rs_jsonrpc_core/
middleware.rs

1//! `IoHandler` middlewares
2
3use calls::Metadata;
4use types::{Request, Response};
5use futures::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) -> Self::Future 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) -> Self::Future where
27		F: FnOnce(Request, M) -> X + Send,
28		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
29	{
30		Box::new(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 = A::Future;
38
39	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Self::Future where
40		F: FnOnce(Request, M) -> X + Send,
41		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
42	{
43		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 = A::Future;
53
54	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Self::Future where
55		F: FnOnce(Request, M) -> X + Send,
56		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
57	{
58		self.0.on_request(request, meta, move |request, meta| {
59			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 = A::Future;
70
71	fn on_request<F, X>(&self, request: Request, meta: M, process: F) -> Self::Future where
72		F: FnOnce(Request, M) -> X + Send,
73		X: Future<Item=Option<Response>, Error=()> + Send + 'static,
74	{
75		self.0.on_request(request, meta, move |request, meta| {
76			self.1.on_request(request, meta, move |request, meta| {
77				self.2.on_request(request, meta, move |request, meta| {
78					self.3.on_request(request, meta, process)
79				})
80			})
81		})
82	}
83}
rs_jsonrpc_core/middleware.rs

rs_jsonrpc_core/
middleware.rs
