1 1081cf75 2024-11-04 o package lemmy
 2 1081cf75 2024-11-04 o 
 3 1081cf75 2024-11-04 o import (
 4 1081cf75 2024-11-04 o 	"fmt"
 5 1081cf75 2024-11-04 o 	"net/http"
 6 1081cf75 2024-11-04 o 	"strconv"
 7 1081cf75 2024-11-04 o 	"strings"
 8 1081cf75 2024-11-04 o 	"sync"
 9 1081cf75 2024-11-04 o 	"time"
10 1081cf75 2024-11-04 o )
11 1081cf75 2024-11-04 o 
12 1081cf75 2024-11-04 o type cache struct {
13 1081cf75 2024-11-04 o 	post      map[int]entry
14 1081cf75 2024-11-04 o 	community map[string]entry
15 1081cf75 2024-11-04 o 	mu        *sync.Mutex
16 1081cf75 2024-11-04 o }
17 1081cf75 2024-11-04 o 
18 1081cf75 2024-11-04 o type entry struct {
19 1081cf75 2024-11-04 o 	post      Post
20 1081cf75 2024-11-04 o 	community Community
21 1081cf75 2024-11-04 o 	expiry    time.Time
22 1081cf75 2024-11-04 o }
23 1081cf75 2024-11-04 o 
24 1081cf75 2024-11-04 o func (c *cache) store(p Post, com Community, dur time.Duration) {
25 1081cf75 2024-11-04 o 	c.mu.Lock()
26 1081cf75 2024-11-04 o 	defer c.mu.Unlock()
27 1081cf75 2024-11-04 o 	t := time.Now().Add(dur)
28 1081cf75 2024-11-04 o 	entry := entry{expiry: t}
29 1081cf75 2024-11-04 o 	if p.Name() != "" {
30 1081cf75 2024-11-04 o 		entry.post = p
31 1081cf75 2024-11-04 o 		c.post[p.ID] = entry
32 1081cf75 2024-11-04 o 	}
33 1081cf75 2024-11-04 o 	if com.Name() != "" {
34 1081cf75 2024-11-04 o 		entry.community = com
35 1081cf75 2024-11-04 o 		c.community[com.Name()] = entry
36 1081cf75 2024-11-04 o 	}
37 1081cf75 2024-11-04 o }
38 1081cf75 2024-11-04 o 
39 1081cf75 2024-11-04 o func (c *cache) delete(p Post, com Community) {
40 1081cf75 2024-11-04 o 	c.mu.Lock()
41 1081cf75 2024-11-04 o 	defer c.mu.Unlock()
42 1081cf75 2024-11-04 o 	delete(c.post, p.ID)
43 1081cf75 2024-11-04 o 	delete(c.community, com.Name())
44 1081cf75 2024-11-04 o }
45 1081cf75 2024-11-04 o 
46 1081cf75 2024-11-04 o // max-age=50
47 1081cf75 2024-11-04 o func parseMaxAge(s string) (time.Duration, error) {
48 1081cf75 2024-11-04 o 	var want string
49 1081cf75 2024-11-04 o 	elems := strings.Split(s, ",")
50 1081cf75 2024-11-04 o 	for i := range elems {
51 1081cf75 2024-11-04 o 		elems[i] = strings.TrimSpace(elems[i])
52 1081cf75 2024-11-04 o 		if strings.HasPrefix(elems[i], "max-age") {
53 1081cf75 2024-11-04 o 			want = elems[i]
54 1081cf75 2024-11-04 o 		}
55 1081cf75 2024-11-04 o 	}
56 1081cf75 2024-11-04 o 	_, num, found := strings.Cut(want, "=")
57 1081cf75 2024-11-04 o 	if !found {
58 1081cf75 2024-11-04 o 		return 0, fmt.Errorf("missing = separator")
59 1081cf75 2024-11-04 o 	}
60 1081cf75 2024-11-04 o 	n, err := strconv.Atoi(num)
61 1081cf75 2024-11-04 o 	if err != nil {
62 1081cf75 2024-11-04 o 		return 0, fmt.Errorf("parse seconds: %w", err)
63 1081cf75 2024-11-04 o 	}
64 1081cf75 2024-11-04 o 	return time.Duration(n) * time.Second, nil
65 1081cf75 2024-11-04 o }
66 1081cf75 2024-11-04 o 
67 1081cf75 2024-11-04 o // Cache-Control: public, max-age=50
68 1081cf75 2024-11-04 o func extractMaxAge(header http.Header) string {
69 1081cf75 2024-11-04 o 	cc := header.Get("Cache-Control")
70 1081cf75 2024-11-04 o 	if !strings.Contains(cc, "max-age=") {
71 1081cf75 2024-11-04 o 		return ""
72 1081cf75 2024-11-04 o 	}
73 1081cf75 2024-11-04 o 	return cc
74 1081cf75 2024-11-04 o }