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
use std::{
io::{self, Read, Write},
net, num,
panic::{catch_unwind, AssertUnwindSafe},
rc::Rc,
sync::Arc,
};
use rayon::ThreadPoolBuilder;
use crate::{
http::{
handler::{trigger, Handler},
request::Request,
response::IntoResponse,
StatusCode,
},
middleware::MiddlewareHandler,
router::Router,
};
/// Encapsulates functionality to serve HTTP requests.
pub struct Server {
listener: net::TcpListener,
num_threads: Option<usize>,
global_middleware: Vec<MiddlewareHandler>,
router: Router,
}
type ChainOperator = Rc<Box<dyn Fn(Request) -> Box<dyn IntoResponse>>>;
impl Server {
/// Binds the server to the provided address.
///
/// ```
/// use snx::{Server, router::Router};
///
/// let router = Router::builder().build().unwrap();
/// let global_middleware = vec![];
/// let server = Server::try_bind("127.0.0.1:2002", router, global_middleware).expect("failed to bind listener");
/// ```
pub fn try_bind(
addr: impl net::ToSocketAddrs,
router: Router,
global_middleware: Vec<MiddlewareHandler>,
) -> io::Result<Self> {
let listener = net::TcpListener::bind(addr)?;
Ok(Self {
listener,
num_threads: None,
router,
global_middleware,
})
}
/// Starts serving incoming HTTP requests.
///
/// ```no_run
/// use snx::{Server, router::Router};
///
/// let router = Router::builder().build().unwrap();
/// Server::try_bind("127.0.0.1:2002", router, vec![])
/// .expect("failed to bind to listener")
/// .serve();
/// ```
pub fn serve(self) {
let num_threads = self.num_threads.unwrap_or(
std::thread::available_parallelism()
.map(num::NonZero::get)
.unwrap_or(4),
);
let pool = ThreadPoolBuilder::new()
.num_threads(num_threads)
.build()
.unwrap();
for connection in self.listener.incoming() {
match connection {
Ok(stream) => pool.install(|| self.handle_connection(stream)),
Err(e) => tracing::info!("client failed to connect: {e}"),
}
}
}
/// Sets the number of threads to be used in the threadpool.
///
/// ```
/// use snx::{Server, router::Router};
///
/// let router = Router::builder().build().unwrap();
/// let server = Server::try_bind("127.0.0.1:2002", router, vec![])
/// .expect("failed to bind to listener")
/// .num_threads(4);
/// ```
pub fn num_threads(mut self, amount: usize) -> Self {
self.num_threads = Some(amount);
self
}
/// Handles an incoming connection.
///
/// Reads data from the stream, parses it into a [Request], dispatches it to the router,
/// executes the associated handler and writes a response back to the stream.
fn handle_connection(&self, mut stream: net::TcpStream) {
let mut buffer = [0; 8192];
match stream.read(&mut buffer) {
Ok(bytes_read) => {
if bytes_read == 0 {
return;
}
let into_response: Box<dyn IntoResponse> =
match Request::try_parse_from_bytes(&buffer, stream.peer_addr().ok()) {
Ok(mut request) => match self.router.dispatch(&mut request) {
Ok(route) => self.execute(route.handler(), route.middleware(), request),
Err(_) => self.execute(
Arc::new(Box::new(|_| StatusCode::NotFound)),
vec![],
request,
),
},
Err(e) => {
tracing::warn!("could not parse request: {e}");
Box::new(StatusCode::BadRequest)
}
};
let _ = stream.write_all(
&into_response
.into_response()
.serialize_to_raw_http_response(),
);
}
Err(e) => tracing::warn!("could not read from client: {e}"),
}
}
/// Executes the given handler with the given middleware.
fn execute(
&self,
handler: Arc<Box<dyn Handler + Send + Sync>>,
middleware: Vec<MiddlewareHandler>,
request: Request,
) -> Box<dyn IntoResponse> {
let mut middleware = middleware.clone();
let mut chain: Vec<ChainOperator> = Vec::with_capacity(middleware.len() + 1);
// first, add the actual handler call to the chain (this will be called last)
chain.push(Rc::new(Box::new(move |request: Request| {
catch_unwind(AssertUnwindSafe(|| {
trigger(request.clone(), handler.clone())
}))
.unwrap_or(Box::new(StatusCode::InternalServerError))
})));
// second, loop over all middleware for route (and global middleware) and add in reverse
// order.
middleware.extend_from_slice(&self.global_middleware);
for handler in middleware {
let op = chain.last().unwrap().clone();
chain.push(Rc::new(Box::new(move |request: Request| {
(handler)(
request.clone(),
Box::new({
let value = op.clone();
move || value(request.clone()).into_response()
}),
)
})));
}
// last, kick off the chain by calling the end of it (the outermost middleware)
chain.last().unwrap()(request)
}
}