This repository has been archived by the owner on May 7, 2024. It is now read-only.
-
-
Notifications
You must be signed in to change notification settings - Fork 0
/
xkcd.go
140 lines (112 loc) · 2.68 KB
/
xkcd.go
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
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
package main
import (
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"os"
"path"
"path/filepath"
"strings"
"github.com/karlseguin/typed"
)
func get(url string) ([]byte, error) {
res, err := http.DefaultClient.Get(url)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("unexpected status code: %d", res.StatusCode)
}
data, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
return data, nil
}
func getJSON(url string) (typed.Typed, error) {
data, err := get(url)
if err != nil {
return nil, err
}
m, err := typed.Json(data)
if err != nil {
return nil, err
}
return m, nil
}
func getComicMetadata(id uint) (typed.Typed, error) {
return getJSON(fmt.Sprintf("https://xkcd.com/%d/info.0.json", id))
}
func getLatestID() (uint, error) {
m, err := getJSON("https://xkcd.com/info.0.json")
if err != nil {
return 0, err
}
id, ok := m.IntIf("num")
if !ok {
return 0, errors.New("key 'num' does not exist")
}
return uint(id), nil
}
func getImage(url string) ([]byte, error) {
ext := path.Ext(url)
url = strings.TrimSuffix(url, ext)
data, err := get(url + "_2x" + ext)
if err != nil {
data, err = get(url + ext)
}
return data, err
}
// ensureComic fetches comic #id and stores it in out. Returns metadata.
func ensureComic(out string, id uint) (typed.Typed, error) {
err := os.MkdirAll(out, dirPermissions)
if err != nil {
return nil, err
}
metadata, err := getComicMetadata(id)
if err != nil {
return nil, err
}
// Some comics, such as 1608 and 1663, are composed by interactive
// games and cannot be downloaded as images, so we just ignore them.
if imgURL := metadata.StringOr("img", "https://imgs.xkcd.com/comics/"); imgURL != "https://imgs.xkcd.com/comics/" {
imgBytes, err := getImage(imgURL)
if err != nil {
return nil, err
}
imgName := path.Base(imgURL)
err = os.WriteFile(filepath.Join(out, imgName), imgBytes, filePermissions)
if err != nil {
return nil, err
}
metadata["img"] = "./" + imgName
} else {
metadata["img"] = ""
}
infoBytes, err := json.MarshalIndent(metadata, "", " ")
if err != nil {
return nil, err
}
err = os.WriteFile(filepath.Join(out, "info.json"), infoBytes, filePermissions)
if err != nil {
return nil, err
}
return metadata, nil
}
// getComic gets comic #id metadata from out, or fetches from Internet.
func getComic(out string, id uint) (typed.Typed, error) {
_, err := os.Stat(out)
if os.IsNotExist(err) {
return ensureComic(out, id)
} else if err == nil {
data, err := os.ReadFile(filepath.Join(out, "info.json"))
if err != nil {
return nil, err
}
return typed.Json(data)
}
return nil, err
}