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use crate::codec::compression::{
CompressionEncoding, EnabledCompressionEncodings, SingleMessageCompressionOverride,
};
use crate::{
body::BoxBody,
codec::{encode_server, Codec, Streaming},
server::{ClientStreamingService, ServerStreamingService, StreamingService, UnaryService},
Code, Request, Status,
};
use http_body::Body;
use std::fmt;
use tokio_stream::{Stream, StreamExt};
macro_rules! t {
($result:expr) => {
match $result {
Ok(value) => value,
Err(status) => return status.to_http(),
}
};
}
/// A gRPC Server handler.
///
/// This will wrap some inner [`Codec`] and provide utilities to handle
/// inbound unary, client side streaming, server side streaming, and
/// bi-directional streaming.
///
/// Each request handler method accepts some service that implements the
/// corresponding service trait and a http request that contains some body that
/// implements some [`Body`].
pub struct Grpc<T> {
codec: T,
/// Which compression encodings does the server accept for requests?
accept_compression_encodings: EnabledCompressionEncodings,
/// Which compression encodings might the server use for responses.
send_compression_encodings: EnabledCompressionEncodings,
/// Limits the maximum size of a decoded message.
max_decoding_message_size: Option<usize>,
/// Limits the maximum size of an encoded message.
max_encoding_message_size: Option<usize>,
}
impl<T> Grpc<T>
where
T: Codec,
{
/// Creates a new gRPC server with the provided [`Codec`].
pub fn new(codec: T) -> Self {
Self {
codec,
accept_compression_encodings: EnabledCompressionEncodings::default(),
send_compression_encodings: EnabledCompressionEncodings::default(),
max_decoding_message_size: None,
max_encoding_message_size: None,
}
}
/// Enable accepting compressed requests.
///
/// If a request with an unsupported encoding is received the server will respond with
/// [`Code::UnUnimplemented`](crate::Code).
///
/// # Example
///
/// The most common way of using this is through a server generated by tonic-build:
///
/// ```rust
/// # enum CompressionEncoding { Gzip }
/// # struct Svc;
/// # struct ExampleServer<T>(T);
/// # impl<T> ExampleServer<T> {
/// # fn new(svc: T) -> Self { Self(svc) }
/// # fn accept_compressed(self, _: CompressionEncoding) -> Self { self }
/// # }
/// # #[tonic::async_trait]
/// # trait Example {}
///
/// #[tonic::async_trait]
/// impl Example for Svc {
/// // ...
/// }
///
/// let service = ExampleServer::new(Svc).accept_compressed(CompressionEncoding::Gzip);
/// ```
pub fn accept_compressed(mut self, encoding: CompressionEncoding) -> Self {
self.accept_compression_encodings.enable(encoding);
self
}
/// Enable sending compressed responses.
///
/// Requires the client to also support receiving compressed responses.
///
/// # Example
///
/// The most common way of using this is through a server generated by tonic-build:
///
/// ```rust
/// # enum CompressionEncoding { Gzip }
/// # struct Svc;
/// # struct ExampleServer<T>(T);
/// # impl<T> ExampleServer<T> {
/// # fn new(svc: T) -> Self { Self(svc) }
/// # fn send_compressed(self, _: CompressionEncoding) -> Self { self }
/// # }
/// # #[tonic::async_trait]
/// # trait Example {}
///
/// #[tonic::async_trait]
/// impl Example for Svc {
/// // ...
/// }
///
/// let service = ExampleServer::new(Svc).send_compressed(CompressionEncoding::Gzip);
/// ```
pub fn send_compressed(mut self, encoding: CompressionEncoding) -> Self {
self.send_compression_encodings.enable(encoding);
self
}
/// Limits the maximum size of a decoded message.
///
/// # Example
///
/// The most common way of using this is through a server generated by tonic-build:
///
/// ```rust
/// # struct Svc;
/// # struct ExampleServer<T>(T);
/// # impl<T> ExampleServer<T> {
/// # fn new(svc: T) -> Self { Self(svc) }
/// # fn max_decoding_message_size(self, _: usize) -> Self { self }
/// # }
/// # #[tonic::async_trait]
/// # trait Example {}
///
/// #[tonic::async_trait]
/// impl Example for Svc {
/// // ...
/// }
///
/// // Set the limit to 2MB, Defaults to 4MB.
/// let limit = 2 * 1024 * 1024;
/// let service = ExampleServer::new(Svc).max_decoding_message_size(limit);
/// ```
pub fn max_decoding_message_size(mut self, limit: usize) -> Self {
self.max_decoding_message_size = Some(limit);
self
}
/// Limits the maximum size of a encoded message.
///
/// # Example
///
/// The most common way of using this is through a server generated by tonic-build:
///
/// ```rust
/// # struct Svc;
/// # struct ExampleServer<T>(T);
/// # impl<T> ExampleServer<T> {
/// # fn new(svc: T) -> Self { Self(svc) }
/// # fn max_encoding_message_size(self, _: usize) -> Self { self }
/// # }
/// # #[tonic::async_trait]
/// # trait Example {}
///
/// #[tonic::async_trait]
/// impl Example for Svc {
/// // ...
/// }
///
/// // Set the limit to 2MB, Defaults to 4MB.
/// let limit = 2 * 1024 * 1024;
/// let service = ExampleServer::new(Svc).max_encoding_message_size(limit);
/// ```
pub fn max_encoding_message_size(mut self, limit: usize) -> Self {
self.max_encoding_message_size = Some(limit);
self
}
#[doc(hidden)]
pub fn apply_compression_config(
self,
accept_encodings: EnabledCompressionEncodings,
send_encodings: EnabledCompressionEncodings,
) -> Self {
let mut this = self;
for &encoding in CompressionEncoding::encodings() {
if accept_encodings.is_enabled(encoding) {
this = this.accept_compressed(encoding);
}
if send_encodings.is_enabled(encoding) {
this = this.send_compressed(encoding);
}
}
this
}
#[doc(hidden)]
pub fn apply_max_message_size_config(
self,
max_decoding_message_size: Option<usize>,
max_encoding_message_size: Option<usize>,
) -> Self {
let mut this = self;
if let Some(limit) = max_decoding_message_size {
this = this.max_decoding_message_size(limit);
}
if let Some(limit) = max_encoding_message_size {
this = this.max_encoding_message_size(limit);
}
this
}
/// Handle a single unary gRPC request.
pub async fn unary<S, B>(
&mut self,
mut service: S,
req: http::Request<B>,
) -> http::Response<BoxBody>
where
S: UnaryService<T::Decode, Response = T::Encode>,
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send,
{
let accept_encoding = CompressionEncoding::from_accept_encoding_header(
req.headers(),
self.send_compression_encodings,
);
let request = match self.map_request_unary(req).await {
Ok(r) => r,
Err(status) => {
return self.map_response::<tokio_stream::Once<Result<T::Encode, Status>>>(
Err(status),
accept_encoding,
SingleMessageCompressionOverride::default(),
self.max_encoding_message_size,
);
}
};
let response = service
.call(request)
.await
.map(|r| r.map(|m| tokio_stream::once(Ok(m))));
let compression_override = compression_override_from_response(&response);
self.map_response(
response,
accept_encoding,
compression_override,
self.max_encoding_message_size,
)
}
/// Handle a server side streaming request.
pub async fn server_streaming<S, B>(
&mut self,
mut service: S,
req: http::Request<B>,
) -> http::Response<BoxBody>
where
S: ServerStreamingService<T::Decode, Response = T::Encode>,
S::ResponseStream: Send + 'static,
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send,
{
let accept_encoding = CompressionEncoding::from_accept_encoding_header(
req.headers(),
self.send_compression_encodings,
);
let request = match self.map_request_unary(req).await {
Ok(r) => r,
Err(status) => {
return self.map_response::<S::ResponseStream>(
Err(status),
accept_encoding,
SingleMessageCompressionOverride::default(),
self.max_encoding_message_size,
);
}
};
let response = service.call(request).await;
self.map_response(
response,
accept_encoding,
// disabling compression of individual stream items must be done on
// the items themselves
SingleMessageCompressionOverride::default(),
self.max_encoding_message_size,
)
}
/// Handle a client side streaming gRPC request.
pub async fn client_streaming<S, B>(
&mut self,
mut service: S,
req: http::Request<B>,
) -> http::Response<BoxBody>
where
S: ClientStreamingService<T::Decode, Response = T::Encode>,
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send + 'static,
{
let accept_encoding = CompressionEncoding::from_accept_encoding_header(
req.headers(),
self.send_compression_encodings,
);
let request = t!(self.map_request_streaming(req));
let response = service
.call(request)
.await
.map(|r| r.map(|m| tokio_stream::once(Ok(m))));
let compression_override = compression_override_from_response(&response);
self.map_response(
response,
accept_encoding,
compression_override,
self.max_encoding_message_size,
)
}
/// Handle a bi-directional streaming gRPC request.
pub async fn streaming<S, B>(
&mut self,
mut service: S,
req: http::Request<B>,
) -> http::Response<BoxBody>
where
S: StreamingService<T::Decode, Response = T::Encode> + Send,
S::ResponseStream: Send + 'static,
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send,
{
let accept_encoding = CompressionEncoding::from_accept_encoding_header(
req.headers(),
self.send_compression_encodings,
);
let request = t!(self.map_request_streaming(req));
let response = service.call(request).await;
self.map_response(
response,
accept_encoding,
SingleMessageCompressionOverride::default(),
self.max_encoding_message_size,
)
}
async fn map_request_unary<B>(
&mut self,
request: http::Request<B>,
) -> Result<Request<T::Decode>, Status>
where
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send,
{
let request_compression_encoding = self.request_encoding_if_supported(&request)?;
let (parts, body) = request.into_parts();
let stream = Streaming::new_request(
self.codec.decoder(),
body,
request_compression_encoding,
self.max_decoding_message_size,
);
tokio::pin!(stream);
let message = stream
.try_next()
.await?
.ok_or_else(|| Status::new(Code::Internal, "Missing request message."))?;
let mut req = Request::from_http_parts(parts, message);
if let Some(trailers) = stream.trailers().await? {
req.metadata_mut().merge(trailers);
}
Ok(req)
}
fn map_request_streaming<B>(
&mut self,
request: http::Request<B>,
) -> Result<Request<Streaming<T::Decode>>, Status>
where
B: Body + Send + 'static,
B::Error: Into<crate::Error> + Send,
{
let encoding = self.request_encoding_if_supported(&request)?;
let request = request.map(|body| {
Streaming::new_request(
self.codec.decoder(),
body,
encoding,
self.max_decoding_message_size,
)
});
Ok(Request::from_http(request))
}
fn map_response<B>(
&mut self,
response: Result<crate::Response<B>, Status>,
accept_encoding: Option<CompressionEncoding>,
compression_override: SingleMessageCompressionOverride,
max_message_size: Option<usize>,
) -> http::Response<BoxBody>
where
B: Stream<Item = Result<T::Encode, Status>> + Send + 'static,
{
let response = match response {
Ok(r) => r,
Err(status) => return status.to_http(),
};
let (mut parts, body) = response.into_http().into_parts();
// Set the content type
parts.headers.insert(
http::header::CONTENT_TYPE,
http::header::HeaderValue::from_static("application/grpc"),
);
#[cfg(any(feature = "gzip", feature = "zstd"))]
if let Some(encoding) = accept_encoding {
// Set the content encoding
parts.headers.insert(
crate::codec::compression::ENCODING_HEADER,
encoding.into_header_value(),
);
}
let body = encode_server(
self.codec.encoder(),
body,
accept_encoding,
compression_override,
max_message_size,
);
http::Response::from_parts(parts, BoxBody::new(body))
}
fn request_encoding_if_supported<B>(
&self,
request: &http::Request<B>,
) -> Result<Option<CompressionEncoding>, Status> {
CompressionEncoding::from_encoding_header(
request.headers(),
self.accept_compression_encodings,
)
}
}
impl<T: fmt::Debug> fmt::Debug for Grpc<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut f = f.debug_struct("Grpc");
f.field("codec", &self.codec);
f.field(
"accept_compression_encodings",
&self.accept_compression_encodings,
);
f.field(
"send_compression_encodings",
&self.send_compression_encodings,
);
f.finish()
}
}
fn compression_override_from_response<B, E>(
res: &Result<crate::Response<B>, E>,
) -> SingleMessageCompressionOverride {
res.as_ref()
.ok()
.and_then(|response| {
response
.extensions()
.get::<SingleMessageCompressionOverride>()
.copied()
})
.unwrap_or_default()
}