1 635ade7f 2024-04-10 o package lemmy
 2 635ade7f 2024-04-10 o 
 3 635ade7f 2024-04-10 o import (
 4 635ade7f 2024-04-10 o 	"fmt"
 5 635ade7f 2024-04-10 o 	"net/http"
 6 635ade7f 2024-04-10 o 	"strconv"
 7 635ade7f 2024-04-10 o 	"strings"
 8 635ade7f 2024-04-10 o 	"sync"
 9 635ade7f 2024-04-10 o 	"time"
10 635ade7f 2024-04-10 o )
11 635ade7f 2024-04-10 o 
12 635ade7f 2024-04-10 o type cache struct {
13 635ade7f 2024-04-10 o 	post      map[int]entry
14 635ade7f 2024-04-10 o 	community map[string]entry
15 635ade7f 2024-04-10 o 	mu        *sync.Mutex
16 635ade7f 2024-04-10 o }
17 635ade7f 2024-04-10 o 
18 635ade7f 2024-04-10 o type entry struct {
19 635ade7f 2024-04-10 o 	post      Post
20 635ade7f 2024-04-10 o 	community Community
21 635ade7f 2024-04-10 o 	expiry    time.Time
22 635ade7f 2024-04-10 o }
23 635ade7f 2024-04-10 o 
24 635ade7f 2024-04-10 o func (c *cache) store(p Post, com Community, dur time.Duration) {
25 635ade7f 2024-04-10 o 	c.mu.Lock()
26 635ade7f 2024-04-10 o 	defer c.mu.Unlock()
27 635ade7f 2024-04-10 o 	t := time.Now().Add(dur)
28 635ade7f 2024-04-10 o 	entry := entry{expiry: t}
29 635ade7f 2024-04-10 o 	if p.Name() != "" {
30 635ade7f 2024-04-10 o 		entry.post = p
31 635ade7f 2024-04-10 o 		c.post[p.ID] = entry
32 635ade7f 2024-04-10 o 	}
33 635ade7f 2024-04-10 o 	if com.Name() != "" {
34 635ade7f 2024-04-10 o 		entry.community = com
35 635ade7f 2024-04-10 o 		c.community[com.Name()] = entry
36 635ade7f 2024-04-10 o 	}
37 635ade7f 2024-04-10 o }
38 635ade7f 2024-04-10 o 
39 635ade7f 2024-04-10 o func (c *cache) delete(p Post, com Community) {
40 635ade7f 2024-04-10 o 	c.mu.Lock()
41 635ade7f 2024-04-10 o 	defer c.mu.Unlock()
42 635ade7f 2024-04-10 o 	delete(c.post, p.ID)
43 635ade7f 2024-04-10 o 	delete(c.community, com.Name())
44 635ade7f 2024-04-10 o }
45 635ade7f 2024-04-10 o 
46 635ade7f 2024-04-10 o // max-age=50
47 635ade7f 2024-04-10 o func parseMaxAge(s string) (time.Duration, error) {
48 635ade7f 2024-04-10 o 	var want string
49 635ade7f 2024-04-10 o 	elems := strings.Split(s, ",")
50 635ade7f 2024-04-10 o 	for i := range elems {
51 635ade7f 2024-04-10 o 		elems[i] = strings.TrimSpace(elems[i])
52 635ade7f 2024-04-10 o 		if strings.HasPrefix(elems[i], "max-age") {
53 635ade7f 2024-04-10 o 			want = elems[i]
54 635ade7f 2024-04-10 o 		}
55 635ade7f 2024-04-10 o 	}
56 635ade7f 2024-04-10 o 	_, num, found := strings.Cut(want, "=")
57 635ade7f 2024-04-10 o 	if !found {
58 635ade7f 2024-04-10 o 		return 0, fmt.Errorf("missing = separator")
59 635ade7f 2024-04-10 o 	}
60 635ade7f 2024-04-10 o 	n, err := strconv.Atoi(num)
61 635ade7f 2024-04-10 o 	if err != nil {
62 635ade7f 2024-04-10 o 		return 0, fmt.Errorf("parse seconds: %w", err)
63 635ade7f 2024-04-10 o 	}
64 635ade7f 2024-04-10 o 	return time.Duration(n) * time.Second, nil
65 635ade7f 2024-04-10 o }
66 635ade7f 2024-04-10 o 
67 635ade7f 2024-04-10 o // Cache-Control: public, max-age=50
68 635ade7f 2024-04-10 o func extractMaxAge(header http.Header) string {
69 635ade7f 2024-04-10 o 	cc := header.Get("Cache-Control")
70 635ade7f 2024-04-10 o 	if !strings.Contains(cc, "max-age=") {
71 635ade7f 2024-04-10 o 		return ""
72 635ade7f 2024-04-10 o 	}
73 635ade7f 2024-04-10 o 	return cc
74 635ade7f 2024-04-10 o }