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// Copyright 2019-2021 Parity Technologies (UK) Ltd.
//
// 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,
// publish, distribute, sublicense, and/or sell copies of
// 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.
//! # jsonrpsee-proc-macros
#![cfg_attr(not(test), warn(unused_crate_dependencies))]
#![cfg_attr(docsrs, feature(doc_cfg))]
use proc_macro::TokenStream;
use rpc_macro::RpcDescription;
mod attributes;
mod helpers;
mod render_client;
mod render_server;
mod rpc_macro;
pub(crate) mod visitor;
/// Main RPC macro.
///
/// ## Description
///
/// This macro is capable of generating both server and client implementations on demand.
/// Based on the attributes provided to the `rpc` macro, either one or both of implementations
/// will be generated.
///
/// For clients, it will be an extension trait that adds all the required methods to a
/// type that implements `Client` or `SubscriptionClient` (depending on whether trait has
/// subscriptions methods or not), namely `HttpClient` and `WsClient`.
///
/// For servers, it will generate a trait mostly equivalent to the input, with the following differences:
///
/// - The trait will have one additional (already implemented) method, `into_rpc`, which turns any object that
/// implements the server trait into an `RpcModule`.
/// - For subscription methods:
/// - There will be one additional argument inserted right after `&self`: `subscription_sink: SubscriptionSink`.
/// It should be used to accept or reject a subscription and send data back to the subscribers.
/// - The return type of the subscription method must implement `IntoSubscriptionCloseResponse`.
///
/// Since this macro can generate up to two traits, both server and client traits will have
/// a new name. For the `Foo` trait, server trait will be named `FooServer`, and client,
/// correspondingly, `FooClient`.
///
/// To use the `FooClient`, just import it in the context. To use the server, the `FooServer` trait must be implemented
/// on your type first.
///
/// Note: you need to import the `jsonrpsee` façade crate in your code for the macro to work properly.
///
/// ## Prerequisites
///
/// - Implementors of the server trait must be `Sync`, `Send`, `Sized` and `'static`. If you want to implement this
/// trait on some type that is not thread-safe, consider using `Arc<RwLock<..>>`.
///
/// ## Examples
///
/// Below you can find examples of the macro usage along with the code
/// that generated for it by the macro.
///
/// ```ignore
/// #[rpc(client, server, namespace = "foo")]
/// pub trait Rpc {
/// #[method(name = "foo")]
/// async fn async_method(&self, param_a: u8, param_b: String) -> u16;
/// #[method(name = "bar")]
/// fn sync_method(&self) -> String;
///
/// #[subscription(name = "subscribe", item = "String")]
/// async fn sub(&self) -> SubscriptionResult;
/// }
/// ```
///
/// Server code that will be generated:
///
/// ```ignore
/// #[async_trait]
/// pub trait RpcServer {
/// // RPC methods are normal methods and can be either sync or async.
/// async fn async_method(&self, param_a: u8, param_b: String) -> u16;
/// fn sync_method(&self) -> String;
///
/// // Note that `pending_subscription_sink` was added automatically.
/// async fn sub(&self, pending: PendingSubscriptionSink) -> SubscriptionResult;
///
/// fn into_rpc(self) -> Result<Self, jsonrpsee::core::Error> {
/// // Actual implementation stripped, but inside we will create
/// // a module with one method and one subscription
/// }
/// }
/// ```
///
/// Client code that will be generated:
///
/// ```ignore
/// #[async_trait]
/// pub trait RpcClient: SubscriptionClient {
/// // In client implementation all the methods are (obviously) async.
/// async fn async_method(&self, param_a: u8, param_b: String) -> Result<u16, Error> {
/// // Actual implementations are stripped, but inside a corresponding `Client` or
/// // `SubscriptionClient` method is called.
/// }
/// async fn sync_method(&self) -> Result<String, Error> {
/// // ...
/// }
///
/// // Subscription method returns `Subscription` object in case of success.
/// async fn sub(&self) -> Result<Subscription<String>, Error> {
/// // ...
/// }
/// }
///
/// impl<T> RpcClient for T where T: SubscriptionClient {}
/// ```
///
/// ## Attributes
///
/// ### `rpc` attribute
///
/// `rpc` attribute is applied to a trait in order to turn it into an RPC implementation.
///
/// **Arguments:**
///
/// - `server`: generate `<Trait>Server` trait for the server implementation.
/// - `client`: generate `<Trait>Client` extension trait that builds RPC clients to invoke a concrete RPC
/// implementation's methods conveniently.
/// - `namespace`: add a prefix to all the methods and subscriptions in this RPC. For example, with namespace `foo` and
/// method `spam`, the resulting method name will be `foo_spam`.
/// - `server_bounds`: replace *all* auto-generated trait bounds with the user-defined ones for the server
/// implementation.
/// - `client_bounds`: replace *all* auto-generated trait bounds with the user-defined ones for the client
/// implementation.
///
/// **Trait requirements:**
///
/// A trait wrapped with the `rpc` attribute **must not**:
///
/// - have associated types or constants;
/// - have Rust methods not marked with either the `method` or `subscription` attribute;
/// - be empty.
///
/// At least one of the `server` or `client` flags must be provided, otherwise the compilation will err.
///
/// ### `method` attribute
///
/// `method` attribute is used to define an RPC method.
///
/// **Arguments:**
///
/// - `name` (mandatory): name of the RPC method. Does not have to be the same as the Rust method name.
/// - `aliases`: list of name aliases for the RPC method as a comma separated string.
/// Aliases are processed ignoring the namespace, so add the complete name, including the
/// namespace.
/// - `blocking`: when set method execution will always spawn on a dedicated thread. Only usable with non-`async` methods.
/// - `param_kind`: kind of structure to use for parameter passing. Can be "array" or "map", defaults to "array".
///
/// **Method requirements:**
///
/// A Rust method marked with the `method` attribute, **may**:
///
/// - be either `async` or not;
/// - have input parameters or not;
/// - have a return value or not (in the latter case, it will be considered a notification method).
///
/// ### `subscription` attribute
///
/// `subscription` attribute is used to define a publish/subscribe interface according to the [ethereum pubsub specification](https://geth.ethereum.org/docs/rpc/pubsub)
///
/// **Arguments:**
///
/// - `name` (mandatory): name of the RPC method. Does not have to be the same as the Rust method name.
/// - `unsubscribe` (optional): name of the RPC method to unsubscribe from the subscription. Must not be the same as `name`.
/// This is generated for you if the subscription name starts with `subscribe`.
/// - `aliases` (optional): aliases for `name`. Aliases are processed ignoring the namespace,
/// so add the complete name, including the namespace.
/// - `unsubscribe_aliases` (optional): Similar to `aliases` but for `unsubscribe`.
/// - `item` (mandatory): type of items yielded by the subscription. Note that it must be the type, not string.
/// - `param_kind`: kind of structure to use for parameter passing. Can be "array" or "map", defaults to "array".
///
/// **Method requirements:**
///
/// Rust method marked with the `subscription` attribute **must**:
///
/// - be asynchronous;
/// - return a type that implements `jsonrpsee::server::IntoSubscriptionCloseResponse`.
///
/// Rust method marked with `subscription` attribute **may**:
///
/// - have input parameters or not.
///
/// ### `argument` attribute
///
/// `argument` attribute is used to modify a function argument.
///
/// **Arguments:**
///
/// - `rename`: rename the generated JSON key.
///
///
/// ## Full workflow example
///
/// ```rust
/// //! Example of using proc macro to generate working client and server.
///
/// use std::net::SocketAddr;
///
/// use futures_channel::oneshot;
/// use jsonrpsee::{ws_client::*, server::ServerBuilder};
///
/// // RPC is put into a separate module to clearly show names of generated entities.
/// mod rpc_impl {
/// use jsonrpsee::{proc_macros::rpc, Extensions};
/// use jsonrpsee::server::{PendingSubscriptionSink, SubscriptionMessage, IntoSubscriptionCloseResponse, SubscriptionCloseResponse};
/// use jsonrpsee::core::{async_trait, RpcResult, SubscriptionResult};
///
/// enum CloseResponse {
/// None,
/// Failed,
/// }
///
/// impl IntoSubscriptionCloseResponse for CloseResponse {
/// fn into_response(self) -> SubscriptionCloseResponse {
/// match self {
/// // Do not send a close response when the subscription is terminated.
/// CloseResponse::None => SubscriptionCloseResponse::None,
/// // Send a close response as an ordinary subscription notification
/// // when the subscription is terminated.
/// CloseResponse::Failed => SubscriptionCloseResponse::Notif("failed".into()),
/// }
/// }
/// }
///
/// // Generate both server and client implementations, prepend all the methods with `foo_` prefix.
/// #[rpc(client, server, namespace = "foo")]
/// pub trait MyRpc {
/// #[method(name = "foo")]
/// async fn async_method(
/// &self,
/// param_a: u8,
/// #[argument(rename = "param_c")]
/// param_b: String
/// ) -> RpcResult<u16>;
///
/// #[method(name = "bar")]
/// fn sync_method(&self) -> RpcResult<u16>;
///
/// #[method(name = "baz", blocking)]
/// fn blocking_method(&self) -> RpcResult<u16>;
///
/// /// Override the `foo_sub` and use `foo_subNotif` for the notifications.
/// ///
/// /// The item field indicates which type goes into result field below.
/// ///
/// /// The notification format:
/// ///
/// /// ```
/// /// {
/// /// "jsonrpc":"2.0",
/// /// "method":"foo_subNotif",
/// /// "params":["subscription":"someID", "result":"some string"]
/// /// }
/// /// ```
/// #[subscription(name = "sub" => "subNotif", unsubscribe = "unsub", item = String)]
/// async fn sub_override_notif_method(&self) -> SubscriptionResult;
///
/// /// Use the same method name for both the `subscribe call` and `notifications`
/// ///
/// /// The unsubscribe method name is generated here `foo_unsubscribe`
/// /// Thus the `unsubscribe attribute` is not needed unless a custom unsubscribe method name is wanted.
/// ///
/// /// The notification format:
/// ///
/// /// ```
/// /// {
/// /// "jsonrpc":"2.0",
/// /// "method":"foo_subscribe",
/// /// "params":["subscription":"someID", "result":"some string"]
/// /// }
/// /// ```
/// #[subscription(name = "subscribe", item = String)]
/// async fn sub(&self) -> SubscriptionResult;
///
/// #[subscription(name = "sub_custom_close_msg", unsubscribe = "unsub_custom_close_msg", item = String)]
/// async fn sub_custom_close_msg(&self) -> CloseResponse;
/// }
///
/// // Structure that will implement the `MyRpcServer` trait.
/// // It can have fields, if required, as long as it's still `Send + Sync + 'static`.
/// pub struct RpcServerImpl;
///
/// // Note that the trait name we use is `MyRpcServer`, not `MyRpc`!
/// #[async_trait]
/// impl MyRpcServer for RpcServerImpl {
/// async fn async_method(&self, _param_a: u8, _param_b: String) -> RpcResult<u16> {
/// Ok(42)
/// }
///
/// fn sync_method(&self) -> RpcResult<u16> {
/// Ok(10)
/// }
///
/// fn blocking_method(&self) -> RpcResult<u16> {
/// // This will block current thread for 1 second, which is fine since we marked
/// // this method as `blocking` above.
/// std::thread::sleep(std::time::Duration::from_millis(1000));
/// Ok(11)
/// }
///
/// // The stream API can be used to pipe items from the underlying stream
/// // as subscription responses.
/// async fn sub_override_notif_method(&self, pending: PendingSubscriptionSink) -> SubscriptionResult {
/// let mut sink = pending.accept().await?;
/// sink.send("Response_A".into()).await?;
/// Ok(())
/// }
///
/// // Send out two values on the subscription.
/// async fn sub(&self, pending: PendingSubscriptionSink) -> SubscriptionResult {
/// let sink = pending.accept().await?;
///
/// let msg1 = SubscriptionMessage::from("Response_A");
/// let msg2 = SubscriptionMessage::from("Response_B");
///
/// sink.send(msg1).await?;
/// sink.send(msg2).await?;
///
/// Ok(())
/// }
///
/// // If one doesn't want sent out a close message when a subscription terminates or treat
/// // errors as subscription error notifications then it's possible to implement
/// // `IntoSubscriptionCloseResponse` for customized behavior.
/// async fn sub_custom_close_msg(&self, pending: PendingSubscriptionSink) -> CloseResponse {
/// let Ok(sink) = pending.accept().await else {
/// return CloseResponse::None;
/// };
///
/// if sink.send("Response_A".into()).await.is_ok() {
/// CloseResponse::Failed
/// } else {
/// CloseResponse::None
/// }
///
/// }
/// }
/// }
///
/// // Use the generated implementations of server and client.
/// use rpc_impl::{MyRpcClient, MyRpcServer, RpcServerImpl};
///
/// pub async fn server() -> SocketAddr {
/// let server = ServerBuilder::default().build("127.0.0.1:0").await.unwrap();
/// let addr = server.local_addr().unwrap();
/// let server_handle = server.start(RpcServerImpl.into_rpc());
///
/// // `into_rpc()` method was generated inside of the `RpcServer` trait under the hood.
/// tokio::spawn(server_handle.stopped());
///
/// addr
/// }
///
/// // In the main function, we start the server, create a client connected to this server,
/// // and call the available methods.
/// #[tokio::main]
/// async fn main() {
/// let server_addr = server().await;
/// let server_url = format!("ws://{}", server_addr);
/// // Note that we create the client as usual, but thanks to the `use rpc_impl::MyRpcClient`,
/// // the client object will have all the methods to interact with the server.
/// let client = WsClientBuilder::default().build(&server_url).await.unwrap();
///
/// // Invoke RPC methods.
/// assert_eq!(client.async_method(10, "a".into()).await.unwrap(), 42);
/// assert_eq!(client.sync_method().await.unwrap(), 10);
///
/// // Subscribe and receive messages from the subscription.
/// let mut sub = client.sub().await.unwrap();
/// let first_recv = sub.next().await.unwrap().unwrap();
/// assert_eq!(first_recv, "Response_A".to_string());
/// let second_recv = sub.next().await.unwrap().unwrap();
/// assert_eq!(second_recv, "Response_B".to_string());
/// }
/// ```
#[proc_macro_attribute]
pub fn rpc(attr: TokenStream, item: TokenStream) -> TokenStream {
let rebuilt_rpc_attribute = syn::Attribute {
pound_token: syn::token::Pound::default(),
style: syn::AttrStyle::Outer,
bracket_token: syn::token::Bracket::default(),
meta: syn::Meta::List(syn::MetaList {
path: syn::Ident::new("rpc", proc_macro2::Span::call_site()).into(),
delimiter: syn::MacroDelimiter::Paren(syn::token::Paren(proc_macro2::Span::call_site())),
tokens: attr.into(),
}),
};
match rpc_impl(rebuilt_rpc_attribute, item) {
Ok(tokens) => tokens,
Err(err) => err.to_compile_error(),
}
.into()
}
/// Convenience form of `rpc` that may use `?` for error handling to avoid boilerplate.
fn rpc_impl(attr: syn::Attribute, item: TokenStream) -> Result<proc_macro2::TokenStream, syn::Error> {
let trait_data: syn::ItemTrait = syn::parse(item)?;
let rpc = RpcDescription::from_item(attr, trait_data)?;
rpc.render()
}