Refactor: Isolata in un pacchetto autonomo la struct che gestisce il registro degli articoli

articles/article.go

@@ -0,0 +1,113 @@
+package articles
+
+import (
+	"bytes"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/phc-dm/phc-server/config"
+	"gopkg.in/yaml.v3"
+)
+
+type Article struct {
+	Id          string
+	Title       string
+	Description string
+	Tags        []string
+	PublishDate time.Time
+
+	ArticlePath    string
+	markdownSource string
+	renderedHTML   string
+}
+
+func (article *Article) HasTag(tag string) bool {
+	for _, t := range article.Tags {
+		if t == tag {
+			return true
+		}
+	}
+
+	return false
+}
+
+func NewArticle(articlePath string) (*Article, error) {
+	article := &Article{
+		ArticlePath: articlePath,
+	}
+
+	err := article.load()
+	if err != nil {
+		return nil, err
+	}
+
+	return article, nil
+}
+
+func trimAll(vs []string) []string {
+	r := []string{}
+	for _, v := range vs {
+		r = append(r, strings.TrimSpace(v))
+	}
+	return r
+}
+
+func (article *Article) load() error {
+	fileBytes, err := os.ReadFile(article.ArticlePath)
+	if err != nil {
+		return err
+	}
+
+	source := string(fileBytes)
+
+	// TODO: Ehm bugia pare che esista "https://github.com/yuin/goldmark-meta" però non penso valga la pena aggiungerlo
+	parts := strings.SplitN(source, "---", 3)[1:]
+
+	frontMatterSource := parts[0]
+	markdownSource := parts[1]
+
+	var frontMatter struct {
+		Id          string `yaml:"id"`
+		Title       string `yaml:"title"`
+		Description string `yaml:"description"`
+		Tags        string `yaml:"tags"`
+		PublishDate string `yaml:"publish_date"`
+	}
+	if err := yaml.Unmarshal([]byte(frontMatterSource), &frontMatter); err != nil {
+		return err
+	}
+
+	publishDate, err := time.Parse("2006/01/02 15:04", frontMatter.PublishDate)
+	if err != nil {
+		return err
+	}
+
+	article.Id = frontMatter.Id
+	article.Title = frontMatter.Title
+	article.Description = frontMatter.Description
+	article.Tags = trimAll(strings.Split(frontMatter.Tags, ","))
+	article.PublishDate = publishDate
+
+	article.markdownSource = markdownSource
+	article.renderedHTML = ""
+
+	return nil
+}
+
+func (article *Article) Render() (string, error) {
+	if config.Mode == "development" {
+		article.load()
+	}
+
+	if article.renderedHTML == "" {
+		var buf bytes.Buffer
+		if err := articleMarkdown.Convert([]byte(article.markdownSource), &buf); err != nil {
+			return "", err
+		}
+
+		article.renderedHTML = buf.String()
+	}
+
+	return article.renderedHTML, nil
+}

articles/articles.go

@@ -0,0 +1,77 @@
+package articles
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"sort"
+)
+
+type Registry struct {
+	RootPath     string
+	ArticleCache map[string]*Article
+}
+
+func NewRegistry(rootPath string) *Registry {
+	return &Registry{
+		rootPath,
+		map[string]*Article{},
+	}
+}
+
+func (registry *Registry) loadArticles() error {
+	entries, err := os.ReadDir(registry.RootPath)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			article, err := NewArticle(path.Join(registry.RootPath, entry.Name()))
+			if err != nil {
+				return err
+			}
+
+			registry.ArticleCache[article.Id] = article
+		}
+	}
+
+	return nil
+}
+
+func (registry *Registry) GetArticle(id string) (*Article, error) {
+	article, present := registry.ArticleCache[id]
+	if !present {
+		err := registry.loadArticles()
+		if err != nil {
+			return nil, err
+		}
+
+		article, present := registry.ArticleCache[id]
+		if !present {
+			return nil, fmt.Errorf(`no article with id "%s"`, id)
+		}
+
+		return article, nil
+	}
+
+	return article, nil
+}
+
+func (registry *Registry) GetArticles() ([]*Article, error) {
+	err := registry.loadArticles()
+	if err != nil {
+		return nil, err
+	}
+
+	articles := []*Article{}
+	for _, article := range registry.ArticleCache {
+		articles = append(articles, article)
+	}
+
+	sort.Slice(articles, func(i, j int) bool {
+		return articles[i].PublishDate.After(articles[j].PublishDate)
+	})
+
+	return articles, nil
+}

articles/markdown.go

@@ -0,0 +1,60 @@
+package articles
+
+import (
+	"fmt"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/util"
+
+	chromahtml "github.com/alecthomas/chroma/formatters/html"
+	mathjax "github.com/litao91/goldmark-mathjax"
+	highlighting "github.com/yuin/goldmark-highlighting"
+)
+
+var articleMarkdown goldmark.Markdown
+
+// https://github.com/yuin/goldmark-highlighting/blob/9216f9c5aa010c549cc9fc92bb2593ab299f90d4/highlighting_test.go#L27
+func customCodeBlockWrapper(w util.BufWriter, c highlighting.CodeBlockContext, entering bool) {
+	lang, ok := c.Language()
+	if entering {
+		if ok {
+			w.WriteString(fmt.Sprintf(`<pre class="%s"><code>`, lang))
+			return
+		}
+		w.WriteString("<pre><code>")
+	} else {
+		if ok {
+			w.WriteString("</pre></code>")
+			return
+		}
+		w.WriteString("</pre></code>")
+	}
+}
+
+func init() {
+	articleMarkdown = goldmark.New(
+		goldmark.WithExtensions(
+			extension.GFM,
+			extension.Typographer,
+			// Questo pacchetto ha un nome stupido perché in realtà si occupa solo del parsing lato server del Markdown mentre lato client usiamo KaTeX.
+			mathjax.NewMathJax(),
+			highlighting.NewHighlighting(
+				highlighting.WithStyle("github"),
+				highlighting.WithWrapperRenderer(customCodeBlockWrapper),
+				highlighting.WithFormatOptions(
+					chromahtml.PreventSurroundingPre(true),
+				),
+			),
+		),
+		goldmark.WithParserOptions(
+			parser.WithAutoHeadingID(),
+		),
+		goldmark.WithRendererOptions(
+			html.WithHardWraps(),
+			html.WithXHTML(),
+		),
+	)
+}