feat: scaffold files service

internal/handler/helpers.go

@@ -0,0 +1,44 @@
+package handler
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"strings"
+)
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+func writeError(w http.ResponseWriter, status int, msg string) {
+	writeJSON(w, status, map[string]string{"error": msg})
+}
+
+func writeInternalError(w http.ResponseWriter, r *http.Request, err error, msg string) {
+	slog.Error("http error", "method", r.Method, "path", r.URL.Path, "err", err)
+	writeError(w, http.StatusInternalServerError, msg)
+}
+
+func decodeJSON(r *http.Request, v any) error {
+	defer r.Body.Close()
+	return json.NewDecoder(r.Body).Decode(v)
+}
+
+func csvHeader(r *http.Request, key string) []string {
+	raw := r.Header.Get(key)
+	if raw == "" {
+		return nil
+	}
+	parts := strings.Split(raw, ",")
+	out := make([]string, 0, len(parts))
+	for _, p := range parts {
+		p = strings.TrimSpace(p)
+		if p != "" {
+			out = append(out, p)
+		}
+	}
+	return out
+}