feat: implement Qobuz CMAF streaming and AES decryption

Introduces a new CMAF streaming module for Qobuz that handles progressive segment fetching and full-track decryption. The implementation adds HKDF session key derivation, AES-128-CBC key unwrapping, and AES-128-CTR frame decryption, alongside an ISO BMFF parser for extracting FLAC headers and segment metadata. It also integrates automatic session renewal with double-checked locking, a generic async retry mechanism for transient HTTP errors, and centralized error handling. Finally, it exposes `CmafStreamInfo` and async streaming methods in the public API, updating cryptographic dependencies accordingly.

pmoqobuz/src/api/cmaf.rs

@@ -0,0 +1,261 @@
+//! Endpoints API CMAF de Qobuz : session/start et file/url.
+//!
+//! Ces endpoints implémentent le nouveau pipeline de streaming Qobuz
+//! qui remplace progressivement `/track/getFileUrl`.
+
+use serde::Deserialize;
+use std::time::{SystemTime, UNIX_EPOCH};
+use tokio::sync::RwLock;
+use tracing::info;
+
+use crate::cmaf::crypto::{compute_request_sig, CMAF_SEED};
+use crate::error::{QobuzError, Result};
+
+/// État d'une session CMAF active.
+pub struct CmafSession {
+    pub session_id: String,
+    pub infos: String,
+    pub expires_at: u64,
+}
+
+/// Réponse de l'endpoint /session/start.
+#[derive(Debug, Deserialize)]
+struct SessionStartResponse {
+    session_id: String,
+    #[serde(default)]
+    infos: Option<String>,
+    expires_at: u64,
+}
+
+/// Réponse de l'endpoint /file/url (CMAF).
+#[derive(Debug, Deserialize)]
+pub struct CmafFileUrlResponse {
+    /// Modèle d'URL avec le placeholder `$SEGMENT$`.
+    #[serde(default)]
+    pub url_template: Option<String>,
+    /// Clé de contenu enveloppée, format `"qbz-1.wrapped_b64url.iv_b64url"`.
+    #[serde(default)]
+    pub key: Option<String>,
+    /// Nombre de segments audio (hors segment init).
+    pub n_segments: u8,
+    #[serde(default)]
+    pub format_id: Option<u32>,
+    #[serde(default)]
+    pub mime_type: Option<String>,
+    #[serde(default)]
+    pub sampling_rate: Option<u32>,
+    /// Profondeur de bits (champ v1 de l'API).
+    #[serde(default)]
+    pub bits_depth: Option<u32>,
+    /// Profondeur de bits (champ v2 de l'API).
+    #[serde(default)]
+    pub bit_depth: Option<u32>,
+}
+
+impl CmafFileUrlResponse {
+    /// Retourne la profondeur de bits en préférant `bits_depth` puis `bit_depth`.
+    pub fn resolved_bit_depth(&self) -> Option<u32> {
+        self.bits_depth.or(self.bit_depth)
+    }
+}
+
+const BASE_URL: &str = "https://www.qobuz.com/api.json/0.2";
+
+fn current_timestamp() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
+/// Signe une requête /session/start.
+fn sign_session_start(timestamp: u64) -> String {
+    let mut args = std::collections::BTreeMap::new();
+    args.insert("profile", "qbz-1".to_string());
+    compute_request_sig("sessionstart", &args, &timestamp.to_string(), CMAF_SEED)
+}
+
+/// Signe une requête /file/url.
+fn sign_file_url(track_id: &str, format_id: u32, timestamp: u64) -> String {
+    let mut args = std::collections::BTreeMap::new();
+    args.insert("format_id", format_id.to_string());
+    args.insert("intent", "stream".to_string());
+    args.insert("track_id", track_id.to_string());
+    compute_request_sig("fileurl", &args, &timestamp.to_string(), CMAF_SEED)
+}
+
+/// Gestionnaire de session CMAF avec renouvellement automatique.
+///
+/// Utilise le pattern double-checked lock : fast path sous read guard,
+/// slow path sous write guard exclusif pour éviter les renouvellements
+/// concurrents qui produiraient des `infos` incohérents avec les `key`
+/// retournées par `/file/url`.
+pub struct CmafSessionManager {
+    session: RwLock<Option<CmafSession>>,
+}
+
+impl CmafSessionManager {
+    pub fn new() -> Self {
+        Self { session: RwLock::new(None) }
+    }
+
+    /// Retourne `(session_id, infos)` d'une session valide, en en démarrant
+    /// une nouvelle si la session courante est absente ou expire dans < 60s.
+    pub async fn ensure_session(
+        &self,
+        http: &reqwest::Client,
+        app_id: &str,
+        auth_token: &str,
+    ) -> Result<(String, String)> {
+        let now = current_timestamp();
+
+        // Fast path : session existante avec > 60s restants.
+        {
+            let guard = self.session.read().await;
+            if let Some(ref cs) = *guard {
+                if cs.expires_at > now + 60 {
+                    return Ok((cs.session_id.clone(), cs.infos.clone()));
+                }
+            }
+        }
+
+        // Slow path : prend le verrou d'écriture et vérifie à nouveau.
+        let mut guard = self.session.write().await;
+        if let Some(ref cs) = *guard {
+            if cs.expires_at > now + 60 {
+                return Ok((cs.session_id.clone(), cs.infos.clone()));
+            }
+        }
+
+        info!("[CMAF] Démarrage d'une nouvelle session");
+        let timestamp = current_timestamp();
+        let sig = sign_session_start(timestamp);
+
+        let url = format!("{}/session/start", BASE_URL);
+        let response = http
+            .post(&url)
+            .header("X-App-Id", app_id)
+            .header("X-User-Auth-Token", auth_token)
+            .form(&[
+                ("profile", "qbz-1"),
+                ("request_ts", &timestamp.to_string()),
+                ("request_sig", &sig),
+            ])
+            .send()
+            .await
+            .map_err(QobuzError::Http)?;
+
+        let status = response.status();
+        if !status.is_success() {
+            let body = response.text().await.unwrap_or_default();
+            return Err(QobuzError::ApiError {
+                code: status.as_u16(),
+                message: format!("session/start échoué: {}", body),
+            });
+        }
+
+        let resp: SessionStartResponse = response.json().await.map_err(|e| {
+            QobuzError::Other(format!("parse session/start: {}", e))
+        })?;
+
+        let infos = resp.infos.unwrap_or_default();
+        info!(
+            "[CMAF] Session démarrée: id={}..., expires_at={}",
+            &resp.session_id[..resp.session_id.len().min(8)],
+            resp.expires_at,
+        );
+
+        let session_id = resp.session_id.clone();
+        let infos_clone = infos.clone();
+
+        *guard = Some(CmafSession {
+            session_id: resp.session_id,
+            infos,
+            expires_at: resp.expires_at,
+        });
+
+        Ok((session_id, infos_clone))
+    }
+
+    /// Invalide la session courante (utile en cas d'erreur de déchiffrement).
+    pub async fn invalidate(&self) {
+        *self.session.write().await = None;
+    }
+}
+
+/// Récupère l'URL de fichier CMAF pour un track.
+///
+/// Inclut le retry sur les erreurs transitoires (5xx, 429, erreurs réseau).
+/// Un 404 retourne immédiatement une erreur `NotFound`.
+pub async fn get_file_url(
+    http: &reqwest::Client,
+    app_id: &str,
+    auth_token: &str,
+    session_id: &str,
+    track_id: &str,
+    format_id: u32,
+) -> Result<CmafFileUrlResponse> {
+    use crate::retry::{classify_reqwest, classify_status, retry_transient, DEFAULT_MAX_ATTEMPTS};
+
+    let url = format!("{}/file/url", BASE_URL);
+
+    let result = retry_transient(
+        DEFAULT_MAX_ATTEMPTS,
+        "CMAF file/url",
+        |e: &QobuzError| matches!(e, QobuzError::RateLimitExceeded | QobuzError::ApiError { code: 500..=599, .. }),
+        |_attempt| {
+            let url = url.clone();
+            async move {
+                let timestamp = current_timestamp();
+                let sig = sign_file_url(track_id, format_id, timestamp);
+
+                let response = http
+                    .get(&url)
+                    .header("X-App-Id", app_id)
+                    .header("X-User-Auth-Token", auth_token)
+                    .header("X-Session-Id", session_id)
+                    .query(&[
+                        ("track_id", track_id),
+                        ("format_id", &format_id.to_string()),
+                        ("intent", "stream"),
+                        ("request_ts", &timestamp.to_string()),
+                        ("request_sig", &sig),
+                    ])
+                    .send()
+                    .await
+                    .map_err(QobuzError::Http)?;
+
+                let status = response.status();
+                tracing::info!("[CMAF] file/url track_id={} format_id={} status={}", track_id, format_id, status);
+
+                if !status.is_success() {
+                    let code = status.as_u16();
+                    return Err(match code {
+                        404 => QobuzError::NotFound(format!("track {} non disponible", track_id)),
+                        429 => QobuzError::RateLimitExceeded,
+                        _ => QobuzError::ApiError {
+                            code,
+                            message: format!("file/url status {}", code),
+                        },
+                    });
+                }
+
+                let file_url: CmafFileUrlResponse = response.json().await.map_err(|e| {
+                    QobuzError::Other(format!("parse file/url: {}", e))
+                })?;
+
+                tracing::info!(
+                    "[CMAF] file/url: n_segments={}, mime={:?}, sampling_rate={:?}",
+                    file_url.n_segments,
+                    file_url.mime_type,
+                    file_url.sampling_rate,
+                );
+
+                Ok(file_url)
+            }
+        },
+    )
+    .await?;
+
+    Ok(result)
+}