ethrpc 0.0.8

Ethereum transport-agnositic JSON RPC implementation
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

//! Buffered Ethereum JSON RPC HTTP client.
//!
//! Concurrent JSON RPC calls will be automatically buffered and executed as a
//! single JSON RPC batch call.

use super::client::{Client, Error};
use crate::{jsonrpc, method::Method, types::Empty};
use futures::{
    channel::{mpsc, oneshot},
    stream::StreamExt as _,
};
use serde::Serialize;
use std::{num::NonZeroUsize, sync::Arc, time::Duration};
use tokio_stream::StreamExt as _;

/// A buffered JSON RPC HTTP client.
pub struct Buffered {
    client: Arc<Client>,
    calls: mpsc::UnboundedSender<Call>,
}

struct Call {
    request: jsonrpc::Request,
    response: oneshot::Sender<Result<jsonrpc::Response, Error>>,
}

impl Client {
    /// Returns a [`Buffered`] HTTP JSON RPC client.
    pub fn buffered(self, config: Configuration) -> Buffered {
        let client = Arc::new(self);
        let (calls, receiver) = mpsc::unbounded();

        tokio::task::spawn(Buffered::background_worker(
            client.clone(),
            receiver,
            config,
        ));

        Buffered { client, calls }
    }
}

impl Buffered {
    /// Creates a new JSON RPC HTTP client for the specified client instance and
    /// URL.
    pub fn client(&self) -> &Client {
        &self.client
    }

    async fn background_worker(
        client: Arc<Client>,
        calls: mpsc::UnboundedReceiver<Call>,
        config: Configuration,
    ) {
        calls
            .chunks_timeout(config.max_size, config.delay)
            .for_each_concurrent(
                config.max_concurrent_requests.map(NonZeroUsize::get),
                |mut chunk| {
                    let client = client.clone();
                    async move {
                        match chunk.len() {
                            0 => (),
                            1 => {
                                let call = chunk.remove(0);
                                let response = client.roundtrip(call.request).await;
                                let _ = call.response.send(response);
                            }
                            n => {
                                let (requests, channels): (Vec<_>, Vec<_>) = chunk
                                    .into_iter()
                                    .map(|call| (call.request, call.response))
                                    .unzip();
                                let responses = client
                                    .roundtrip::<_, Vec<jsonrpc::Response>>(requests)
                                    .await
                                    .map(|responses| {
                                        responses.into_iter().map(Ok).collect::<Vec<_>>()
                                    })
                                    .unwrap_or_else(|err| {
                                        (0..n).map(|_| Err(err.duplicate())).collect()
                                    });
                                for (channel, response) in channels.into_iter().zip(responses) {
                                    let _ = channel.send(response);
                                }
                            }
                        }
                    }
                },
            )
            .await;
    }

    async fn roundtrip(&self, request: jsonrpc::Request) -> Result<jsonrpc::Response, Error> {
        async {
            let (sender, receiver) = oneshot::channel();
            self.calls
                .unbounded_send(Call {
                    request,
                    response: sender,
                })
                .ok()?;
            receiver.await.ok()
        }
        .await
        .expect("background worker unexpectedly stopped")
    }

    /// Executes a JSON RPC call.
    pub async fn call<M>(&self, method: M, params: M::Params) -> Result<M::Result, Error>
    where
        M: Method + Serialize,
    {
        jsonrpc::call_async(method, params, |request| self.roundtrip(request)).await
    }

    /// Executes a JSON RPC call with no parameters.
    pub async fn call_np<M>(&self, method: M) -> Result<M::Result, Error>
    where
        M: Method<Params = Empty> + Serialize,
    {
        jsonrpc::call_async(method, Empty, |request| self.roundtrip(request)).await
    }
}

/// Buffered JSON RPC configuration.
pub struct Configuration {
    /// The maximum amount of concurrent batches to send to the node.
    ///
    /// Specifying `None` means no limit on concurrency.
    pub max_concurrent_requests: Option<NonZeroUsize>,
    /// The maximum batch size.
    pub max_size: usize,
    /// An additional minimum delay to wait for collecting requests.
    ///
    /// The delay starts counting after receiving the first request.
    pub delay: Duration,
}

impl Default for Configuration {
    fn default() -> Self {
        Self {
            max_concurrent_requests: NonZeroUsize::new(1),
            max_size: 20,
            delay: Duration::default(),
        }
    }
}