Add Markdown render function

posts/render.go

@@ -0,0 +1,37 @@
+package posts
+
+import (
+	"github.com/microcosm-cc/bluemonday"
+	"github.com/writeas/saturday"
+	"regexp"
+)
+
+var (
+	blockReg    = regexp.MustCompile("<(ul|ol|blockquote)>\n")
+	endBlockReg = regexp.MustCompile("</([a-z]+)>\n</(ul|ol|blockquote)>")
+)
+
+func ApplyMarkdown(data []byte) string {
+	mdExtensions := 0 |
+		blackfriday.EXTENSION_TABLES |
+		blackfriday.EXTENSION_FENCED_CODE |
+		blackfriday.EXTENSION_AUTOLINK |
+		blackfriday.EXTENSION_STRIKETHROUGH |
+		blackfriday.EXTENSION_SPACE_HEADERS |
+		blackfriday.EXTENSION_HEADER_IDS
+	htmlFlags := 0 |
+		blackfriday.HTML_USE_SMARTYPANTS |
+		blackfriday.HTML_SMARTYPANTS_DASHES
+
+	// Generate Markdown
+	md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions)
+	// Strip out bad HTML
+	policy := bluemonday.UGCPolicy()
+	policy.AllowAttrs("class", "id").Globally()
+	outHTML := string(policy.SanitizeBytes(md))
+	// Strip newlines on certain block elements that render with them
+	outHTML = blockReg.ReplaceAllString(outHTML, "<$1>")
+	outHTML = endBlockReg.ReplaceAllString(outHTML, "</$1></$2>")
+
+	return outHTML
+}