Simple blogging system written in Go https://goblog.app
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

207 lines
5.4 KiB

package main
import (
"bytes"
"html/template"
marktag "git.jlel.se/jlelse/goldmark-mark"
chromahtml "github.com/alecthomas/chroma/formatters/html"
"github.com/yuin/goldmark"
emoji "github.com/yuin/goldmark-emoji"
highlighting "github.com/yuin/goldmark-highlighting"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/extension"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/renderer/html"
"github.com/yuin/goldmark/util"
)
func (a *goBlog) initMarkdown() {
if a.md != nil && a.absoluteMd != nil && a.titleMd != nil {
// Already initialized
return
}
defaultGoldmarkOptions := []goldmark.Option{
goldmark.WithRendererOptions(
html.WithUnsafe(),
),
goldmark.WithParserOptions(
parser.WithAutoHeadingID(),
),
goldmark.WithExtensions(
extension.Table,
extension.Strikethrough,
extension.Footnote,
extension.Typographer,
extension.Linkify,
marktag.Mark,
emoji.Emoji,
highlighting.NewHighlighting(
highlighting.WithCustomStyle(chromaGoBlogStyle),
highlighting.WithFormatOptions(
chromahtml.ClassPrefix("c-"),
chromahtml.WithClasses(true),
),
),
),
}
publicAddress := ""
if srv := a.cfg.Server; srv != nil {
publicAddress = srv.PublicAddress
}
a.md = goldmark.New(append(defaultGoldmarkOptions, goldmark.WithExtensions(&customExtension{
absoluteLinks: false,
publicAddress: publicAddress,
}))...)
a.absoluteMd = goldmark.New(append(defaultGoldmarkOptions, goldmark.WithExtensions(&customExtension{
absoluteLinks: true,
publicAddress: publicAddress,
}))...)
a.titleMd = goldmark.New(
goldmark.WithParser(
// Override, no need for special Markdown parsers
parser.NewParser(
parser.WithBlockParsers(
util.Prioritized(parser.NewParagraphParser(), 1000)),
parser.WithInlineParsers(),
parser.WithParagraphTransformers(),
),
),
goldmark.WithExtensions(
extension.Typographer,
emoji.Emoji,
),
)
}
func (a *goBlog) renderMarkdown(source string, absoluteLinks bool) (rendered []byte, err error) {
var buffer bytes.Buffer
if absoluteLinks {
err = a.absoluteMd.Convert([]byte(source), &buffer)
} else {
err = a.md.Convert([]byte(source), &buffer)
}
return buffer.Bytes(), err
}
func (a *goBlog) renderMarkdownAsHTML(source string, absoluteLinks bool) (rendered template.HTML, err error) {
b, err := a.renderMarkdown(source, absoluteLinks)
if err != nil {
return "", err
}
return template.HTML(b), nil
}
func (a *goBlog) safeRenderMarkdownAsHTML(source string) template.HTML {
h, _ := a.renderMarkdownAsHTML(source, false)
return h
}
func (a *goBlog) renderText(s string) string {
if s == "" {
return ""
}
h, err := a.renderMarkdown(s, false)
if err != nil {
return ""
}
return htmlText(string(h))
}
func (a *goBlog) renderMdTitle(s string) string {
if s == "" {
return ""
}
var buffer bytes.Buffer
err := a.titleMd.Convert([]byte(s), &buffer)
if err != nil {
return ""
}
return htmlText(buffer.String())
}
// Extensions etc...
// Links
type customExtension struct {
absoluteLinks bool
publicAddress string
}
func (l *customExtension) Extend(m goldmark.Markdown) {
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(&customRenderer{
absoluteLinks: l.absoluteLinks,
publicAddress: l.publicAddress,
}, 500),
))
}
type customRenderer struct {
absoluteLinks bool
publicAddress string
}
func (c *customRenderer) RegisterFuncs(r renderer.NodeRendererFuncRegisterer) {
r.Register(ast.KindLink, c.renderLink)
r.Register(ast.KindImage, c.renderImage)
}
func (c *customRenderer) renderLink(w util.BufWriter, _ []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
if entering {
n := node.(*ast.Link)
_, _ = w.WriteString("<a href=\"")
// Make URL absolute if it's relative
newDestination := util.URLEscape(n.Destination, true)
if c.absoluteLinks && c.publicAddress != "" && bytes.HasPrefix(newDestination, []byte("/")) {
_, _ = w.Write(util.EscapeHTML([]byte(c.publicAddress)))
}
_, _ = w.Write(util.EscapeHTML(newDestination))
_, _ = w.WriteRune('"')
// Open external links (links that start with "http") in new tab
if isAbsoluteURL(string(n.Destination)) {
_, _ = w.WriteString(` target="_blank" rel="noopener"`)
}
// Title
if n.Title != nil {
_, _ = w.WriteString(" title=\"")
_, _ = w.Write(n.Title)
_, _ = w.WriteRune('"')
}
_, _ = w.WriteRune('>')
} else {
_, _ = w.WriteString("</a>")
}
return ast.WalkContinue, nil
}
func (c *customRenderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
if !entering {
return ast.WalkContinue, nil
}
n := node.(*ast.Image)
// Make URL absolute if it's relative
destination := util.URLEscape(n.Destination, true)
if c.absoluteLinks && c.publicAddress != "" && bytes.HasPrefix(destination, []byte("/")) {
destination = util.EscapeHTML(append([]byte(c.publicAddress), destination...))
} else {
destination = util.EscapeHTML(destination)
}
_, _ = w.WriteString("<a href=\"")
_, _ = w.Write(destination)
_, _ = w.WriteString("\">")
_, _ = w.WriteString("<img src=\"")
_, _ = w.Write(destination)
_, _ = w.WriteString("\" alt=\"")
_, _ = w.Write(util.EscapeHTML(n.Text(source)))
_ = w.WriteByte('"')
_, _ = w.WriteString(" loading=\"lazy\"")
if n.Title != nil {
_, _ = w.WriteString(" title=\"")
_, _ = w.Write(n.Title)
_ = w.WriteByte('"')
}
_, _ = w.WriteString("></a>")
return ast.WalkSkipChildren, nil
}