Add RSS/Sitemap handling.

server/utils/article_to_description.go

@@ -0,0 +1,55 @@
+package utils
+
+import (
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/html"
+	"github.com/gomarkdown/markdown/parser"
+	"github.com/k3a/html2text"
+	"strings"
+)
+
+func ArticleToDescription(article string, maxLength int) string {
+	if maxLength < 3 {
+		maxLength = 3
+	}
+	htmlContent := mdToHTML([]byte(article))
+	plain := html2text.HTML2Text(string(htmlContent))
+	plain = strings.TrimSpace(plain)
+	plain = mergeSpaces(plain)
+	if len([]rune(plain)) > maxLength {
+		plain = string([]rune(plain)[:(maxLength-3)]) + "..."
+	}
+	return plain
+}
+
+func mergeSpaces(str string) string {
+	// Replace multiple spaces with a single space
+	builder := strings.Builder{}
+	for i, r := range str {
+		if r == '\t' || r == '\r' {
+			continue
+		}
+		if r == ' ' || r == '\n' {
+			if i > 0 && str[i-1] != ' ' && str[i-1] != '\n' {
+				builder.WriteRune(' ')
+			}
+		} else {
+			builder.WriteRune(r)
+		}
+	}
+	return builder.String()
+}
+
+func mdToHTML(md []byte) []byte {
+	// create Markdown parser with extensions
+	extensions := parser.CommonExtensions | parser.NoEmptyLineBeforeBlock | parser.MathJax
+	p := parser.NewWithExtensions(extensions)
+	doc := p.Parse(md)
+
+	// create HTML renderer with extensions
+	htmlFlags := html.CommonFlags | html.HrefTargetBlank
+	opts := html.RendererOptions{Flags: htmlFlags}
+	renderer := html.NewRenderer(opts)
+
+	return markdown.Render(doc, renderer)
+}