Struct tonic::Streaming

pub struct Streaming<T> { /* private fields */ }

Streaming requests and responses.

This will wrap some inner Body and Decoder and provide an interface to fetch the message stream and trailing metadata

Implementations

impl<T> Streaming<T>

pub async fn message(&mut self) -> Result<Option<T>, Status>

Fetch the next message from this stream.

Return value

• Result::Err(val) means a gRPC error was sent by the sender instead of a valid response message. Refer to Status::code and Status::message to examine possible error causes.

• Result::Ok(None) means the stream was closed by the sender and no more messages will be delivered. Further attempts to call Streaming::message will result in the same return value.

• Result::Ok(Some(val)) means the sender streamed a valid response message val.

if let Some(next_message) = request.message().await? {
    println!("{:?}", next_message);
}

pub async fn trailers(&mut self) -> Result<Option<MetadataMap>, Status>

Fetch the trailing metadata.

This will drain the stream of all its messages to receive the trailing metadata. If Streaming::message returns None then this function will not need to poll for trailers since the body was totally consumed.

if let Some(metadata) = request.trailers().await? {
    println!("{:?}", metadata);
}

Trait Implementations

impl<T> Debug for Streaming<T>

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

Formats the value using the given formatter.

impl<T> Stream for Streaming<T>

type Item = Result<T, Status>

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<T> Unpin for Streaming<T>