  • Sending the Response message via DriverMessage::Response

By using a single channel for Data/Close/Response, correct ordering is guaranteed: all stream Data and Close messages are sent before the Response.

The cx.channels() contains channel IDs from the Request message framing, in declaration order. For a ForwardingDispatcher, this enables transparent proxying without parsing the payload.

Returns a boxed future with 'static lifetime so it can be spawned. Implementations should clone their service into the future to achieve this.

r[impl channeling.allocation.caller] - Stream IDs are from Request.channels (caller allocated).

Implementors§