bitconch_jsonrpc_core/
middleware.rs

1//! `IoHandler` middlewares
2
3use calls::Metadata;
4use types::{Request, Response};
5use futures::{future::Either, Future};
6
7/// RPC middleware
8pub trait Middleware<M: Metadata>: Send + Sync + 'static {
9	/// A returned future.
10	type Future: Future<Item=Option<Response>, Error=()> + Send + 'static;
11
12	/// Method invoked on each request.
13	/// Allows you to either respond directly (without executing RPC call)
14	/// or do any additional work before and/or after processing the request.
15	fn on_request<F, X>(&self, request: Request, meta: M, next: F) -> Either<Self::Future, X> where
16		F: FnOnce(Request, M) -> X + Send,
17		X: Future<Item=Option<Response>, Error=()> + Send + 'static;
18}
19
20/// No-op middleware implementation
21#[derive(Debug, Default)]
22pub struct Noop;
23impl<M: Metadata> Middleware<M> for Noop {
24	type Future = Box<Future<Item=Option<Response>, Error=()> + Send>;
25
26	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Either<Self::Future, X> where
27		F: FnOnce(Request, M) -> X + Send,
28		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
29	{
30		Either::B(process(request, meta))
31	}
32}
33
34impl<M: Metadata, A: Middleware<M>, B: Middleware<M>>
35	Middleware<M> for (A, B)
36{
37	type Future = Either<A::Future, B::Future>;
38
39	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Either<Self::Future, X> where
40		F: FnOnce(Request, M) -> X + Send,
41		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
42	{
43		repack(self.0.on_request(request, meta, move |request, meta| {
44			self.1.on_request(request, meta, process)
45		}))
46	}
47}
48
49impl<M: Metadata, A: Middleware<M>, B: Middleware<M>, C: Middleware<M>>
50	Middleware<M> for (A, B, C)
51{
52	type Future = Either<A::Future, Either<B::Future, C::Future>>;
53
54	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Either<Self::Future, X> where
55		F: FnOnce(Request, M) -> X + Send,
56		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
57	{
58		repack(self.0.on_request(request, meta, move |request, meta| {
59			repack(self.1.on_request(request, meta, move |request, meta| {
60				self.2.on_request(request, meta, process)
61			}))
62		}))
63	}
64}
65
66impl<M: Metadata, A: Middleware<M>, B: Middleware<M>, C: Middleware<M>, D: Middleware<M>>
67	Middleware<M> for (A, B, C, D)
68{
69	type Future = Either<A::Future, Either<B::Future, Either<C::Future, D::Future>>>;
70
71	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Either<Self::Future, X> where
72		F: FnOnce(Request, M) -> X + Send,
73		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
74	{
75		repack(self.0.on_request(request, meta, move |request, meta| {
76			repack(self.1.on_request(request, meta, move |request, meta| {
77				repack(self.2.on_request(request, meta, move |request, meta| {
78					self.3.on_request(request, meta, process)
79				}))
80			}))
81		}))
82	}
83}
84
85#[inline(always)]
86fn repack<A, B, X>(result: Either<A, Either<B, X>>) -> Either<Either<A, B>, X> {
87	match result {
88		Either::A(a) => Either::A(Either::A(a)),
89		Either::B(Either::A(b)) => Either::A(Either::B(b)),
90		Either::B(Either::B(x)) => Either::B(x),
91	}
92}
bitconch_jsonrpc_core/middleware.rs

bitconch_jsonrpc_core/
middleware.rs
