Add !embed(...) syntax

src/parsing/bbcode.go

@@ -1,7 +1,6 @@
 package parsing
 
 import (
-	"fmt"
 	"strings"
 
 	"github.com/yuin/goldmark"
@@ -34,9 +33,7 @@ func (s bParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) g
 	// link.Protocol = protocol
 	// return link
 
-	lineBytes, segment := block.PeekLine()
-	fmt.Printf("line: %s\n", string(lineBytes))
-	fmt.Printf("segment: %#v\n", segment)
+	lineBytes, _ := block.PeekLine()
 
 	line := string(lineBytes)
 

src/parsing/embed.go

@@ -0,0 +1,152 @@
+package parsing
+
+import (
+	"regexp"
+
+	"github.com/yuin/goldmark"
+	gast "github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+var (
+	REEmbedTag = regexp.MustCompile(`^!embed\((?P<url>.+?)\)`)
+
+	REYoutubeLong  = regexp.MustCompile(`^https://www\.youtube\.com/watch?.*v=(?P<vid>[a-zA-Z0-9_-]{11})`)
+	REYoutubeShort = regexp.MustCompile(`^https://youtu\.be/(?P<vid>[a-zA-Z0-9_-]{11})`)
+	REVimeo        = regexp.MustCompile(`^https://vimeo\.com/(?P<vid>\d+)`)
+)
+
+// ----------------------
+// Parser and delimiters
+// ----------------------
+
+type embedParser struct{}
+
+// TODO: Make this a block parser
+func NewEmbedParser() parser.InlineParser {
+	return embedParser{}
+}
+
+func (s embedParser) Trigger() []byte {
+	return []byte{'!'}
+}
+
+func (s embedParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) gast.Node {
+	restOfLine, _ := block.PeekLine()
+	urlMatch := REEmbedTag.FindSubmatch(restOfLine)
+	if urlMatch == nil {
+		return nil
+	}
+	url := urlMatch[REEmbedTag.SubexpIndex("url")]
+
+	html := ""
+	if ytLongMatch := extract(REYoutubeLong, url, "vid"); ytLongMatch != nil {
+		html = makeYoutubeEmbed(string(ytLongMatch))
+	} else if ytShortMatch := extract(REYoutubeShort, url, "vid"); ytShortMatch != nil {
+		html = makeYoutubeEmbed(string(ytShortMatch))
+	} else if vimeoMatch := extract(REVimeo, url, "vid"); vimeoMatch != nil {
+		html = `
+<div class="mw6">
+	<div class="aspect-ratio aspect-ratio--16x9">
+		<iframe class="aspect-ratio--object" src="https://player.vimeo.com/video/` + string(vimeoMatch) + `" frameborder="0" allow="fullscreen; picture-in-picture" allowfullscreen></iframe>
+	</div>
+</div>`
+	}
+
+	if html == "" {
+		return nil
+	}
+
+	block.Advance(len(urlMatch[0]))
+	return NewEmbed(html)
+}
+
+func extract(re *regexp.Regexp, src []byte, subexpName string) []byte {
+	m := re.FindSubmatch(src)
+	if m == nil {
+		return nil
+	}
+	return m[re.SubexpIndex(subexpName)]
+}
+
+func makeYoutubeEmbed(vid string) string {
+	return `
+<div class="mw6">
+	<div class="aspect-ratio aspect-ratio--16x9">
+		<iframe class="aspect-ratio--object" src="https://www.youtube-nocookie.com/embed/` + vid + `" frameborder="0" allowfullscreen></iframe>
+	</div>
+</div>`
+}
+
+// ----------------------
+// AST node
+// ----------------------
+
+type EmbedNode struct {
+	gast.BaseBlock
+	HTML string
+}
+
+func (n *EmbedNode) Dump(source []byte, level int) {
+	gast.DumpHelper(n, source, level, nil, nil)
+}
+
+var KindEmbed = gast.NewNodeKind("Embed")
+
+func (n *EmbedNode) Kind() gast.NodeKind {
+	return KindEmbed
+}
+
+func NewEmbed(HTML string) gast.Node {
+	return &EmbedNode{
+		HTML: HTML,
+	}
+}
+
+// ----------------------
+// Renderer
+// ----------------------
+
+type EmbedHTMLRenderer struct {
+	html.Config
+}
+
+func NewEmbedHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
+	r := &EmbedHTMLRenderer{
+		Config: html.NewConfig(),
+	}
+	for _, opt := range opts {
+		opt.SetHTMLOption(&r.Config)
+	}
+	return r
+}
+
+func (r *EmbedHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	reg.Register(KindEmbed, r.renderEmbed)
+}
+
+func (r *EmbedHTMLRenderer) renderEmbed(w util.BufWriter, source []byte, n gast.Node, entering bool) (gast.WalkStatus, error) {
+	if entering {
+		w.WriteString(n.(*EmbedNode).HTML)
+	}
+	return gast.WalkSkipChildren, nil
+}
+
+// ----------------------
+// Extension
+// ----------------------
+
+type EmbedExtension struct{}
+
+func (e EmbedExtension) Extend(m goldmark.Markdown) {
+	m.Parser().AddOptions(parser.WithInlineParsers(
+		util.Prioritized(NewEmbedParser(), 500),
+	))
+	m.Renderer().AddOptions(renderer.WithNodeRenderers(
+		util.Prioritized(NewEmbedHTMLRenderer(), 500),
+	))
+}

src/parsing/parsing.go

@@ -91,7 +91,7 @@ func tokenizeBBCode(input string) []token {
 }
 
 var md = goldmark.New(
-	goldmark.WithExtensions(extension.GFM, SpoilerExtension{}, bTag{}),
+	goldmark.WithExtensions(extension.GFM, SpoilerExtension{}, EmbedExtension{}, bTag{}),
 )
 
 func ParsePostInput(source string) string {

src/parsing/spoilers.go

@@ -72,7 +72,7 @@ func (n *SpoilerNode) Kind() gast.NodeKind {
 	return KindSpoiler
 }
 
-func NewSpoiler() *SpoilerNode {
+func NewSpoiler() gast.Node {
 	return &SpoilerNode{}
 }