lib

commit 5f136f7a29d00ab53676d7f3cd7b9f144a97326d
parent ea16d393a4fbeca4c1b1cedcebe991e1e50244ec
Author: triesap <tyson@radroots.org>
Date:   Mon, 25 May 2026 04:53:27 +0000

local_events: add relay set fingerprint

Diffstat:
M
crates/local_events/src/lib.rs
 | 
2
++
A
crates/local_events/src/relay_set.rs
 | 
49
+++++++++++++++++++++++++++++++++++++++++++++++++
A
crates/local_events/tests/relay_set.rs
 | 
36
++++++++++++++++++++++++++++++++++++

3 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/crates/local_events/src/lib.rs b/crates/local_events/src/lib.rs
@@ -4,6 +4,7 @@ mod error;
 mod migrations;
 mod models;
 mod order_work;
+mod relay_set;
 mod store;
 
 pub use error::LocalEventsError;
@@ -21,4 +22,5 @@ pub use order_work::{
     validate_supported_buyer_order_request_local_work_payload,
     validate_unsupported_buyer_order_request_local_work_payload,
 };
+pub use relay_set::{CANONICAL_RELAY_SET_FINGERPRINT_VERSION, canonical_relay_set_fingerprint};
 pub use store::LocalEventsStore;
diff --git a/crates/local_events/src/relay_set.rs b/crates/local_events/src/relay_set.rs
@@ -0,0 +1,49 @@
+#![forbid(unsafe_code)]
+
+use std::collections::BTreeSet;
+
+const FNV_1A_64_OFFSET_BASIS: u64 = 0xcbf29ce484222325;
+const FNV_1A_64_PRIME: u64 = 0x100000001b3;
+
+pub const CANONICAL_RELAY_SET_FINGERPRINT_VERSION: &str = "radroots-local-events-relay-set-v1";
+
+/// Returns the canonical shared local-event relay-set fingerprint.
+///
+/// Relay URLs are trimmed, blank entries are discarded, duplicates are removed,
+/// and the remaining set is sorted before hashing.
+pub fn canonical_relay_set_fingerprint<I, S>(relay_urls: I) -> Option<String>
+where
+    I: IntoIterator<Item = S>,
+    S: AsRef<str>,
+{
+    let relays = relay_urls
+        .into_iter()
+        .filter_map(|relay_url| {
+            let relay_url = relay_url.as_ref().trim();
+            (!relay_url.is_empty()).then(|| relay_url.to_owned())
+        })
+        .collect::<BTreeSet<_>>();
+
+    if relays.is_empty() {
+        return None;
+    }
+
+    let mut hash = FNV_1A_64_OFFSET_BASIS;
+    for relay in relays {
+        update_hash(&mut hash, relay.len().to_string().as_bytes());
+        update_hash(&mut hash, &[0]);
+        update_hash(&mut hash, relay.as_bytes());
+        update_hash(&mut hash, &[0]);
+    }
+
+    Some(format!(
+        "{CANONICAL_RELAY_SET_FINGERPRINT_VERSION}:{hash:016x}"
+    ))
+}
+
+fn update_hash(hash: &mut u64, bytes: &[u8]) {
+    for byte in bytes {
+        *hash ^= u64::from(*byte);
+        *hash = hash.wrapping_mul(FNV_1A_64_PRIME);
+    }
+}
diff --git a/crates/local_events/tests/relay_set.rs b/crates/local_events/tests/relay_set.rs
@@ -0,0 +1,36 @@
+use radroots_local_events::{
+    CANONICAL_RELAY_SET_FINGERPRINT_VERSION, canonical_relay_set_fingerprint,
+};
+
+#[test]
+fn relay_set_fingerprint_trims_sorts_and_dedupes() {
+    let first = canonical_relay_set_fingerprint([
+        " wss://relay-b.example ",
+        "wss://relay-a.example",
+        "wss://relay-b.example",
+    ])
+    .expect("fingerprint");
+    let second =
+        canonical_relay_set_fingerprint(["wss://relay-a.example", "wss://relay-b.example"])
+            .expect("fingerprint");
+
+    assert_eq!(first, second);
+    assert!(first.starts_with(CANONICAL_RELAY_SET_FINGERPRINT_VERSION));
+}
+
+#[test]
+fn relay_set_fingerprint_rejects_empty_entries() {
+    let fingerprint = canonical_relay_set_fingerprint([" ", "", "\t"]);
+
+    assert_eq!(fingerprint, None);
+}
+
+#[test]
+fn relay_set_fingerprint_changes_when_relay_set_changes() {
+    let first = canonical_relay_set_fingerprint(["wss://relay-a.example"]).expect("fingerprint");
+    let second =
+        canonical_relay_set_fingerprint(["wss://relay-a.example", "wss://relay-b.example"])
+            .expect("fingerprint");
+
+    assert_ne!(first, second);
+}