global: snapshot

crates/brk_server/src/api/addresses/mod.rs

@@ -91,8 +91,8 @@ impl AddressRoutes for ApiRouter<AppState> {
                 Path(path): Path<AddressParam>,
                 State(state): State<AppState>
             | {
-                // Mempool txs for an address - use MaxAge since it's volatile
-                state.cached_json(&headers, CacheStrategy::MaxAge(5), move |q| q.address_mempool_txids(path.address)).await
+                let hash = state.sync(|q| q.address_mempool_hash(&path.address));
+                state.cached_json(&headers, CacheStrategy::MempoolHash(hash), move |q| q.address_mempool_txids(path.address)).await
             }, |op| op
                 .id("get_address_mempool_txs")
                 .addresses_tag()

crates/brk_server/src/api/mempool/mod.rs

@@ -1,8 +1,8 @@
 use aide::axum::{ApiRouter, routing::get_with};
 use axum::{extract::State, http::HeaderMap, response::Redirect, routing::get};
-use brk_types::{MempoolBlock, MempoolInfo, RecommendedFees, Txid};
+use brk_types::{Dollars, MempoolBlock, MempoolInfo, RecommendedFees, Txid};
 
-use crate::{CacheStrategy, extended::TransformResponseExtended};
+use crate::extended::TransformResponseExtended;
 
 use super::AppState;
 
@@ -18,7 +18,7 @@ impl MempoolRoutes for ApiRouter<AppState> {
                 "/api/mempool/info",
                 get_with(
                     async |headers: HeaderMap, State(state): State<AppState>| {
-                        state.cached_json(&headers, CacheStrategy::MaxAge(5), |q| q.mempool_info()).await
+                        state.cached_json(&headers, state.mempool_cache(), |q| q.mempool_info()).await
                     },
                     |op| {
                         op.id("get_mempool")
@@ -34,7 +34,7 @@ impl MempoolRoutes for ApiRouter<AppState> {
                 "/api/mempool/txids",
                 get_with(
                     async |headers: HeaderMap, State(state): State<AppState>| {
-                        state.cached_json(&headers, CacheStrategy::MaxAge(5), |q| q.mempool_txids()).await
+                        state.cached_json(&headers, state.mempool_cache(), |q| q.mempool_txids()).await
                     },
                     |op| {
                         op.id("get_mempool_txids")
@@ -50,7 +50,7 @@ impl MempoolRoutes for ApiRouter<AppState> {
                 "/api/v1/fees/recommended",
                 get_with(
                     async |headers: HeaderMap, State(state): State<AppState>| {
-                        state.cached_json(&headers, CacheStrategy::MaxAge(3), |q| q.recommended_fees()).await
+                        state.cached_json(&headers, state.mempool_cache(), |q| q.recommended_fees()).await
                     },
                     |op| {
                         op.id("get_recommended_fees")
@@ -67,7 +67,7 @@ impl MempoolRoutes for ApiRouter<AppState> {
                 get_with(
                     async |headers: HeaderMap, State(state): State<AppState>| {
                         state
-                            .cached_json(&headers, CacheStrategy::MaxAge(5), |q| q.live_price())
+                            .cached_json(&headers, state.mempool_cache(), |q| q.live_price())
                             .await
                     },
                     |op| {
@@ -75,11 +75,11 @@ impl MempoolRoutes for ApiRouter<AppState> {
                             .mempool_tag()
                             .summary("Live BTC/USD price")
                             .description(
-                                "Returns the current BTC/USD price in cents, derived from \
+                                "Returns the current BTC/USD price in dollars, derived from \
                                 on-chain round-dollar output patterns in the last 12 blocks \
                                 plus mempool.",
                             )
-                            .ok_response::<u64>()
+                            .ok_response::<Dollars>()
                             .server_error()
                     },
                 ),
@@ -88,7 +88,7 @@ impl MempoolRoutes for ApiRouter<AppState> {
                 "/api/v1/fees/mempool-blocks",
                 get_with(
                     async |headers: HeaderMap, State(state): State<AppState>| {
-                        state.cached_json(&headers, CacheStrategy::MaxAge(5), |q| q.mempool_blocks()).await
+                        state.cached_json(&headers, state.mempool_cache(), |q| q.mempool_blocks()).await
                     },
                     |op| {
                         op.id("get_mempool_blocks")

crates/brk_server/src/cache.rs

@@ -12,9 +12,9 @@ pub enum CacheStrategy {
     /// Etag = VERSION only, Cache-Control: must-revalidate
     Static,
 
-    /// Volatile data (mempool) - no etag, just max-age
-    /// Cache-Control: max-age={seconds}
-    MaxAge(u64),
+    /// Mempool data - etag from next projected block hash + short max-age
+    /// Etag = VERSION-m{hash:x}, Cache-Control: max-age=1, must-revalidate
+    MempoolHash(u64),
 }
 
 /// Resolved cache parameters
@@ -50,9 +50,9 @@ impl CacheParams {
                 etag: Some(VERSION.to_string()),
                 cache_control: "public, max-age=1, must-revalidate".into(),
             },
-            MaxAge(secs) => Self {
-                etag: None,
-                cache_control: format!("public, max-age={secs}"),
+            MempoolHash(hash) => Self {
+                etag: Some(format!("{VERSION}-m{hash:x}")),
+                cache_control: "public, max-age=1, must-revalidate".into(),
             },
         }
     }

crates/brk_server/src/state.rs

@@ -30,6 +30,11 @@ pub struct AppState {
 }
 
 impl AppState {
+    pub fn mempool_cache(&self) -> CacheStrategy {
+        let hash = self.sync(|q| q.mempool().map(|m| m.next_block_hash()).unwrap_or(0));
+        CacheStrategy::MempoolHash(hash)
+    }
+
     /// JSON response with caching
     pub async fn cached_json<T, F>(
         &self,