1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
package main
import (
"errors"
"io/ioutil"
"strings"
"sync"
"time"
)
const cacheDuration = 1 * time.Minute
// Holds the cached responses
type page struct {
raw []byte
expires time.Time
}
// Wraps the page cache map with a rwlock
type cacheWrapper struct {
sync.RWMutex
pages map[string]*page
}
// The actual page/response cache
var cache = &cacheWrapper{
pages: make(map[string]*page),
}
// Checks if a page exists in the cache already.
// If it doesn't, creates an empty entry.
func (cache *cacheWrapper) checkedInit(path string) {
cache.Lock()
defer cache.Unlock()
if cache.pages[path] == nil {
cache.pages[path] = &page{
raw: []byte{},
expires: time.Time{},
}
}
}
// Adds a given page to the cache with path as the key
func (cache *cacheWrapper) insert(path string, raw []byte) {
cache.Lock()
defer cache.Unlock()
cache.pages[path] = &page{
raw: raw,
expires: time.Now().Add(cacheDuration),
}
}
// Returns true if the cached page is good.
// False if it's stale.
func (cache *cacheWrapper) isFresh(path string) bool {
cache.RLock()
defer cache.RUnlock()
return time.Now().Before(cache.pages[path].expires)
}
// Wraps the two cache-checking functions.
// One for /, the other for various requests.
func (cache *cacheWrapper) bap(requestPath string) error {
cache.checkedInit(requestPath)
if cache.isFresh(requestPath) {
return nil
}
var format, query string
if requestPath != "/" {
split := strings.Split(requestPath[1:], "/")
format = split[0]
query = split[1]
}
var bytes []byte
var err error
switch query {
case "osversion":
bytes, err = osVersionQuery(format)
case "uptime":
bytes, err = uptimeQuery(format)
case "usercount":
bytes, err = userCountQuery(format)
case "users":
bytes, err = usersQuery(format)
case "pkgs":
bytes, err = pkgsQuery(format)
default:
if requestPath == "/" {
bytes, err = ioutil.ReadFile("web/index.txt")
} else {
err = errors.New("Invalid Query Type")
}
}
if err != nil {
return err
}
cache.insert(requestPath, bytes)
return nil
}
// yoinks the raw data and expiry time to send to the requester
func (cache *cacheWrapper) yoink(path string) ([]byte, string) {
cache.RLock()
defer cache.RUnlock()
return cache.pages[path].raw, cache.pages[path].expires.Format(time.RFC1123)
}
|