micro_web/date/
mod.rs

1//! HTTP date header value management service.
2//!
3//! This module provides a service for efficiently managing and updating HTTP date header values
4//! in a concurrent environment. It updates the date string periodically to avoid repeated
5//! date string formatting operations in high-concurrency scenarios.
6
7use arc_swap::ArcSwap;
8use bytes::Bytes;
9use http::HeaderValue;
10use once_cell::sync::Lazy;
11use std::sync::Arc;
12use std::time::Duration;
13
14mod date_service_decorator;
15
16pub use date_service_decorator::DateServiceDecorator;
17
18/// A service that maintains and periodically updates the current HTTP date string.
19///
20/// This service runs a background task that updates the date string every 700ms,
21/// providing an efficient way to access formatted HTTP date strings without
22/// formatting them on every request.
23pub struct DateService {
24    current: Arc<ArcSwap<Bytes>>,
25    handle: tokio::task::JoinHandle<()>,
26}
27
28static DATE_SERVICE: Lazy<DateService> = Lazy::new(|| DateService::new_with_update_interval(Duration::from_millis(800)));
29
30impl DateService {
31    /// Returns a reference to the global singleton instance of `DateService`.
32    ///
33    /// This method provides access to a shared `DateService` instance that can be used
34    /// across the application to efficiently handle HTTP date headers.
35    ///
36    /// # Returns
37    /// A static reference to the global `DateService` instance.
38    pub fn get_global_instance() -> &'static DateService {
39        &DATE_SERVICE
40    }
41
42    /// Creates a new `DateService` instance.
43    ///
44    /// This method initializes the service with the current system time and starts
45    /// a background task that updates the date string every 700ms.
46    ///
47    /// # Returns
48    /// Returns a new `DateService` instance with the background update task running.
49    fn new_with_update_interval(update_interval: Duration) -> Self {
50        let mut buf = faf_http_date::get_date_buff_no_key();
51        faf_http_date::get_date_no_key(&mut buf);
52        let bytes = Bytes::from_owner(buf);
53
54        let current = Arc::new(ArcSwap::from_pointee(bytes));
55        let current_arc = Arc::clone(&current);
56
57        let handle = tokio::spawn(async move {
58            loop {
59                tokio::time::sleep(update_interval).await;
60                let mut buf = faf_http_date::get_date_buff_no_key();
61                faf_http_date::get_date_no_key(&mut buf);
62                let bytes = Bytes::from_owner(buf);
63                current_arc.store(Arc::new(bytes));
64            }
65        });
66
67        DateService { current, handle }
68    }
69
70    /// Provides access to the current HTTP date string through a callback function.
71    ///
72    /// This method allows safe access to the current date string without exposing
73    /// the internal synchronization mechanisms.
74    pub(crate) fn with_http_date<F>(&self, mut f: F)
75    where
76        F: FnMut(HeaderValue),
77    {
78        let date = self.current.load().as_ref().clone();
79        // SAFE: date is created by faf_http_date, it's valid
80        let header_value = unsafe { HeaderValue::from_maybe_shared_unchecked(date) };
81        f(header_value)
82    }
83}
84
85/// Implements the `Drop` trait to ensure the background task is properly cleaned up
86/// when the `DateService` is dropped.
87impl Drop for DateService {
88    fn drop(&mut self) {
89        self.handle.abort();
90    }
91}
micro_web/date/mod.rs

micro_web/date/
mod.rs
