The goblets of dawn are smashed. The weeping of the guitar begins.

Author: prestwich

.github/CODEOWNERS

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+*: @Evalir @prestwich @dylanlott
+.github/: @rswanson

.github/workflows/rust-ci.yml

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+name: Rust CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# simplest example of using the rust-base action
+jobs:
+  rust-base:
+    uses: init4tech/actions/.github/workflows/rust-base.yml@main

.gitignore

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+/target
+*/.DS_Store
+Cargo.lock

Cargo.toml

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+[package]
+name = "json-rpc-router"
+description = "Simple, modern, ergonomic JSON-RPC 2.0 method routing and basic servers"
+
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.81"
+authors = ["init4"]
+license = "MIT OR Apache-2.0"
+homepage = "https://github.com/init4tech/rpc"
+repository = "https://github.com/init4tech/rpc"
+
+[dependencies]
+bytes = "1.9.0"
+pin-project = "1.1.8"
+serde = { version = "1.0.217", features = ["derive"] }
+serde_json = "1.0.135"
+thiserror = "2.0.9"
+tokio = { version = "1.43.0", features = ["sync", "rt", "macros"] }
+tower = { version = "0.5.2", features = ["util"] }
+tracing = "0.1.41"
+
+# axum
+axum = { version = "0.8.1", optional = true }
+
+# pubsub
+tokio-stream = { version = "0.1.17", optional = true }
+
+# ipc
+interprocess = { version = "2.2.2", features = ["async", "tokio"], optional = true }
+tokio-util = { version = "0.7.13", optional = true, features = ["io"] }
+
+# ws
+tokio-tungstenite = { version = "0.26.1", features = ["rustls-tls-webpki-roots"], optional = true }
+futures-util = { version = "0.3.31", optional = true }
+
+[features]
+default = ["axum", "ws", "ipc"]
+axum = ["dep:axum"]
+pubsub = ["dep:tokio-stream"]
+ipc = ["pubsub", "dep:tokio-util", "dep:interprocess"]
+ws = ["pubsub", "dep:tokio-tungstenite", "dep:futures-util"]
+tokio-util = ["dep:tokio-util"]
+
+[profile.release]
+opt-level = 3
+lto = "thin"
+debug = "line-tables-only"
+strip = true
+panic = "unwind"
+codegen-units = 16
+
+[profile.profiling]
+inherits = "release"
+debug = 2
+strip = false
+
+[profile.bench]
+inherits = "profiling"
+
+[profile.ci-rust]
+inherits = "dev"
+strip = true
+debug = false
+incremental = false

LICENSE-APACHE

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+END OF TERMS AND CONDITIONS

LICENSE-MIT

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+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
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+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

README.md

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+## JSON-RPC Server and Methods
+
+A general-purpose, batteries-included [JSON-RPC 2.0] router, inspired by axum's
+routing system.
+
+### Concepts
+
+- A **Handler** is a function that processes some JSON input, and returns some
+  JSON output.
+- A **Method** is a handler with an associated name, which is used by the
+  incoming [request] to
+  identify that specific **Handler**.
+- A **Router** is a collection of **Methods**.
+- A **Server** exposes a **Router** over some transport.
+
+### Basic Usage
+
+```rust
+use json_rpc_router::{Router};
+
+// Provide methods called "double" and "add" to the router.
+let router = Router::<u64>::new()
+  // "double" returns the double of the request's parameter.
+  .route("double", |params: u64| async move {
+    Ok::<_, ()>(params * 2)
+  })
+  // "add" returns the sum of the request's parameters and the router's stored
+  // state.
+  .route("add", |params: u64, state: u64| async move {
+    Ok::<_, ()>(params + state)
+  // The router is provided with state, and is now ready to serve requests.
+  })
+  .with_state::<()>(3u64);
+```
+
+### Feature flags
+
+- `axum` - implements the `tower::Service` trait for `Router`, allowing it to
+  be used as an [axum]() handler.
+- `pubsub` - adds traits and tasks for serving the router over streaming
+  interfaces.
+- `ws` - adds implementations of the `pubsub` traits for
+  [tokio-tungstenite].
+- `ipc` - adds implementations of the `pubsub` traits for
+  [interprocess `local_sockets`].
+
+### Serving the Router
+
+We recommend [axum] for serving the router over HTTP. The `Router` provides an
+`into_axum(path: &str)` method to instantiate a new [`axum::Router`], and
+register the router to handle requests.
+
+For WS and IPC connections, the `pubsub` module provides implementations of the
+[`Connect`] trait for [`std::net::SocketAddr`] to create simple WS servers, and
+[`interprocess::local_socket::ListenerOptions`] to create simple IPC servers.
+Users with more complex needs should provide their own [`Connect`]
+implementations.
+
+[JSON-RPC 2.0]: https://www.jsonrpc.org/specification
+[request]: https://www.jsonrpc.org/specification#request_object
+[axum]: https://docs.rs/axum/latest/axum/
+[tokio-tungstenite]: https://docs.rs/tokio-tungstenite/latest/tokio_tungstenite/
+[`axum::Router`]: https://docs.rs/axum/latest/axum/struct.Router.html
+[interprocess `local_sockets`]: https://docs.rs/interprocess/latest/interprocess/local_socket/tokio/index.html
+[`interprocess::local_socket::ListenerOptions`]: https://docs.rs/interprocess/latest/interprocess/local_socket/struct.ListenerOptions.html
+[std::net::SocketAddr]: https://doc.rust-lang.org/std/net/enum.SocketAddr.html

src/axum.rs

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+use crate::{types::Response, HandlerArgs};
+use axum::{extract::FromRequest, response::IntoResponse};
+use bytes::Bytes;
+use std::{future::Future, pin::Pin};
+
+impl<S> axum::handler::Handler<Bytes, S> for crate::Router<S>
+where
+    S: Clone + Send + Sync + 'static,
+{
+    type Future = Pin<Box<dyn Future<Output = axum::response::Response> + Send>>;
+
+    fn call(self, req: axum::extract::Request, state: S) -> Self::Future {
+        Box::pin(async move {
+            let Ok(bytes) = Bytes::from_request(req, &state).await else {
+                return Box::<str>::from(Response::parse_error()).into_response();
+            };
+
+            let Ok(req) = crate::types::Request::try_from(bytes) else {
+                return Box::<str>::from(Response::parse_error()).into_response();
+            };
+
+            let args = HandlerArgs {
+                ctx: Default::default(),
+                req,
+            };
+
+            // Default handler ctx does not allow for notifications, which is
+            // what we want over HTTP.
+            let response = unwrap_infallible!(self.call_with_state(args, state).await);
+
+            Box::<str>::from(response).into_response()
+        })
+    }
+}