Allow editing of individual sections

main.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"strconv"
 	"strings"
 )
 
@@ -123,6 +124,16 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 	indexPath := filepath.Join(fsPath, "index.md")
 	rawMD, _ := os.ReadFile(indexPath)
 
+	// Determine section index (-1 = whole page).
+	sectionIndex := -1
+	if editMode {
+		if s := r.URL.Query().Get("section"); s != "" {
+			if n, err := strconv.Atoi(s); err == nil && n >= 0 {
+				sectionIndex = n
+			}
+		}
+	}
+
 	var rendered template.HTML
 	if len(rawMD) > 0 && !editMode {
 		rendered = renderMarkdown(rawMD)
@@ -152,13 +163,22 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 		specialContent = special.Content
 	}
 
+	rawContent := string(rawMD)
+	if editMode && sectionIndex >= 0 {
+		sections := splitSections(rawMD)
+		if sectionIndex < len(sections) {
+			rawContent = string(sections[sectionIndex])
+		}
+	}
+
 	data := pageData{
 		Title:          title,
 		Crumbs:         buildCrumbs(urlPath),
 		CanEdit:        true,
 		EditMode:       editMode,
+		SectionIndex:   sectionIndex,
 		PostURL:        urlPath,
-		RawContent:     string(rawMD),
+		RawContent:     rawContent,
 		Content:        rendered,
 		Entries:        entries,
 		SpecialContent: specialContent,
@@ -177,6 +197,23 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 	}
 	content := r.FormValue("content")
 	indexPath := filepath.Join(fsPath, "index.md")
+
+	// If a section index was submitted, splice the edited section back into
+	// the full file rather than replacing the whole document.
+	if s := r.FormValue("section"); s != "" {
+		sectionIndex, err := strconv.Atoi(s)
+		if err != nil || sectionIndex < 0 {
+			http.Error(w, "bad section", http.StatusBadRequest)
+			return
+		}
+		rawMD, _ := os.ReadFile(indexPath)
+		sections := splitSections(rawMD)
+		if sectionIndex < len(sections) {
+			sections[sectionIndex] = []byte(content)
+		}
+		content = string(joinSections(sections))
+	}
+
 	if strings.TrimSpace(content) == "" {
 		if err := os.Remove(indexPath); err != nil && !os.IsNotExist(err) {
 			http.Error(w, "delete failed: "+err.Error(), http.StatusInternalServerError)