Initial MVP: Go + templ Tolino-optimized ebook library scaffold

internal/web/handlers.go

@@ -0,0 +1,91 @@
+package web
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"path/filepath"
+	"strings"
+
+	"github.com/arnef/ebooks/internal/library"
+	"github.com/arnef/ebooks/views"
+)
+
+type Handler struct {
+	lib *library.Service
+}
+
+func NewHandler(lib *library.Service) *Handler {
+	return &Handler{lib: lib}
+}
+
+func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
+	mux.HandleFunc("GET /", h.listBooks)
+	mux.HandleFunc("GET /book/{id}", h.bookDetails)
+	mux.HandleFunc("GET /download/{id}", h.downloadBook)
+	mux.Handle("GET /static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
+}
+
+func (h *Handler) listBooks(w http.ResponseWriter, r *http.Request) {
+	books, err := h.lib.ListBooks()
+	if err != nil {
+		http.Error(w, "failed to load books", http.StatusInternalServerError)
+		return
+	}
+	render(w, r.Context(), views.IndexPage(books))
+}
+
+func (h *Handler) bookDetails(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if id == "" {
+		http.NotFound(w, r)
+		return
+	}
+
+	book, err := h.lib.FindBook(id)
+	if err != nil {
+		http.Error(w, "failed to load book", http.StatusInternalServerError)
+		return
+	}
+	if book == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	render(w, r.Context(), views.BookPage(*book))
+}
+
+func (h *Handler) downloadBook(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if id == "" {
+		http.NotFound(w, r)
+		return
+	}
+
+	book, err := h.lib.FindBook(id)
+	if err != nil {
+		http.Error(w, "failed to load book", http.StatusInternalServerError)
+		return
+	}
+	if book == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	cleanBase := filepath.Clean(h.lib.BooksDir())
+	cleanPath := filepath.Clean(book.Path)
+	if !strings.HasPrefix(cleanPath, cleanBase+string(filepath.Separator)) && cleanPath != cleanBase {
+		http.Error(w, "invalid file path", http.StatusBadRequest)
+		return
+	}
+
+	w.Header().Set("Content-Disposition", "attachment; filename=\""+book.Filename+"\"")
+	http.ServeFile(w, r, cleanPath)
+}
+
+func render(w http.ResponseWriter, ctx context.Context, page interface{ Render(context.Context, http.ResponseWriter) error }) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if err := page.Render(ctx, w); err != nil && !errors.Is(err, context.Canceled) {
+		http.Error(w, "render failed", http.StatusInternalServerError)
+	}
+}