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)
+}

server/utils/rss.go

@@ -0,0 +1,49 @@
+package utils
+
+import (
+	"github.com/gofiber/fiber/v3/log"
+	"net/url"
+	"nysoure/server/model"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+const (
+	RssFileName = "rss.xml"
+)
+
+func GenerateRss(baseURL string, resources []model.Resource) {
+	path := filepath.Join(GetStoragePath(), RssFileName)
+	builder := strings.Builder{}
+	builder.WriteString(`<?xml version="1.0" encoding="UTF-8"?>`)
+	builder.WriteRune('\n')
+	builder.WriteString(`<rss version="2.0">`)
+	builder.WriteRune('\n')
+	builder.WriteString(`<channel>`)
+	builder.WriteRune('\n')
+	for _, resource := range resources {
+		builder.WriteString("  <item>\n")
+		builder.WriteString("    <title>")
+		builder.WriteString(url.PathEscape(resource.Title))
+		builder.WriteString("</title>\n")
+		builder.WriteString("    <link>")
+		builder.WriteString(baseURL + "/resources/" + strconv.Itoa(int(resource.ID)))
+		builder.WriteString("</link>\n")
+		builder.WriteString("    <description>")
+		builder.WriteString(url.PathEscape(ArticleToDescription(resource.Article, 255)))
+		builder.WriteString("</description>\n")
+		builder.WriteString("    <pubDate>")
+		builder.WriteString(resource.UpdatedAt.Format("Mon, 02 Jan 2006 15:04:05 MST"))
+		builder.WriteString("</pubDate>\n")
+		builder.WriteString("  </item>\n")
+	}
+	builder.WriteString(`</channel>`)
+	builder.WriteRune('\n')
+	builder.WriteString(`</rss>`)
+	data := builder.String()
+	if err := os.WriteFile(path, []byte(data), 0644); err != nil {
+		log.Error("failed to write RSS file", err)
+	}
+}

server/utils/site_map.go

@@ -0,0 +1,39 @@
+package utils
+
+import (
+	"fmt"
+	"github.com/gofiber/fiber/v3/log"
+	"nysoure/server/model"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const (
+	SiteMapFileName = "sitemap.xml"
+)
+
+func GenerateSiteMap(baseURL string, resources []model.Resource) {
+	path := filepath.Join(GetStoragePath(), SiteMapFileName)
+	builder := strings.Builder{}
+	builder.WriteString(`<?xml version="1.0" encoding="UTF-8"?>`)
+	builder.WriteRune('\n')
+	builder.WriteString(`<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">`)
+	builder.WriteRune('\n')
+	for _, resource := range resources {
+		builder.WriteString("  <url>\n")
+		builder.WriteString("    <loc>")
+		builder.WriteString(fmt.Sprintf("%s/resources/%d", baseURL, resource.ID))
+		builder.WriteString("</loc>\n")
+		builder.WriteString("    <lastmod>")
+		builder.WriteString(resource.UpdatedAt.Format("2006-01-02"))
+		builder.WriteString("</lastmod>\n")
+		builder.WriteString("  </url>\n")
+	}
+	builder.WriteString(`</urlset>`)
+	builder.WriteRune('\n')
+	data := builder.String()
+	if err := os.WriteFile(path, []byte(data), 0644); err != nil {
+		log.Error("failed to write site map file", err)
+	}
+}