feat(examples): use cbor codec in file-sharing example

Remove the use of the core `upgrade::transfer` module in `file-sharing` example in favor of `cbor` codec.

Related #4011.

Pull-Request: #4036.

Cargo.lock

@@ -1534,13 +1534,13 @@ name = "file-sharing"
 version = "0.1.0"
 dependencies = [
  "async-std",
- "async-trait",
  "clap",
  "either",
  "env_logger 0.10.0",
  "futures",
  "libp2p",
  "multiaddr",
+ "serde",
  "void",
 ]
 

examples/file-sharing/Cargo.toml

@@ -6,12 +6,12 @@ publish = false
 license = "MIT"
 
 [dependencies]
+serde = { version = "1.0", features = ["derive"] }
 async-std = { version = "1.12", features = ["attributes"] }
-async-trait = "0.1"
 clap = { version = "4.3.1", features = ["derive"] }
 either = "1.8"
 env_logger = "0.10"
 futures = "0.3.28"
-libp2p = { path = "../../libp2p", features = ["async-std", "dns", "kad", "noise", "macros", "request-response", "tcp", "websocket", "yamux"] }
+libp2p = { path = "../../libp2p", features = ["async-std", "cbor", "dns", "kad", "noise", "macros", "request-response", "tcp", "websocket", "yamux"] }
 multiaddr = { version = "0.17.1" }
 void = "1.0.2"

examples/file-sharing/src/network.rs

@@ -1,14 +1,10 @@
 use async_std::io;
-use async_trait::async_trait;
 use either::Either;
 use futures::channel::{mpsc, oneshot};
 use futures::prelude::*;
 
 use libp2p::{
-    core::{
-        upgrade::{read_length_prefixed, write_length_prefixed},
-        Multiaddr,
-    },
+    core::Multiaddr,
     identity,
     kad::{
         record::store::MemoryStore, GetProvidersOk, Kademlia, KademliaEvent, QueryId, QueryResult,
@@ -22,9 +18,9 @@ use libp2p::{
 
 use libp2p::core::upgrade::Version;
 use libp2p::StreamProtocol;
+use serde::{Deserialize, Serialize};
 use std::collections::{hash_map, HashMap, HashSet};
 use std::error::Error;
-use std::iter;
 
 /// Creates the network components, namely:
 ///
@@ -60,13 +56,12 @@ pub(crate) async fn new(
         transport,
         ComposedBehaviour {
             kademlia: Kademlia::new(peer_id, MemoryStore::new(peer_id)),
-            request_response: request_response::Behaviour::with_codec(
-                FileExchangeCodec(),
-                iter::once((
+            request_response: request_response::cbor::Behaviour::new(
+                [(
                     StreamProtocol::new("/file-exchange/1"),
                     ProtocolSupport::Full,
-                )),
-                Default::default(),
+                )],
+                request_response::Config::default(),
             ),
         },
         peer_id,
@@ -413,7 +408,7 @@ impl EventLoop {
 #[derive(NetworkBehaviour)]
 #[behaviour(to_swarm = "ComposedEvent")]
 struct ComposedBehaviour {
-    request_response: request_response::Behaviour<FileExchangeCodec>,
+    request_response: request_response::cbor::Behaviour<FileRequest, FileResponse>,
     kademlia: Kademlia<MemoryStore>,
 }
 
@@ -474,77 +469,7 @@ pub(crate) enum Event {
 }
 
 // Simple file exchange protocol
-
-#[derive(Clone)]
-struct FileExchangeCodec();
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 struct FileRequest(String);
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub(crate) struct FileResponse(Vec<u8>);
-
-#[async_trait]
-impl request_response::Codec for FileExchangeCodec {
-    type Protocol = StreamProtocol;
-    type Request = FileRequest;
-    type Response = FileResponse;
-
-    async fn read_request<T>(&mut self, _: &StreamProtocol, io: &mut T) -> io::Result<Self::Request>
-    where
-        T: AsyncRead + Unpin + Send,
-    {
-        let vec = read_length_prefixed(io, 1_000_000).await?;
-
-        if vec.is_empty() {
-            return Err(io::ErrorKind::UnexpectedEof.into());
-        }
-
-        Ok(FileRequest(String::from_utf8(vec).unwrap()))
-    }
-
-    async fn read_response<T>(
-        &mut self,
-        _: &StreamProtocol,
-        io: &mut T,
-    ) -> io::Result<Self::Response>
-    where
-        T: AsyncRead + Unpin + Send,
-    {
-        let vec = read_length_prefixed(io, 500_000_000).await?; // update transfer maximum
-
-        if vec.is_empty() {
-            return Err(io::ErrorKind::UnexpectedEof.into());
-        }
-
-        Ok(FileResponse(vec))
-    }
-
-    async fn write_request<T>(
-        &mut self,
-        _: &StreamProtocol,
-        io: &mut T,
-        FileRequest(data): FileRequest,
-    ) -> io::Result<()>
-    where
-        T: AsyncWrite + Unpin + Send,
-    {
-        write_length_prefixed(io, data).await?;
-        io.close().await?;
-
-        Ok(())
-    }
-
-    async fn write_response<T>(
-        &mut self,
-        _: &StreamProtocol,
-        io: &mut T,
-        FileResponse(data): FileResponse,
-    ) -> io::Result<()>
-    where
-        T: AsyncWrite + Unpin + Send,
-    {
-        write_length_prefixed(io, data).await?;
-        io.close().await?;
-
-        Ok(())
-    }
-}

libp2p/Cargo.toml

@@ -14,6 +14,7 @@ categories = ["network-programming", "asynchronous"]
 full = [
     "async-std",
     "autonat",
+    "cbor",
     "dcutr",
     "deflate",
     "dns",
@@ -49,6 +50,7 @@ full = [
 
 async-std = ["libp2p-swarm/async-std", "libp2p-mdns?/async-io", "libp2p-tcp?/async-io", "libp2p-dns?/async-std"]
 autonat = ["dep:libp2p-autonat"]
+cbor = ["libp2p-request-response?/cbor"]
 dcutr = ["dep:libp2p-dcutr", "libp2p-metrics?/dcutr"]
 deflate = ["dep:libp2p-deflate"]
 dns = ["dep:libp2p-dns"]