librespot_core/
http_client.rs

1use std::{
2    sync::OnceLock,
3    time::{Duration, Instant},
4};
5
6use bytes::Bytes;
7use futures_util::{FutureExt, future::IntoStream};
8use governor::{
9    Quota, RateLimiter, clock::MonotonicClock, middleware::NoOpMiddleware,
10    state::keyed::DefaultKeyedStateStore,
11};
12use http::{Uri, header::HeaderValue};
13use http_body_util::{BodyExt, Full};
14use hyper::{HeaderMap, Request, Response, StatusCode, body::Incoming, header::USER_AGENT};
15use hyper_proxy2::{Intercept, Proxy, ProxyConnector};
16use hyper_util::{
17    client::legacy::{Client, ResponseFuture, connect::HttpConnector},
18    rt::TokioExecutor,
19};
20use nonzero_ext::nonzero;
21use thiserror::Error;
22use url::Url;
23
24#[cfg(all(feature = "__rustls", not(feature = "native-tls")))]
25use hyper_rustls::{HttpsConnector, HttpsConnectorBuilder};
26#[cfg(all(feature = "native-tls", not(feature = "__rustls")))]
27use hyper_tls::HttpsConnector;
28
29use crate::{
30    Error,
31    config::{OS, os_version},
32    date::Date,
33    version::{FALLBACK_USER_AGENT, VERSION_STRING, spotify_version},
34};
35
36// The 30 seconds interval is documented by Spotify, but the calls per interval
37// is a guesstimate and probably subject to licensing (purchasing extra calls)
38// and may change at any time.
39pub const RATE_LIMIT_INTERVAL: Duration = Duration::from_secs(30);
40pub const RATE_LIMIT_MAX_WAIT: Duration = Duration::from_secs(10);
41pub const RATE_LIMIT_CALLS_PER_INTERVAL: u32 = 300;
42
43#[derive(Debug, Error)]
44pub enum HttpClientError {
45    #[error("Response status code: {0}")]
46    StatusCode(hyper::StatusCode),
47}
48
49impl From<HttpClientError> for Error {
50    fn from(err: HttpClientError) -> Self {
51        match err {
52            HttpClientError::StatusCode(code) => {
53                // not exhaustive, but what reasonably could be expected
54                match code {
55                    StatusCode::GATEWAY_TIMEOUT | StatusCode::REQUEST_TIMEOUT => {
56                        Error::deadline_exceeded(err)
57                    }
58                    StatusCode::GONE
59                    | StatusCode::NOT_FOUND
60                    | StatusCode::MOVED_PERMANENTLY
61                    | StatusCode::PERMANENT_REDIRECT
62                    | StatusCode::TEMPORARY_REDIRECT => Error::not_found(err),
63                    StatusCode::FORBIDDEN | StatusCode::PAYMENT_REQUIRED => {
64                        Error::permission_denied(err)
65                    }
66                    StatusCode::NETWORK_AUTHENTICATION_REQUIRED
67                    | StatusCode::PROXY_AUTHENTICATION_REQUIRED
68                    | StatusCode::UNAUTHORIZED => Error::unauthenticated(err),
69                    StatusCode::EXPECTATION_FAILED
70                    | StatusCode::PRECONDITION_FAILED
71                    | StatusCode::PRECONDITION_REQUIRED => Error::failed_precondition(err),
72                    StatusCode::RANGE_NOT_SATISFIABLE => Error::out_of_range(err),
73                    StatusCode::INTERNAL_SERVER_ERROR
74                    | StatusCode::MISDIRECTED_REQUEST
75                    | StatusCode::SERVICE_UNAVAILABLE
76                    | StatusCode::UNAVAILABLE_FOR_LEGAL_REASONS => Error::unavailable(err),
77                    StatusCode::BAD_REQUEST
78                    | StatusCode::HTTP_VERSION_NOT_SUPPORTED
79                    | StatusCode::LENGTH_REQUIRED
80                    | StatusCode::METHOD_NOT_ALLOWED
81                    | StatusCode::NOT_ACCEPTABLE
82                    | StatusCode::PAYLOAD_TOO_LARGE
83                    | StatusCode::REQUEST_HEADER_FIELDS_TOO_LARGE
84                    | StatusCode::UNSUPPORTED_MEDIA_TYPE
85                    | StatusCode::URI_TOO_LONG => Error::invalid_argument(err),
86                    StatusCode::TOO_MANY_REQUESTS => Error::resource_exhausted(err),
87                    StatusCode::NOT_IMPLEMENTED => Error::unimplemented(err),
88                    _ => Error::unknown(err),
89                }
90            }
91        }
92    }
93}
94
95type HyperClient = Client<ProxyConnector<HttpsConnector<HttpConnector>>, Full<bytes::Bytes>>;
96
97pub struct HttpClient {
98    user_agent: HeaderValue,
99    proxy_url: Option<Url>,
100    hyper_client: OnceLock<HyperClient>,
101
102    rate_limiter:
103        RateLimiter<String, DefaultKeyedStateStore<String>, MonotonicClock, NoOpMiddleware>,
104}
105
106impl HttpClient {
107    pub fn new(proxy_url: Option<&Url>) -> Self {
108        let zero_str = String::from("0");
109        let os_version = os_version();
110
111        let (spotify_platform, os_version) = match OS {
112            "android" => ("Android", os_version),
113            "ios" => ("iOS", os_version),
114            "macos" => ("OSX", zero_str),
115            "windows" => ("Win32", zero_str),
116            _ => ("Linux", zero_str),
117        };
118
119        let user_agent_str = &format!(
120            "Spotify/{} {}/{} ({})",
121            spotify_version(),
122            spotify_platform,
123            os_version,
124            VERSION_STRING
125        );
126
127        let user_agent = HeaderValue::from_str(user_agent_str).unwrap_or_else(|err| {
128            error!("Invalid user agent <{user_agent_str}>: {err}");
129            HeaderValue::from_static(FALLBACK_USER_AGENT)
130        });
131
132        let replenish_interval_ns =
133            RATE_LIMIT_INTERVAL.as_nanos() / RATE_LIMIT_CALLS_PER_INTERVAL as u128;
134        let quota = Quota::with_period(Duration::from_nanos(replenish_interval_ns as u64))
135            .expect("replenish interval should be valid")
136            .allow_burst(nonzero![RATE_LIMIT_CALLS_PER_INTERVAL]);
137        let rate_limiter = RateLimiter::keyed(quota);
138
139        Self {
140            user_agent,
141            proxy_url: proxy_url.cloned(),
142            hyper_client: OnceLock::new(),
143            rate_limiter,
144        }
145    }
146
147    fn try_create_hyper_client(proxy_url: Option<&Url>) -> Result<HyperClient, Error> {
148        // configuring TLS is expensive and should be done once per process
149
150        #[cfg(all(feature = "__rustls", not(feature = "native-tls")))]
151        let https_connector = {
152            #[cfg(feature = "rustls-tls-native-roots")]
153            let tls = HttpsConnectorBuilder::new().with_native_roots()?;
154            #[cfg(feature = "rustls-tls-webpki-roots")]
155            let tls = HttpsConnectorBuilder::new().with_webpki_roots();
156            tls.https_or_http().enable_http1().enable_http2().build()
157        };
158
159        #[cfg(all(feature = "native-tls", not(feature = "__rustls")))]
160        let https_connector = HttpsConnector::new();
161
162        // When not using a proxy a dummy proxy is configured that will not intercept any traffic.
163        // This prevents needing to carry the Client Connector generics through the whole project
164        let proxy = match &proxy_url {
165            Some(proxy_url) => Proxy::new(Intercept::All, proxy_url.to_string().parse()?),
166            None => Proxy::new(Intercept::None, Uri::from_static("0.0.0.0")),
167        };
168        let proxy_connector = ProxyConnector::from_proxy(https_connector, proxy)?;
169
170        let client = Client::builder(TokioExecutor::new())
171            .http2_adaptive_window(true)
172            .build(proxy_connector);
173        Ok(client)
174    }
175
176    fn hyper_client(&self) -> &HyperClient {
177        self.hyper_client
178            .get_or_init(|| Self::try_create_hyper_client(self.proxy_url.as_ref()).unwrap())
179    }
180
181    pub async fn request(&self, req: Request<Bytes>) -> Result<Response<Incoming>, Error> {
182        debug!("Requesting {}", req.uri());
183
184        // `Request` does not implement `Clone` because its `Body` may be a single-shot stream.
185        // As correct as that may be technically, we now need all this boilerplate to clone it
186        // ourselves, as any `Request` is moved in the loop.
187        let (parts, body_as_bytes) = req.into_parts();
188
189        loop {
190            let mut req = Request::builder()
191                .method(parts.method.clone())
192                .uri(parts.uri.clone())
193                .version(parts.version)
194                .body(body_as_bytes.clone())?;
195            *req.headers_mut() = parts.headers.clone();
196
197            let request = self.request_fut(req)?;
198            let response = request.await;
199
200            if let Ok(response) = &response {
201                let code = response.status();
202
203                if code == StatusCode::TOO_MANY_REQUESTS {
204                    if let Some(duration) = Self::get_retry_after(response.headers()) {
205                        warn!(
206                            "Rate limited by service, retrying in {} seconds...",
207                            duration.as_secs()
208                        );
209                        tokio::time::sleep(duration).await;
210                        continue;
211                    }
212                }
213
214                if !code.is_success() {
215                    return Err(HttpClientError::StatusCode(code).into());
216                }
217            }
218
219            let response = response?;
220            return Ok(response);
221        }
222    }
223
224    pub async fn request_body(&self, req: Request<Bytes>) -> Result<Bytes, Error> {
225        let response = self.request(req).await?;
226        Ok(response.into_body().collect().await?.to_bytes())
227    }
228
229    pub fn request_stream(&self, req: Request<Bytes>) -> Result<IntoStream<ResponseFuture>, Error> {
230        Ok(self.request_fut(req)?.into_stream())
231    }
232
233    pub fn request_fut(&self, mut req: Request<Bytes>) -> Result<ResponseFuture, Error> {
234        let headers_mut = req.headers_mut();
235        headers_mut.insert(USER_AGENT, self.user_agent.clone());
236
237        // For rate limiting we cannot *just* depend on Spotify sending us HTTP/429
238        // Retry-After headers. For example, when there is a service interruption
239        // and HTTP/500 is returned, we don't want to DoS the Spotify infrastructure.
240        let domain = match req.uri().host() {
241            Some(host) => {
242                // strip the prefix from *.domain.tld (assume rate limit is per domain, not subdomain)
243                let mut parts = host
244                    .split('.')
245                    .map(|s| s.to_string())
246                    .collect::<Vec<String>>();
247                let n = parts.len().saturating_sub(2);
248                parts.drain(n..).collect()
249            }
250            None => String::from(""),
251        };
252        self.rate_limiter.check_key(&domain).map_err(|e| {
253            Error::resource_exhausted(format!(
254                "rate limited for at least another {} seconds",
255                e.wait_time_from(Instant::now()).as_secs()
256            ))
257        })?;
258
259        Ok(self.hyper_client().request(req.map(Full::new)))
260    }
261
262    pub fn get_retry_after(headers: &HeaderMap<HeaderValue>) -> Option<Duration> {
263        let now = Date::now_utc().as_timestamp_ms();
264
265        let mut retry_after_ms = None;
266        if let Some(header_val) = headers.get("X-RateLimit-Next") {
267            // *.akamaized.net (Akamai)
268            if let Ok(date_str) = header_val.to_str() {
269                if let Ok(target) = Date::from_iso8601(date_str) {
270                    retry_after_ms = Some(target.as_timestamp_ms().saturating_sub(now))
271                }
272            }
273        } else if let Some(header_val) = headers.get("Fastly-RateLimit-Reset") {
274            // *.scdn.co (Fastly)
275            if let Ok(timestamp) = header_val.to_str() {
276                if let Ok(target) = timestamp.parse::<i64>() {
277                    retry_after_ms = Some(target.saturating_sub(now))
278                }
279            }
280        } else if let Some(header_val) = headers.get("Retry-After") {
281            // Generic RFC compliant (including *.spotify.com)
282            if let Ok(retry_after) = header_val.to_str() {
283                if let Ok(duration) = retry_after.parse::<i64>() {
284                    retry_after_ms = Some(duration * 1000)
285                }
286            }
287        }
288
289        if let Some(retry_after) = retry_after_ms {
290            let duration = Duration::from_millis(retry_after as u64);
291            if duration <= RATE_LIMIT_MAX_WAIT {
292                return Some(duration);
293            } else {
294                debug!(
295                    "Waiting {} seconds would exceed {} second limit",
296                    duration.as_secs(),
297                    RATE_LIMIT_MAX_WAIT.as_secs()
298                );
299            }
300        }
301
302        None
303    }
304}
librespot_core/http_client.rs

librespot_core/
http_client.rs
