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//! Futures + JSON-RPC //! //! A lightweight remote procedure call protocol. It is designed to be simple! And, with futures, even more flexible! //! //! This crate will associate [Future](futures::future::Future)s with method signatures via [register_method](handler::JrpcHandler::register_method), and parse/handle JSON-RPC messages via [handle_message](handler::JrpcHandler::handle_message). //! //! It is fully compliant with [JSON-RPC 2.0 Specification](https://www.jsonrpc.org/specification). //! //! ## Installation //! //! Add this to your `Cargo.toml`: //! //! ```toml //! [dependencies] //! futures_jsonrpc = "0.2" //! ``` //! //! ## Minimal example //! //! ``` //! use futures_jsonrpc::futures::prelude::*; //! use futures_jsonrpc::*; //! use serde_json::Number; //! //! // This macro will avoid some boilerplating, leaving only the `Future` implementation to be done //! // //! // Check for additional information in the detailed explanation below //! // //! // Also, check `generate_method_with_data_and_future` and `generate_method_with_lifetime_data_and_future` //! generate_method!( //! CopyParams, //! impl Future for CopyParams { //! type Item = Option<JrpcResponse>; //! type Error = ErrorVariant; //! //! fn poll(&mut self) -> Result<Async<Self::Item>, Self::Error> { //! let request = self.get_request()?; //! let params = request.get_params().clone().unwrap_or(JsonValue::Null); //! //! let message = JrpcResponseParam::generate_result(params) //! .and_then(|result| request.generate_response(result))?; //! //! Ok(Async::Ready(Some(message))) //! } //! } //! ); //! //! fn main() { //! // `JrpcHandler` instance is responsible for registering the JSON-RPC methods and receiving the //! // requests. //! // //! // This is full `Arc`/`RwLock` protected. Therefore, it can be freely copied/sent among //! // threads. //! let handler = JrpcHandler::new().unwrap(); //! //! handler //! // `register_method` will tie the method signature to an instance, not a generic. This //! // means we can freely mutate this instance across different signatures. //! .register_method("some/copyParams", CopyParams::new().unwrap()) //! //! .and_then(|h| { //! // `handle_message` will receive a raw implementation of `ToString` and return the //! // associated future. If no future is found, an instance of //! // `Err(ErrorVariant::MethodSignatureNotFound(String))` is returned //! h.handle_message( //! r#" //! { //! "jsonrpc": "2.0", //! "method": "some/copyParams", //! "params": [42, 23], //! "id": 531 //! }"#, //! ) //! }) //! //! // Just waiting for the poll of future. Check futures documentation. //! .and_then(|future| future.wait()) //! .and_then(|result| { //! // The result is an instance of `JrpcResponse` //! let result = result.unwrap(); //! //! assert_eq!(result.get_jsonrpc(), "2.0"); //! assert_eq!( //! result.get_result(), //! &Some(JsonValue::Array(vec![ //! JsonValue::Number(Number::from(42)), //! JsonValue::Number(Number::from(23)), //! ])) //! ); //! assert!(result.get_error().is_none()); //! assert_eq!(result.get_id(), &JsonValue::Number(Number::from(531))); //! Ok(()) //! }) //! .unwrap(); //! } //! ``` //! //! ## Detailed explanation //! //! ``` //! use futures_jsonrpc::futures::prelude::*; //! use futures_jsonrpc::*; //! use std::marker::PhantomData; //! //! // `JrpcHandler` use foreign structures as controllers //! // This example will reflect `generate_method_with_lifetime_data_and_future` macro //! #[derive(Debug, Clone)] //! pub struct CopyParams<'r> { //! request: Option<JrpcRequest>, //! data: (String, i32, PhantomData<&'r ()>), //! } //! //! // This implementation is essentially some boilerplate to hold the data that may be used by the //! // future poll //! impl<'r> CopyParams<'r> { //! // The `new` method will always receive a n-tuple as parameter to store data //! // //! // It is recommended to use atomic types, or `Arc` protected for heavy data. At every request, //! // we `Clone` this struct to send it to the responsible thread //! pub fn new(data: (String, i32, PhantomData<&'r ()>)) -> Result<Self, ErrorVariant> { //! let request = None; //! let some_notification = CopyParams { request, data }; //! Ok(some_notification) //! } //! //! // The `get_data` will support the future poll with additional information that will not be //! // available in the JsonRpc request //! pub fn get_data(&self) -> &(String, i32, PhantomData<&'r ()>) { //! &self.data //! } //! //! // The `get_request` method will return the JsonRpc request to the future poll //! pub fn get_request(&self) -> Result<JrpcRequest, ErrorVariant> { //! let request = self.request.clone(); //! request //! .map(|r| Ok(r.clone())) //! .unwrap_or(Err(ErrorVariant::NoRequestProvided)) //! } //! //! // This method is of internal usage to receive the request from `JrpcHandler` //! pub fn set_request(mut self, request: JrpcRequest) -> Result<Self, ErrorVariant> { //! self.request = Some(request); //! Ok(self) //! } //! //! // This "fork" will be performed every time a new request is received, allowing async //! // processing //! pub fn clone_with_request(&self, request: JrpcRequest) -> Result<Self, ErrorVariant> { //! self.clone().set_request(request) //! } //! } //! //! // `JrpcHandler` will just return a pollable associated future. //! // //! // The main implementation will go here //! // //! // Tokio provides very good documentation on futures. Check it: https://tokio.rs/ //! impl<'r> Future for CopyParams<'r> { //! // Optimally, we want to use JrpcResponse, for it is guaranteed to respect the JSON-RPC //! // specification. But, we can change the response here to something else, if required. //! type Item = Option<JrpcResponse>; //! type Error = ErrorVariant; //! //! fn poll(&mut self) -> Result<Async<Self::Item>, Self::Error> { //! // We fetch the provided request to copy the data //! let request = self.get_request()?; //! //! // Here we can receive additional that that's not available in the request //! let (_text, _value, _) = self.get_data(); //! //! // Do something with the request //! // In this example, we are copying the parameters //! let params = request.get_params().clone().unwrap_or(JsonValue::Null); //! //! // `generate_response` will receive an enum `JrpcResponseParam` and reply //! // with either an error or success. //! let message = JrpcResponseParam::generate_result(params) //! .and_then(|result| request.generate_response(result))?; //! //! // Then, our reply is ready //! Ok(Async::Ready(Some(message))) //! } //! } //! //! // The handler will call this trait to spawn a new future and process it when a registered method //! // is requested. //! impl<'r> JrpcMethodTrait<'r> for CopyParams<'r> { //! // `generate_future` can generate any `Future` that respects the trait signature. This can be a //! // foreign structure, or just a copy of `self`, in case it implements `Future`. This can also //! // be a decision based on the received `JrpcRequest`. //! // //! // Since its not a reference, there are no restrictions. //! fn generate_future( //! &self, //! request: JrpcRequest, //! ) -> Result<Box<'r + Future<Item = Option<JrpcResponse>, Error = ErrorVariant>>, ErrorVariant> //! { //! Ok(Box::new(self.clone_with_request(request)?)) //! } //! } //! ``` #[macro_use] extern crate log; pub use crate::handler::JrpcHandler; pub use crate::method::JrpcMethodTrait; pub use crate::parser::{JrpcError, JrpcErrorEnum, JrpcRequest, JrpcResponse, JrpcResponseParam}; pub use futures; pub use serde_json::error::Error as JsonError; pub use serde_json::Value as JsonValue; use std::fmt; use std::io::Error as IoError; pub mod handler; pub mod method; pub mod parser; #[derive(Debug)] pub enum ErrorVariant { RwLockPoisoned, MethodSignatureNotFound(String), JsonParseError(JsonError), InvalidJsonRpcVersion, InvalidJsonRpcId, ResponseCannotContainResultAndError, ResponseMustContainResultOrError, NoRequestProvided, IoError(IoError), InternalError, InternalErrorMessage(String), } impl fmt::Display for ErrorVariant { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { ErrorVariant::MethodSignatureNotFound(s) => { write!(f, "Method signature '{}' not found", s) } ErrorVariant::InternalErrorMessage(s) => write!(f, "An error ocurred: {}", s), _ => write!(f, "{:?}", self), } } } #[macro_export] macro_rules! generate_method { ($struct_identifier:ident, $future:item) => { #[derive(Debug, Clone)] pub struct $struct_identifier { request: Option<JrpcRequest>, } impl $struct_identifier { pub fn new() -> Result<Self, ErrorVariant> { let request = None; let some_notification = $struct_identifier { request, }; Ok(some_notification) } pub fn get_request(&self) -> Result<JrpcRequest, ErrorVariant> { let request = self.request.clone(); request .map(|r| Ok(r.clone())) .unwrap_or(Err(ErrorVariant::NoRequestProvided)) } pub fn set_request(mut self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.request = Some(request); Ok(self) } pub fn clone_with_request(&self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.clone().set_request(request) } } $future impl<'r> JrpcMethodTrait<'r> for $struct_identifier { fn generate_future( &self, request: JrpcRequest, ) -> Result< Box<'r + Future<Item = Option<JrpcResponse>, Error = ErrorVariant>>, ErrorVariant, > { Ok(Box::new(self.clone_with_request(request)?)) } } }; } #[macro_export] macro_rules! generate_method_with_data_and_future { ($struct_identifier:ident, $data:ty, $future:item) => { #[derive(Debug, Clone)] pub struct $struct_identifier { request: Option<JrpcRequest>, data: $data, } impl $struct_identifier { pub fn new(data: $data) -> Result<Self, ErrorVariant> { let request = None; let some_notification = $struct_identifier { request, data, }; Ok(some_notification) } pub fn get_data(&self) -> &$data { &self.data } pub fn get_request(&self) -> Result<JrpcRequest, ErrorVariant> { let request = self.request.clone(); request .map(|r| Ok(r.clone())) .unwrap_or(Err(ErrorVariant::NoRequestProvided)) } pub fn set_request(mut self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.request = Some(request); Ok(self) } pub fn clone_with_request(&self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.clone().set_request(request) } } $future impl<'r> JrpcMethodTrait<'r> for $struct_identifier { fn generate_future( &self, request: JrpcRequest, ) -> Result< Box<'r + Future<Item = Option<JrpcResponse>, Error = ErrorVariant>>, ErrorVariant, > { Ok(Box::new(self.clone_with_request(request)?)) } } }; } #[macro_export] macro_rules! generate_method_with_lifetime_data_and_future { ($struct_identifier:ident, $lifetime:tt, $data:ty, $future:item) => { #[derive(Debug, Clone)] pub struct $struct_identifier<$lifetime> { request: Option<JrpcRequest>, data: $data, } impl<$lifetime> $struct_identifier<$lifetime> { pub fn new(data: $data) -> Result<Self, ErrorVariant> { let request = None; let some_notification = $struct_identifier { request, data, }; Ok(some_notification) } pub fn get_data(&self) -> &$data { &self.data } pub fn get_request(&self) -> Result<JrpcRequest, ErrorVariant> { let request = self.request.clone(); request .map(|r| Ok(r.clone())) .unwrap_or(Err(ErrorVariant::NoRequestProvided)) } pub fn set_request(mut self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.request = Some(request); Ok(self) } pub fn clone_with_request(&self, request: JrpcRequest) -> Result<Self, ErrorVariant> { self.clone().set_request(request) } } $future impl<$lifetime> JrpcMethodTrait<$lifetime> for $struct_identifier<$lifetime> { fn generate_future( &self, request: JrpcRequest, ) -> Result< Box<$lifetime + Future<Item = Option<JrpcResponse>, Error = ErrorVariant>>, ErrorVariant, > { Ok(Box::new(self.clone_with_request(request)?)) } } }; }