implement frontend routing

Dockerfile

@@ -22,6 +22,6 @@ RUN go build \
 FROM gcr.io/distroless/base:latest
 WORKDIR /root
 COPY --from=build /app/pasty .
-COPY web ./web/
+COPY internal/web/web ./web/
 EXPOSE 8080
 CMD ["./pasty"]

internal/web/frontend_server.go

@@ -0,0 +1,77 @@
+package web
+
+import (
+	"embed"
+	"errors"
+	"io"
+	"io/fs"
+	"mime"
+	"net/http"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+//go:embed frontend/*
+var frontend embed.FS
+
+func frontendHandler(notFoundHandler http.HandlerFunc) http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		path := strings.TrimSpace(strings.TrimSuffix(request.URL.Path, "/"))
+
+		isFirstLevel := strings.Count(path, "/") <= 1
+
+		file, err := frontend.Open(filepath.Join("frontend", path))
+		if err != nil {
+			if errors.Is(err, fs.ErrNotExist) {
+				if isFirstLevel {
+					serveIndexFile(writer, request)
+				} else {
+					notFoundHandler(writer, request)
+				}
+				return
+			}
+			writeErr(writer, err)
+			return
+		}
+		defer func() {
+			_ = file.Close()
+		}()
+
+		fileInfo, err := file.Stat()
+		if err != nil {
+			writeErr(writer, err)
+			return
+		}
+
+		if fileInfo.IsDir() {
+			if isFirstLevel {
+				serveIndexFile(writer, request)
+			} else {
+				notFoundHandler(writer, request)
+			}
+			return
+		}
+
+		content, err := io.ReadAll(file)
+		if err != nil {
+			writeErr(writer, err)
+			return
+		}
+
+		writer.Header().Set("Content-Type", mime.TypeByExtension(fileInfo.Name()))
+		writer.Header().Set("Content-Length", strconv.Itoa(len(content)))
+		_, _ = writer.Write(content)
+	}
+}
+
+func serveIndexFile(writer http.ResponseWriter, _ *http.Request) {
+	indexFile, err := frontend.ReadFile("frontend/index.html")
+	if err != nil {
+		writeErr(writer, err)
+		return
+	}
+	writer.Header().Set("Content-Type", "text/html")
+	writer.Header().Set("Content-Length", strconv.Itoa(len(indexFile)))
+	_, _ = writer.Write(indexFile)
+}

internal/web/server.go

@@ -39,7 +39,11 @@ type Server struct {
 func (server *Server) Start() error {
 	router := chi.NewRouter()
 
+	// Serve the web frontend
+	router.Get("/*", frontendHandler(router.NotFoundHandler()))
+
 	// Register the paste API endpoints
+	router.Get("/api/*", router.NotFoundHandler())
 	router.With(server.v2MiddlewareInjectPaste).Get("/api/v2/pastes/{paste_id}", server.v2EndpointGetPaste)
 	router.Post("/api/v2/pastes", server.v2EndpointCreatePaste)
 	router.With(server.v2MiddlewareInjectPaste, server.v2MiddlewareAuthorize).Patch("/api/v2/pastes/{paste_id}", server.v2EndpointModifyPaste)