gsm_core/
idempotency.rs

1//! Idempotency helpers for webhook/event processing.
2use std::{
3    collections::HashSet,
4    hash::{Hash, Hasher},
5    sync::{Arc, Mutex},
6    time::{Duration, Instant},
7};
8
9/// Composite idempotency key identifying an incoming message uniquely.
10///
11/// ```
12/// use gsm_core::IdKey;
13///
14/// let key = IdKey {
15///     platform: "telegram".into(),
16///     chat_id: "chat-1".into(),
17///     msg_id: "msg-1".into(),
18/// };
19/// assert_eq!(key.platform, "telegram");
20/// ```
21#[derive(Debug, Clone, PartialEq, Eq, Hash)]
22pub struct IdKey {
23    pub platform: String,
24    pub chat_id: String,
25    pub msg_id: String,
26}
27
28/// Very small in-memory seen-set with TTL. Intended for single-process demos/tests.
29#[derive(Clone)]
30pub struct SeenSet {
31    inner: Arc<Mutex<Inner>>,
32    ttl: Duration,
33}
34
35struct Inner {
36    set: HashSet<u64>,
37    times: Vec<(u64, Instant)>,
38}
39
40impl SeenSet {
41    /// Creates a new `SeenSet` that evicts entries after `ttl`.
42    ///
43    /// ```
44    /// use gsm_core::{IdKey, SeenSet};
45    /// use std::time::Duration;
46    ///
47    /// let set = SeenSet::new(Duration::from_secs(1));
48    /// let key = IdKey {
49    ///     platform: "telegram".into(),
50    ///     chat_id: "chat-1".into(),
51    ///     msg_id: "msg-1".into(),
52    /// };
53    /// assert!(!set.seen_or_insert(&key));
54    /// assert!(set.seen_or_insert(&key));
55    /// ```
56    pub fn new(ttl: Duration) -> Self {
57        Self {
58            inner: Arc::new(Mutex::new(Inner {
59                set: HashSet::new(),
60                times: Vec::new(),
61            })),
62            ttl,
63        }
64    }
65
66    fn key_hash(k: &IdKey) -> u64 {
67        let mut hasher = std::collections::hash_map::DefaultHasher::new();
68        k.hash(&mut hasher);
69        hasher.finish()
70    }
71
72    /// Returns `true` when the key has been seen recently, or stores it and returns `false`.
73    pub fn seen_or_insert(&self, key: &IdKey) -> bool {
74        let now = Instant::now();
75        let mut g = self.inner.lock().unwrap();
76        // GC old entries
77        let mut expired = Vec::new();
78        g.times.retain(|(h, t)| {
79            if now.duration_since(*t) > self.ttl {
80                expired.push(*h);
81                false
82            } else {
83                true
84            }
85        });
86        for h in expired {
87            g.set.remove(&h);
88        }
89        let h = Self::key_hash(key);
90        if g.set.contains(&h) {
91            return true;
92        }
93        g.set.insert(h);
94        g.times.push((h, now));
95        false
96    }
97}
98
99#[cfg(test)]
100mod tests {
101    use super::*;
102    use std::time::Duration;
103
104    #[test]
105    fn idempotency_basic() {
106        let s = SeenSet::new(Duration::from_millis(50));
107        let k = IdKey {
108            platform: "telegram".into(),
109            chat_id: "c1".into(),
110            msg_id: "m1".into(),
111        };
112        assert!(!s.seen_or_insert(&k));
113        assert!(s.seen_or_insert(&k));
114    }
115
116    #[test]
117    fn idempotency_entries_expire() {
118        let s = SeenSet::new(Duration::from_millis(10));
119        let k = IdKey {
120            platform: "telegram".into(),
121            chat_id: "c1".into(),
122            msg_id: "m1".into(),
123        };
124        assert!(!s.seen_or_insert(&k));
125        std::thread::sleep(Duration::from_millis(20));
126        assert!(!s.seen_or_insert(&k));
127    }
128}
gsm_core/idempotency.rs

gsm_core/
idempotency.rs
