refactor: simplify architecture with focused modules and test harness

src/config.rs

@@ -39,17 +39,15 @@ use tokio::sync::Semaphore;
 use tracing::debug;
 use zeroize::Zeroizing;
 
-use crate::crypto::nip59::DEFAULT_MAX_TOKENS_PER_EVENT;
-use crate::error::Result;
-use crate::nostr::events::{
-    DEFAULT_DEDUP_RETENTION_SECS, DEFAULT_MAX_NOTIFICATION_AGE_SECS,
+use crate::defaults::{
+    DEFAULT_DEDUP_RETENTION_SECS, DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_HOUR,
+    DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_MINUTE, DEFAULT_MAX_CONCURRENT_EVENT_PROCESSING,
+    DEFAULT_MAX_DEDUP_CACHE_SIZE, DEFAULT_MAX_NOTIFICATION_AGE_SECS,
     DEFAULT_MAX_NOTIFICATION_FUTURE_SKEW_SECS,
+    DEFAULT_MAX_SIZE as DEFAULT_MAX_RATE_LIMIT_CACHE_SIZE, DEFAULT_MAX_TOKENS_PER_EVENT,
+    DEFAULT_RATE_LIMIT_PER_HOUR, DEFAULT_RATE_LIMIT_PER_MINUTE,
 };
-use crate::rate_limiter::{
-    DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_HOUR, DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_MINUTE,
-    DEFAULT_MAX_SIZE as DEFAULT_MAX_RATE_LIMIT_CACHE_SIZE, DEFAULT_RATE_LIMIT_PER_HOUR,
-    DEFAULT_RATE_LIMIT_PER_MINUTE,
-};
+use crate::error::Result;
 
 /// Root configuration structure.
 #[derive(Debug, Clone, Deserialize)]
@@ -79,18 +77,9 @@ pub struct AppConfig {
     pub glitchtip: GlitchtipConfig,
 }
 
-/// Default maximum size for the deduplication cache.
-const DEFAULT_MAX_DEDUP_CACHE_SIZE: usize = 100_000;
 const DEFAULT_HEALTH_BIND_ADDRESS: &str = "127.0.0.1:8080";
 const ENV_PREFIX: &str = "TRANSPONDER_";
 
-/// Default maximum number of events processed concurrently.
-///
-/// Caps the total in-flight gift-wrap unwrap (ECDH) work so a flood cannot
-/// spawn unbounded crypto tasks, while still draining the relay broadcast
-/// channel quickly enough to avoid `Lagged` overflow.
-const DEFAULT_MAX_CONCURRENT_EVENT_PROCESSING: usize = 64;
-
 fn default_max_dedup_cache_size() -> usize {
     DEFAULT_MAX_DEDUP_CACHE_SIZE
 }

src/crypto/nip59.rs

@@ -16,8 +16,7 @@ const TAG_ENCODING: &str = "encoding";
 const VERSION_MIP05_V1: &str = "mip05-v1";
 const ENCODING_BASE64: &str = "base64";
 
-/// Default maximum number of encrypted tokens accepted in one notification event.
-pub const DEFAULT_MAX_TOKENS_PER_EVENT: usize = 100;
+pub use crate::defaults::DEFAULT_MAX_TOKENS_PER_EVENT;
 
 /// Maximum number of characters of attacker-controlled tag content included in
 /// error messages.

src/defaults.rs

@@ -0,0 +1,60 @@
+//! Centralized default values for configuration and runtime components.
+//!
+//! Single source of truth for serde defaults in [`crate::config`] and for
+//! runtime components that share the same tuning knobs.
+
+use nostr_sdk::prelude::nip59;
+
+/// Maximum NIP-59 timestamp randomization window for gift wraps (seconds).
+pub const NIP59_TIMESTAMP_TWEAK_WINDOW_SECS: u64 = nip59::RANGE_RANDOM_TIMESTAMP_TWEAK.end;
+
+// === Rate limiting ===
+
+/// Default maximum cache size (100,000 entries).
+pub const DEFAULT_MAX_SIZE: usize = 100_000;
+
+/// Default rate limit per minute (240 = 4 per second).
+pub const DEFAULT_RATE_LIMIT_PER_MINUTE: u32 = 240;
+
+/// Default rate limit per hour.
+pub const DEFAULT_RATE_LIMIT_PER_HOUR: u32 = 5000;
+
+/// Default global pre-unwrap admission limit per minute.
+pub const DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_MINUTE: u32 = 600;
+
+/// Default global pre-unwrap admission limit per hour.
+pub const DEFAULT_GLOBAL_UNWRAP_LIMIT_PER_HOUR: u32 = 30_000;
+
+// === Event processing / replay protection ===
+
+/// Default maximum size for the volatile deduplication cache.
+pub const DEFAULT_MAX_DEDUP_CACHE_SIZE: usize = 100_000;
+
+/// Default maximum age for the unwrapped kind:446 notification request rumor.
+pub const DEFAULT_MAX_NOTIFICATION_AGE_SECS: u64 = 3_600;
+
+/// Default tolerated clock skew for future-dated notification rumors.
+pub const DEFAULT_MAX_NOTIFICATION_FUTURE_SKEW_SECS: u64 = 300;
+
+/// Default duration to keep processed gift-wrap event IDs in replay state.
+pub const DEFAULT_DEDUP_RETENTION_SECS: u64 =
+    NIP59_TIMESTAMP_TWEAK_WINDOW_SECS + DEFAULT_MAX_NOTIFICATION_FUTURE_SKEW_SECS;
+
+/// Default maximum number of encrypted tokens accepted in one notification event.
+pub const DEFAULT_MAX_TOKENS_PER_EVENT: usize = 100;
+
+/// Default maximum number of events processed concurrently.
+pub const DEFAULT_MAX_CONCURRENT_EVENT_PROCESSING: usize = 64;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn dedup_retention_matches_nip59_window_plus_skew() {
+        assert_eq!(
+            DEFAULT_DEDUP_RETENTION_SECS,
+            NIP59_TIMESTAMP_TWEAK_WINDOW_SECS + DEFAULT_MAX_NOTIFICATION_FUTURE_SKEW_SECS
+        );
+    }
+}

src/lib.rs

@@ -0,0 +1,27 @@
+//! Transponder - MIP-05 Push Notification Server
+//!
+//! A privacy-preserving push notification server implementing the Marmot MIP-05
+//! specification.
+
+pub mod app;
+pub mod config;
+pub mod crypto;
+pub mod defaults;
+pub mod error;
+pub mod metrics;
+pub mod nostr;
+pub mod push;
+pub mod rate_limiter;
+pub mod redaction;
+pub mod server;
+pub mod shutdown;
+pub mod telemetry;
+
+#[cfg(test)]
+pub(crate) mod test_metrics;
+#[cfg(test)]
+pub(crate) mod test_support;
+#[cfg(test)]
+pub(crate) mod test_vectors;
+
+pub use app::run;