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package main
import (
"crypto/md5"
"crypto/rand"
"encoding/hex"
"encoding/json"
"flag"
"fmt"
"html/template"
"io"
"io/ioutil"
"net/url"
"os"
"strings"
"unicode"
"github.com/russross/blackfriday"
"gopkg.in/yaml.v2"
)
type Post struct {
Id string `yaml:"id"`
Title string `yaml:"title"`
URL string `yaml:"url"`
Content string `yaml:"content"`
Tags []string `yaml:"tags"`
Date string `yaml:"date"`
Type string `yaml:"type"`
}
var flags struct {
writeBack bool
hashIds bool
reverse bool
css string
title string
}
var dataPath string = "blog.yaml"
var defaultStyle = `
article {
margin-bottom: 2em;
}
article header {
display: flex;
align-items: center;
}
article h1 {
margin: 0;
}
article header .permalink {
margin-left: 0.1em;
text-decoration: none;
color: #555;
visibility: hidden;
}
article header:hover .permalink {
visibility: visible;
}
article time {
margin-left: 1em;
color: #666;
}
article img {
max-width: 80vw;
max-height: 50vh;
}
article .tags {
list-style-type: none;
padding: 0;
}
article .tags .tag-link {
float: left;
color: black;
margin-right: 0.5em;
}
article .tags .tag-link:visited {
color: #555;
}
article.does-not-match {
display: none;
}
`
func init() {
flag.BoolVar(&flags.writeBack, "write-back", false, "Rewrite the YAML file with the generated ids")
flag.BoolVar(&flags.hashIds, "hash-ids", false, "Use hash-based post ids")
flag.BoolVar(&flags.reverse, "reverse", false, "Reverse the order of the articles in the file")
flag.StringVar(&flags.css, "css", defaultStyle, "Custom `css` styles to use")
flag.StringVar(&flags.title, "title", "A blog", "Custom `title` to use")
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [flags] [<blog.yaml> [<blog.html>]]\n\n", os.Args[0])
flag.PrintDefaults()
}
}
func main() {
flag.Parse()
if flag.NArg() > 0 {
dataPath = flag.Arg(0)
}
f, err := os.Open(dataPath)
if err != nil {
exit(err)
}
defer f.Close()
out := os.Stdout
if flag.NArg() > 1 {
out, err = os.Create(flag.Arg(1))
if err != nil {
exit(err)
}
}
data, err := ioutil.ReadAll(f)
if err != nil {
exit(err)
}
var posts []Post
err = yaml.Unmarshal(data, &posts)
if err != nil {
exit(err)
}
fmt.Fprintf(out, `<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>%s</title>
<style>%s</style>
</head>
<body>
`, flags.title, flags.css)
if flags.reverse {
l := len(posts)
reversePosts := make([]Post, l)
for i := 0; i < l; i++ {
reversePosts[i] = posts[l-i-1]
}
posts = reversePosts
}
for i, post := range posts {
if post.Id == "" {
posts[i].Id = generateId(post)
post = posts[i]
}
var err error
switch post.Type {
case "shell":
err = shellTmpl.Execute(out, post)
case "link":
err = linkTmpl.Execute(out, post)
case "image":
err = imageTmpl.Execute(out, post)
case "song":
err = songTmpl.Execute(out, post)
case "text":
err = textTmpl.Execute(out, post)
case "video":
u, err := url.Parse(post.URL)
if err != nil {
exit(fmt.Errorf("invalid video url '%s'", post.URL))
}
id := u.Query().Get("v")
if (u.Host != "youtube.com" && u.Host != "www.youtube.com") || id == "" {
exit(fmt.Errorf("unsupported video url '%s'", post.URL))
}
post.URL = id
err = videoTmpl.Execute(out, post)
default:
fmt.Fprintf(os.Stderr, "Error: no output for type '%s'\n", post.Type)
os.Exit(1)
}
if err != nil {
exit(err)
}
}
fmt.Fprintf(out, `
<script>
window.addEventListener("click", function(ev) {
if (ev.target.classList.contains("tag-link")) {
if (ev.target.href == "") {
return;
}
var u = new URL(ev.target.href);
if (!u.hash.startsWith("#tag:")) {
return;
}
var tag = u.hash.substr(5);
filterTag(tag);
}
})
function filterTag(tag) {
var articles = document.querySelectorAll("article");
for (var i = 0; i < articles.length; i++) {
var article = articles[i];
var matches = false;
if (article && 'tags' in article.dataset) {
var tags = JSON.parse(article.dataset.tags);
for (var j = 0; j < tags.length; j++) {
if (tags[j] == tag) {
matches = true;
break;
}
}
}
if (!matches) {
article.classList.add("does-not-match");
}
}
}
</script>`)
fmt.Fprintf(out, "\n</body>\n</html>\n")
out.Close()
if flags.writeBack {
dataOut, err := yaml.Marshal(posts)
if err != nil {
exit(err)
}
ioutil.WriteFile(dataPath, dataOut, 0664)
}
}
var funcs = template.FuncMap{
"markdown": func(markdown string) template.HTML {
return template.HTML(blackfriday.MarkdownCommon([]byte(markdown)))
},
"safe_url": func(s string) template.URL {
return template.URL(s)
},
"json": func(v interface{}) (string, error) {
buf, err := json.Marshal(v)
return string(buf), err
},
}
var baseTmpl = template.Must(template.New("base").
Funcs(funcs).Parse(`
{{ define "title" }}
<header>
{{- if .Title }}
<h1>{{ .Title }}</h1>{{ end }}
<a class="permalink" href="#{{ .Id }}">∞</a>
{{- if .Date }}
<time>{{ .Date }}</time>{{ end }}
</header>
{{ end }}
{{ define "tags" }}
<ul class="tags">
{{- range . }}
<li><a class="tag-link" href="#tag:{{ safe_url . }}">{{ . }}</a></li>
{{ end -}}
</ul>
{{ end }}
`))
var shellTmpl = template.Must(baseTmpl.New("shell").
Funcs(funcs).Parse(`
<article id="{{ .Id }}" class="shell">
<header>
<h1><code class="language-shell">{{ .Title }}</code></h1>
<a class="permalink" href="#{{ .Id }}">∞</a>
{{- if .Date }}
<time>{{ .Date }}</time>{{ end }}
</header>
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
</article>
`))
var linkTmpl = template.Must(baseTmpl.New("link").
Funcs(funcs).Parse(`
<article id="{{ .Id }}" class="link">
<header>
<h1><a href="{{ .URL }}">{{ .Title }}</a></h1>
<a class="permalink" href="#{{ .Id }}">∞</a>
{{- if .Date }}
<time>{{ .Date }}</time>{{ end }}
</header>
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
</article>
`))
var imageTmpl = template.Must(baseTmpl.New("image").
Funcs(funcs).Parse(`
<article id="{{ .Id }}" class="image">
{{- template "title" . }}
<img src="{{ safe_url .URL }}" />
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
</article>
`))
var songTmpl = template.Must(baseTmpl.New("song").
Funcs(funcs).Parse(`
<article id="{{ .Id }}" class="song">
{{- template "title" . }}
<audio src="{{ safe_url .URL }}" controls>
Your browser can't play {{ .URL }}.
</audio>
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
</article>
`))
var textTmpl = template.Must(baseTmpl.New("text").
Funcs(funcs).Parse(`
<article id="{{ .Id }}" class="text" {{- if .Tags }} data-tags="{{ json .Tags }}"{{ end }}>
{{- template "title" . }}
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
<footer>
{{ template "tags" .Tags }}
</footer>
</article>
`))
var videoTmpl = template.Must(baseTmpl.Parse(`
<article id="{{ .Id }}" class="video">
{{- template "title" . }}
<iframe width="560" height="315" src="https://www.youtube.com/embed/{{ .URL }}" frameborder="0" allowfullscreen></iframe>
{{- if .Content }}
{{ markdown .Content }}
{{- end -}}
</article>
`))
func exit(err error) {
fmt.Fprintf(os.Stderr, "Error: %s\n", err)
os.Exit(1)
}
func generateId(p Post) string {
if flags.hashIds {
return hashId(p)
}
return slugId(p)
}
func hashId(p Post) string {
h := md5.New()
io.WriteString(h, p.Title)
io.WriteString(h, p.Content)
io.WriteString(h, p.Type)
return hex.EncodeToString(h.Sum(nil))
}
func randomId() string {
buf := make([]byte, 16)
_, err := rand.Read(buf)
if err != nil {
panic(err)
}
return hex.EncodeToString(buf)
}
var usedSlugs = map[string]int{}
func slugId(p Post) string {
slug := toSlug(p.Title)
n, ok := usedSlugs[slug]
if ok {
n += 1
} else {
n = 1
}
usedSlugs[slug] = n
if slug != "" && n == 1 {
return slug
} else if slug == "" {
return fmt.Sprintf("%d", n)
}
return fmt.Sprintf("%s-%d", slug, n)
}
func toSlug(s string) string {
lastChar := ' '
s = strings.Map(func(ch rune) rune {
var newChar rune
switch {
case unicode.IsLetter(ch) || unicode.IsDigit(ch):
newChar = unicode.ToLower(ch)
default:
if lastChar == '-' {
return -1
}
newChar = '-'
}
lastChar = newChar
return newChar
}, s)
return strings.Trim(s, "-")
}
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