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.
23#[derive(Debug)]
24pub struct DateService {
25    current: Arc<ArcSwap<Bytes>>,
26    handle: tokio::task::JoinHandle<()>,
27}
28
29static DATE_SERVICE: Lazy<DateService> = Lazy::new(|| DateService::new_with_update_interval(Duration::from_millis(800)));
30
31impl DateService {
32    /// Returns a reference to the global singleton instance of `DateService`.
33    ///
34    /// This method provides access to a shared `DateService` instance that can be used
35    /// across the application to efficiently handle HTTP date headers.
36    ///
37    /// # Returns
38    /// A static reference to the global `DateService` instance.
39    pub fn get_global_instance() -> &'static DateService {
40        &DATE_SERVICE
41    }
42
43    /// Creates a new `DateService` instance.
44    ///
45    /// This method initializes the service with the current system time and starts
46    /// a background task that updates the date string every 700ms.
47    ///
48    /// # Returns
49    /// Returns a new `DateService` instance with the background update task running.
50    fn new_with_update_interval(update_interval: Duration) -> Self {
51        let mut buf = faf_http_date::get_date_buff_no_key();
52        faf_http_date::get_date_no_key(&mut buf);
53        let bytes = Bytes::from_owner(buf);
54
55        let current = Arc::new(ArcSwap::from_pointee(bytes));
56        let current_arc = Arc::clone(&current);
57
58        let handle = tokio::spawn(async move {
59            loop {
60                tokio::time::sleep(update_interval).await;
61                let mut buf = faf_http_date::get_date_buff_no_key();
62                faf_http_date::get_date_no_key(&mut buf);
63                let bytes = Bytes::from_owner(buf);
64                current_arc.store(Arc::new(bytes));
65            }
66        });
67
68        DateService { current, handle }
69    }
70
71    /// Provides access to the current HTTP date string through a callback function.
72    ///
73    /// This method allows safe access to the current date string without exposing
74    /// the internal synchronization mechanisms.
75    pub(crate) fn with_http_date<F>(&self, mut f: F)
76    where
77        F: FnMut(HeaderValue),
78    {
79        let date = self.current.load().as_ref().clone();
80        // SAFE: date is created by faf_http_date, it's valid
81        let header_value = unsafe { HeaderValue::from_maybe_shared_unchecked(date) };
82        f(header_value)
83    }
84}
85
86/// Implements the `Drop` trait to ensure the background task is properly cleaned up
87/// when the `DateService` is dropped.
88impl Drop for DateService {
89    fn drop(&mut self) {
90        self.handle.abort();
91    }
92}
micro_web/date/mod.rs

micro_web/date/
mod.rs
