simple_proxy 1.3.4

Simple proxy with middlewares, easy to customize, easy to use.
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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181

use futures::future;
use futures::future::TryFutureExt;
use hyper::client::connect::HttpConnector;
use hyper::service::Service;
use hyper::{Body, Client, Request, Response};
use std::future::Future;

use std::collections::HashMap;
use std::net::SocketAddr;
use std::{
    pin::Pin,
    sync::{Arc, Mutex},
    task::{Context, Poll},
};

use rand::prelude::*;
use rand::rngs::SmallRng;

use crate::proxy::middleware::MiddlewareResult::*;
use crate::Middlewares;

// type BoxFut = Box<dyn Future<Output = Result<hyper::Response<Body>, hyper::Error>> + Send>;
pub type State = Arc<Mutex<HashMap<(String, u64), String>>>;

pub struct ProxyService {
    client: Client<HttpConnector>,
    middlewares: Middlewares,
    state: State,
    remote_addr: SocketAddr,
    rng: SmallRng,
}

#[derive(Clone, Copy)]
pub struct ServiceContext {
    pub remote_addr: SocketAddr,
    pub req_id: u64,
}

impl Service<Request<hyper::Body>> for ProxyService {
    type Response = Response<hyper::Body>;
    type Error = hyper::Error;
    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        match self.client.poll_ready(cx) {
            Poll::Ready(Ok(())) => Poll::Ready(Ok(())),
            Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
            Poll::Pending => Poll::Pending,
        }
    }

    fn call(&mut self, req: Request<hyper::Body>) -> Self::Future {
        self.clear_state();
        let (parts, body) = req.into_parts();
        let mut req = Request::from_parts(parts, body);

        // Create references for future callbacks
        // references are moved in each chained future (map,then..)
        let mws_failure = Arc::clone(&self.middlewares);
        let mws_success = Arc::clone(&self.middlewares);
        let mws_after_success = Arc::clone(&self.middlewares);
        let mws_after_failure = Arc::clone(&self.middlewares);
        let state_failure = Arc::clone(&self.state);
        let state_success = Arc::clone(&self.state);
        let state_after_success = Arc::clone(&self.state);
        let state_after_failure = Arc::clone(&self.state);

        let req_id = self.rng.next_u64();

        let context = ServiceContext {
            req_id,
            remote_addr: self.remote_addr,
        };

        let mut before_res: Option<Response<Body>> = None;
        for mw in self.middlewares.lock().unwrap().iter_mut() {
            // Run all middlewares->before_request
            if let Some(res) = match mw.before_request(&mut req, &context, &self.state) {
                Err(err) => Some(Response::from(err)),
                Ok(RespondWith(response)) => Some(response),
                Ok(Next) => None,
            } {
                // Stop when an early response is wanted
                before_res = Some(res);
                break;
            }
        }

        if let Some(res) = before_res {
            return Box::pin(future::ok(self.early_response(&context, res, &self.state)));
        }

        let res = self
            .client
            .request(req)
            .map_err(move |err| {
                for mw in mws_failure.lock().unwrap().iter_mut() {
                    // TODO: think about graceful handling
                    if let Err(err) = mw.request_failure(&err, &context, &state_failure) {
                        error!("Request_failure errored: {:?}", &err);
                    }
                }
                err
            })
            .map_ok(move |mut res| {
                for mw in mws_success.lock().unwrap().iter_mut() {
                    match mw.request_success(&mut res, &context, &state_success) {
                        Err(err) => res = Response::from(err),
                        Ok(RespondWith(response)) => res = response,
                        Ok(Next) => (),
                    }
                }
                res
            })
            .map_ok_or_else(
                move |err| {
                    let mut res = Err(err);
                    for mw in mws_after_success.lock().unwrap().iter_mut() {
                        match mw.after_request(None, &context, &state_after_success) {
                            Err(err) => res = Ok(Response::from(err)),
                            Ok(RespondWith(response)) => res = Ok(response),
                            Ok(Next) => (),
                        }
                    }
                    res
                },
                move |mut res| {
                    for mw in mws_after_failure.lock().unwrap().iter_mut() {
                        match mw.after_request(Some(&mut res), &context, &state_after_failure) {
                            Err(err) => res = Response::from(err),
                            Ok(RespondWith(response)) => res = response,
                            Ok(Next) => (),
                        }
                    }
                    Ok(res)
                },
            );

        Box::pin(res)
    }
}

impl ProxyService {
    fn early_response(
        &self,
        context: &ServiceContext,
        mut res: Response<Body>,
        state: &State,
    ) -> Response<Body> {
        for mw in self.middlewares.lock().unwrap().iter_mut() {
            match mw.after_request(Some(&mut res), context, state) {
                Err(err) => res = Response::from(err),
                Ok(RespondWith(response)) => res = response,
                Ok(Next) => (),
            }
        }
        debug!("Early response is {:?}", &res);
        res
    }

    // Needed to avoid a single connection creating too much data in state
    // Since we need to identify each request in state (HashMap tuple identifier), it grows
    // for each request from the same connection
    fn clear_state(&self) {
        if let Ok(mut state) = self.state.lock() {
            state.clear();
        } else {
            error!("[FATAL] Cannot lock state in clean_stale_state");
        }
    }

    pub fn new(middlewares: Middlewares, remote_addr: SocketAddr) -> Self {
        ProxyService {
            client: Client::new(),
            state: Arc::new(Mutex::new(HashMap::new())),
            rng: SmallRng::from_entropy(),
            remote_addr,
            middlewares,
        }
    }
}