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
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212

use std::{
    convert::Infallible,
    io::Write,
    net::{IpAddr, SocketAddr},
};

use crate::{
    model::Update,
    utils::result::{Result as TelegramResult, TelegramError},
};
use hyper::{
    body::HttpBody,
    service::{make_service_fn, service_fn},
    Body,
    Method,
    Request,
    Response,
    Server,
    StatusCode,
    Uri,
};
use tokio::sync::mpsc::{channel, Receiver, Sender};

/// Handles listening to the telegram webhook and will provide you with the
/// incoming updates
#[derive(Debug)]
pub struct Webhook {
    opts: WebhookOptions,
}

impl Webhook {
    /// creates a new `Webhook` based on the provided `WebhookOptions`
    pub fn new(opts: &WebhookOptions) -> Self {
        Self {
            opts: opts.clone(),
        }
    }

    /// starts the webhandling and returns a [`Receiver`], which will allow you
    /// to receive the incoming updates
    pub fn start(self) -> Receiver<TelegramResult<Update>> {
        let (tx, rx) = channel(1000);

        tokio::spawn(start_ws(self.opts, tx));
        rx
    }
}

async fn handle_update(
    payload: HandlingPayload,
    req: Request<Body>,
) -> TelegramResult<Response<Body>> {
    let mut response = Response::new(Body::empty());

    let mut raw_body = req.into_body();
    let mut body: Vec<u8> = Vec::new();
    while let Some(chunk) = raw_body.data().await {
        body.write_all(&chunk?)?;
    }

    let update: Update = serde_json::from_slice(&body)?;
    let send_res = payload.chan.send(Ok(update)).await;
    if send_res.is_err() {
        return Err(TelegramError::WebhookError.into());
    }

    *response.status_mut() = StatusCode::OK;
    Ok(response)
}

async fn handle_req(
    payload: HandlingPayload,
    req: Request<Body>,
) -> Result<Response<Body>, Infallible> {
    let mut response = Response::new(Body::empty());

    match (req.method(), req.uri().path()) {
        (&Method::POST, path) if path == payload.path => {
            let result = handle_update(payload, req).await;

            if result.is_err() {
                *response.status_mut() = StatusCode::INTERNAL_SERVER_ERROR;
            } else {
                response = result.unwrap();
            }
        },
        _ => {
            *response.status_mut() = StatusCode::NOT_FOUND;
        },
    }

    Ok(response)
}

async fn start_ws(
    opts: WebhookOptions,
    chan: Sender<TelegramResult<Update>>,
) -> TelegramResult<()> {
    let addr = SocketAddr::from((opts.ip, opts.port));

    let payload = HandlingPayload::new(&opts, chan.clone());
    let make_svc = make_service_fn(move |_conn| {
        let inner_payload = payload.clone();
        async move {
            Ok::<_, Infallible>(service_fn(move |req| {
                handle_req(inner_payload.clone(), req)
            }))
        }
    });

    let server = Server::bind(&addr).serve(make_svc);
    let graceful = server.with_graceful_shutdown(shutdown_signal());

    if let Err(e) = graceful.await {
        let send_res = chan
            .send(Err(TelegramError::Unknown(e.to_string()).into()))
            .await;
        if send_res.is_err() {
            return Err(TelegramError::WebhookError.into());
        }
    }
    Ok(())
}

async fn shutdown_signal() {
    // Wait for the CTRL+C signal
    tokio::signal::ctrl_c()
        .await
        .expect("failed to install CTRL+C signal handler");
}

/// Represents the options to set for the webhook handling
#[derive(Clone, Debug)]
pub struct WebhookOptions {
    pub url: Option<Uri>,
    pub path: String,
    pub port: u16,
    pub ip: IpAddr,
    pub secret_token: Option<String>,
}

impl WebhookOptions {
    /// Creates a new `WebhookOptions` with default values
    ///
    /// By default it will listen on 127.0.0.1:8006 and the path being the root
    pub fn new() -> Self {
        Self {
            url: None,
            path: "/".to_owned(),
            port: 8006,
            ip: [127, 0, 0, 1].into(),
            secret_token: None,
        }
    }

    /// Sets the path of the webhook
    pub fn set_path(&mut self, path: &str) -> &mut Self {
        self.path = path.to_owned();
        self
    }

    /// Sets the port the webhook will be listening on
    pub fn set_port(&mut self, port: u16) -> &mut Self {
        self.port = port;
        self
    }

    /// Sets the IP the webhook will be listening on
    pub fn set_ip<T: Into<IpAddr>>(&mut self, ip: T) -> &mut Self {
        self.ip = ip.into();
        self
    }

    /// Sets the url of the webhook
    pub fn set_url(&mut self, url: &str) -> TelegramResult<&mut Self> {
        self.url = Some(url.parse()?);
        Ok(self)
    }

    /// Sets the secret token of the webhook
    pub fn set_secret_token(&mut self, secret_token: &impl ToString) -> TelegramResult<&mut Self> {
        self.secret_token = Some(secret_token.to_string());
        Ok(self)
    }

    fn get_path(&self) -> &str {
        self.url
            .as_ref()
            .map_or_else(|| self.path.as_str(), |url| url.path())
    }
}

impl Default for WebhookOptions {
    fn default() -> Self {
        Self::new()
    }
}

#[derive(Clone, Debug)]
struct HandlingPayload {
    path: String,
    chan: Sender<TelegramResult<Update>>,
}

impl HandlingPayload {
    fn new(opts: &WebhookOptions, sender: Sender<TelegramResult<Update>>) -> Self {
        Self {
            path: opts.get_path().to_owned(),
            chan: sender,
        }
    }
}