fix: Code for category

api/openapi.yaml

@@ -160,10 +160,18 @@ paths:
         - name: category_id
           in: query
           required: false
-          description: Filter to a category.
+          description: Filter to a category by id.
           schema:
             type: string
             format: uuid
+        - name: category_code
+          in: query
+          required: false
+          description: >-
+            Filter to a category by its code (slug). An unknown code yields an
+            empty page.
+          schema:
+            type: string
       responses:
         "200":
           description: A page of dataset summaries
@@ -187,7 +195,7 @@ paths:
           multipart/form-data:
             schema:
               type: object
-              required: [file, file_type, category_id, code]
+              required: [file, file_type, category_id]
               properties:
                 file:
                   type: string
@@ -198,9 +206,6 @@ paths:
                 category_id:
                   type: string
                   format: uuid
-                code:
-                  type: string
-                  description: Business code.
                 name:
                   type: string
                   description: Display name; defaults to the filename if omitted.
@@ -441,7 +446,7 @@ components:
 
     Category:
       type: object
-      required: [id, name, description, created_at, updated_at]
+      required: [id, code, name, description, created_at, updated_at]
       properties:
         id:
           type: string
@@ -449,6 +454,9 @@ components:
         parent_id:
           type: [string, "null"]
           format: uuid
+        code:
+          type: string
+          description: Slug (lowercase latin letters, digits, and dashes).
         name:
           type: string
         description:
@@ -462,11 +470,16 @@ components:
 
     CategoryInput:
       type: object
-      required: [name]
+      required: [code, name]
       properties:
         parent_id:
           type: [string, "null"]
           format: uuid
+        code:
+          type: string
+          maxLength: 255
+          pattern: "^[a-z0-9]+(?:-[a-z0-9]+)*$"
+          description: Slug (lowercase latin letters, digits, and dashes).
         name:
           type: string
           maxLength: 255
@@ -505,7 +518,7 @@ components:
 
     DatasetSummary:
       type: object
-      required: [id, category_id, code, name, file_type, size_bytes, status, created_at, updated_at]
+      required: [id, category_id, name, file_type, size_bytes, status, created_at, updated_at]
       properties:
         id:
           type: string
@@ -513,8 +526,6 @@ components:
         category_id:
           type: string
           format: uuid
-        code:
-          type: string
         name:
           type: string
         description:
@@ -538,7 +549,7 @@ components:
     Dataset:
       type: object
       required:
-        [id, category_id, code, name, filename, storage_key, file_type,
+        [id, category_id, name, filename, storage_key, file_type,
          size_bytes, content_type, automated, status, created_at, updated_at]
       properties:
         id:
@@ -547,8 +558,6 @@ components:
         category_id:
           type: string
           format: uuid
-        code:
-          type: string
         name:
           type: string
         description:

internal/app/app.go

@@ -11,6 +11,7 @@ import (
 
 	"gis/api"
 	"gis/internal/config"
+	"gis/internal/domain"
 	"gis/internal/messaging/rabbitmq"
 	"gis/internal/parser"
 	"gis/internal/platform/logger"
@@ -87,6 +88,9 @@ func New(ctx context.Context) (*App, error) {
 // Handler builds the HTTP handler with all routes and readiness checks wired.
 func (a *App) Handler() stdhttp.Handler {
 	validate := validator.New(validator.WithRequiredStructEnabled())
+	validate.RegisterValidation("slug", func(fl validator.FieldLevel) bool {
+		return domain.ValidSlug(fl.Field().String())
+	})
 
 	health := transporthttp.NewHealthHandler(map[string]transporthttp.ReadinessCheck{
 		"postgres": func(ctx context.Context) error { return a.pool.Ping(ctx) },

internal/domain/category.go

@@ -1,6 +1,7 @@
 package domain
 
 import (
+	"regexp"
 	"time"
 
 	"github.com/google/uuid"
@@ -11,8 +12,19 @@ import (
 type Category struct {
 	ID          uuid.UUID  `json:"id"`
 	ParentID    *uuid.UUID `json:"parent_id"`
+	Code        string     `json:"code"`
 	Name        string     `json:"name"`
 	Description string     `json:"description"`
 	CreatedAt   time.Time  `json:"created_at"`
 	UpdatedAt   time.Time  `json:"updated_at"`
 }
+
+// slugPattern matches a slug: lowercase latin letters and digits in
+// dash-separated groups, e.g. "population", "land-use-2024".
+var slugPattern = regexp.MustCompile(`^[a-z0-9]+(?:-[a-z0-9]+)*$`)
+
+// ValidSlug reports whether s is a valid slug (lowercase latin letters, digits,
+// and single dashes between groups; no leading, trailing, or repeated dashes).
+func ValidSlug(s string) bool {
+	return slugPattern.MatchString(s)
+}

internal/domain/dataset.go

@@ -145,7 +145,6 @@ type YearColumn struct {
 type DatasetSummary struct {
 	ID          uuid.UUID `json:"id"`
 	CategoryID  uuid.UUID `json:"category_id"`
-	Code        string    `json:"code"`
 	Name        string    `json:"name"`
 	Description *string   `json:"description"`
 	Unit        *string   `json:"unit"`
@@ -160,7 +159,6 @@ type DatasetSummary struct {
 type Dataset struct {
 	ID          uuid.UUID `json:"id"`
 	CategoryID  uuid.UUID `json:"category_id"`
-	Code        string    `json:"code"`
 	Name        string    `json:"name"`
 	Description *string   `json:"description"`
 	Unit        *string   `json:"unit"`

internal/repository/postgres/category.go

@@ -20,21 +20,21 @@ func NewCategoryRepository(pool *pgxpool.Pool) *CategoryRepository {
 	return &CategoryRepository{pool: pool}
 }
 
-const categoryColumns = `id, parent_id, name, description, created_at, updated_at`
+const categoryColumns = `id, parent_id, code, name, description, created_at, updated_at`
 
 func scanCategory(row pgx.Row) (domain.Category, error) {
 	var c domain.Category
-	err := row.Scan(&c.ID, &c.ParentID, &c.Name, &c.Description, &c.CreatedAt, &c.UpdatedAt)
+	err := row.Scan(&c.ID, &c.ParentID, &c.Code, &c.Name, &c.Description, &c.CreatedAt, &c.UpdatedAt)
 	return c, err
 }
 
 // Create inserts a new category and returns the stored row.
 func (r *CategoryRepository) Create(ctx context.Context, c domain.Category) (domain.Category, error) {
 	row := r.pool.QueryRow(ctx,
-		`INSERT INTO categories (parent_id, name, description)
+		`INSERT INTO categories (parent_id, code, name, description)
-		 VALUES ($1, $2, $3)
+		 VALUES ($1, $2, $3, $4)
 		 RETURNING `+categoryColumns,
-		c.ParentID, c.Name, c.Description,
+		c.ParentID, c.Code, c.Name, c.Description,
 	)
 	out, err := scanCategory(row)
 	return out, mapError(err)
@@ -48,6 +48,14 @@ func (r *CategoryRepository) GetByID(ctx context.Context, id uuid.UUID) (domain.
 	return out, mapError(err)
 }
 
+// GetByCode returns the category with the given code, or domain.ErrNotFound.
+func (r *CategoryRepository) GetByCode(ctx context.Context, code string) (domain.Category, error) {
+	row := r.pool.QueryRow(ctx,
+		`SELECT `+categoryColumns+` FROM categories WHERE code = $1`, code)
+	out, err := scanCategory(row)
+	return out, mapError(err)
+}
+
 // List returns categories ordered by name. When parentID is non-nil it filters
 // to that parent's direct children; otherwise it returns all categories.
 func (r *CategoryRepository) List(ctx context.Context, parentID *uuid.UUID) ([]domain.Category, error) {
@@ -82,10 +90,10 @@ func (r *CategoryRepository) List(ctx context.Context, parentID *uuid.UUID) ([]d
 func (r *CategoryRepository) Update(ctx context.Context, c domain.Category) (domain.Category, error) {
 	row := r.pool.QueryRow(ctx,
 		`UPDATE categories
-		 SET parent_id = $2, name = $3, description = $4, updated_at = now()
+		 SET parent_id = $2, code = $3, name = $4, description = $5, updated_at = now()
 		 WHERE id = $1
 		 RETURNING `+categoryColumns,
-		c.ID, c.ParentID, c.Name, c.Description,
+		c.ID, c.ParentID, c.Code, c.Name, c.Description,
 	)
 	out, err := scanCategory(row)
 	return out, mapError(err)

internal/repository/postgres/dataset.go

@@ -26,7 +26,7 @@ func NewDatasetRepository(pool *pgxpool.Pool) *DatasetRepository {
 // datasetColumns lists the dataset columns for SELECT and RETURNING. The
 // geometry is exposed as GeoJSON (jsonb) rather than its raw EWKB form, and a
 // bounding box array is derived for raster datasets only.
-const datasetColumns = `id, category_id, code, name, description, unit, filename, storage_key, cog_storage_key, file_type, size_bytes, content_type, properties, meta, automated, status, attribute_columns, kato_column, year_columns, parse_error, ST_AsGeoJSON(geometry)::jsonb AS geometry,
+const datasetColumns = `id, category_id, name, description, unit, filename, storage_key, cog_storage_key, file_type, size_bytes, content_type, properties, meta, automated, status, attribute_columns, kato_column, year_columns, parse_error, ST_AsGeoJSON(geometry)::jsonb AS geometry,
 	CASE WHEN file_type = 'raster' AND geometry IS NOT NULL
 	     THEN ARRAY[ST_XMin(geometry), ST_YMin(geometry), ST_XMax(geometry), ST_YMax(geometry)]
 	     ELSE NULL END AS bbox,
@@ -35,7 +35,7 @@ const datasetColumns = `id, category_id, code, name, description, unit, filename
 func scanDataset(row pgx.Row) (domain.Dataset, error) {
 	var d domain.Dataset
 	err := row.Scan(
-		&d.ID, &d.CategoryID, &d.Code, &d.Name, &d.Description, &d.Unit,
+		&d.ID, &d.CategoryID, &d.Name, &d.Description, &d.Unit,
 		&d.Filename, &d.StorageKey, &d.CogStorageKey, &d.FileType, &d.SizeBytes, &d.ContentType,
 		&d.Properties, &d.Meta, &d.Automated, &d.Status,
 		&d.AttributeColumns, &d.KatoColumn, &d.YearColumns, &d.ParseError,
@@ -56,10 +56,10 @@ func nullableJSON(raw json.RawMessage) any {
 // Create inserts a new dataset and returns the stored row.
 func (r *DatasetRepository) Create(ctx context.Context, d domain.Dataset) (domain.Dataset, error) {
 	row := r.pool.QueryRow(ctx,
-		`INSERT INTO datasets (category_id, code, name, description, unit, filename, storage_key, file_type, size_bytes, content_type, properties, meta, automated, status)
+		`INSERT INTO datasets (category_id, name, description, unit, filename, storage_key, file_type, size_bytes, content_type, properties, meta, automated, status)
-		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13)
 		 RETURNING `+datasetColumns,
-		d.CategoryID, d.Code, d.Name, d.Description, d.Unit, d.Filename, d.StorageKey, d.FileType, d.SizeBytes, d.ContentType,
+		d.CategoryID, d.Name, d.Description, d.Unit, d.Filename, d.StorageKey, d.FileType, d.SizeBytes, d.ContentType,
 		nullableJSON(d.Properties), nullableJSON(d.Meta), d.Automated, d.Status,
 	)
 	out, err := scanDataset(row)
@@ -269,12 +269,12 @@ func (r *DatasetRepository) GetByID(ctx context.Context, id uuid.UUID) (domain.D
 	return out, mapError(err)
 }
 
-const datasetSummaryColumns = `id, category_id, code, name, description, unit, file_type, size_bytes, status, created_at, updated_at`
+const datasetSummaryColumns = `id, category_id, name, description, unit, file_type, size_bytes, status, created_at, updated_at`
 
 func scanDatasetSummary(row pgx.Row) (domain.DatasetSummary, error) {
 	var d domain.DatasetSummary
 	err := row.Scan(
-		&d.ID, &d.CategoryID, &d.Code, &d.Name, &d.Description, &d.Unit,
+		&d.ID, &d.CategoryID, &d.Name, &d.Description, &d.Unit,
 		&d.FileType, &d.SizeBytes, &d.Status, &d.CreatedAt, &d.UpdatedAt,
 	)
 	return d, err

internal/service/category.go

@@ -25,6 +25,7 @@ type CategoryRepository interface {
 // CategoryInput carries the mutable fields of a category.
 type CategoryInput struct {
 	ParentID    *uuid.UUID
+	Code        string
 	Name        string
 	Description string
 }
@@ -39,13 +40,17 @@ func NewCategoryService(repo CategoryRepository) *CategoryService {
 	return &CategoryService{repo: repo}
 }
 
-// Create validates the parent (if any) and stores a new category.
+// Create validates the code and parent (if any) and stores a new category.
 func (s *CategoryService) Create(ctx context.Context, in CategoryInput) (domain.Category, error) {
+	if !domain.ValidSlug(in.Code) {
+		return domain.Category{}, fmt.Errorf("%w: code must be a slug (lowercase latin letters, digits, and dashes)", domain.ErrValidation)
+	}
 	if err := s.ensureParentExists(ctx, in.ParentID); err != nil {
 		return domain.Category{}, err
 	}
 	return s.repo.Create(ctx, domain.Category{
 		ParentID:    in.ParentID,
+		Code:        in.Code,
 		Name:        in.Name,
 		Description: in.Description,
 	})
@@ -61,8 +66,11 @@ func (s *CategoryService) List(ctx context.Context, parentID *uuid.UUID) ([]doma
 	return s.repo.List(ctx, parentID)
 }
 
-// Update validates the parent change (existence + no cycles) and stores it.
+// Update validates the code and parent change (existence + no cycles) and stores it.
 func (s *CategoryService) Update(ctx context.Context, id uuid.UUID, in CategoryInput) (domain.Category, error) {
+	if !domain.ValidSlug(in.Code) {
+		return domain.Category{}, fmt.Errorf("%w: code must be a slug (lowercase latin letters, digits, and dashes)", domain.ErrValidation)
+	}
 	if _, err := s.repo.GetByID(ctx, id); err != nil {
 		return domain.Category{}, err
 	}
@@ -75,6 +83,7 @@ func (s *CategoryService) Update(ctx context.Context, id uuid.UUID, in CategoryI
 	return s.repo.Update(ctx, domain.Category{
 		ID:          id,
 		ParentID:    in.ParentID,
+		Code:        in.Code,
 		Name:        in.Name,
 		Description: in.Description,
 	})

internal/service/category_test.go

@@ -54,7 +54,7 @@ func TestCategoryService_Create(t *testing.T) {
 
 	t.Run("root category succeeds", func(t *testing.T) {
 		svc := NewCategoryService(newStubCategoryRepo())
-		got, err := svc.Create(ctx, CategoryInput{Name: "root"})
+		got, err := svc.Create(ctx, CategoryInput{Code: "root", Name: "root"})
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -63,10 +63,19 @@ func TestCategoryService_Create(t *testing.T) {
 		}
 	})
 
+	t.Run("invalid code is a validation error", func(t *testing.T) {
+		svc := NewCategoryService(newStubCategoryRepo())
+		for _, code := range []string{"", "Root", "with space", "-leading", "double--dash"} {
+			if _, err := svc.Create(ctx, CategoryInput{Code: code, Name: "x"}); !errors.Is(err, domain.ErrValidation) {
+				t.Fatalf("code %q: want ErrValidation, got %v", code, err)
+			}
+		}
+	})
+
 	t.Run("missing parent is a validation error", func(t *testing.T) {
 		svc := NewCategoryService(newStubCategoryRepo())
 		missing := uuid.New()
-		_, err := svc.Create(ctx, CategoryInput{Name: "child", ParentID: &missing})
+		_, err := svc.Create(ctx, CategoryInput{Code: "child", Name: "child", ParentID: &missing})
 		if !errors.Is(err, domain.ErrValidation) {
 			t.Fatalf("want ErrValidation, got %v", err)
 		}
@@ -75,9 +84,9 @@ func TestCategoryService_Create(t *testing.T) {
 	t.Run("existing parent succeeds", func(t *testing.T) {
 		repo := newStubCategoryRepo()
 		svc := NewCategoryService(repo)
-		root, _ := svc.Create(ctx, CategoryInput{Name: "root"})
+		root, _ := svc.Create(ctx, CategoryInput{Code: "root", Name: "root"})
 
-		child, err := svc.Create(ctx, CategoryInput{Name: "child", ParentID: &root.ID})
+		child, err := svc.Create(ctx, CategoryInput{Code: "child", Name: "child", ParentID: &root.ID})
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -92,26 +101,26 @@ func TestCategoryService_Update_PreventsCycles(t *testing.T) {
 	repo := newStubCategoryRepo()
 	svc := NewCategoryService(repo)
 
-	root, _ := svc.Create(ctx, CategoryInput{Name: "root"})
+	root, _ := svc.Create(ctx, CategoryInput{Code: "root", Name: "root"})
-	child, _ := svc.Create(ctx, CategoryInput{Name: "child", ParentID: &root.ID})
+	child, _ := svc.Create(ctx, CategoryInput{Code: "child", Name: "child", ParentID: &root.ID})
 
 	t.Run("category cannot be its own parent", func(t *testing.T) {
-		_, err := svc.Update(ctx, root.ID, CategoryInput{Name: "root", ParentID: &root.ID})
+		_, err := svc.Update(ctx, root.ID, CategoryInput{Code: "root", Name: "root", ParentID: &root.ID})
 		if !errors.Is(err, domain.ErrValidation) {
 			t.Fatalf("want ErrValidation, got %v", err)
 		}
 	})
 
 	t.Run("category cannot descend from its own child", func(t *testing.T) {
-		_, err := svc.Update(ctx, root.ID, CategoryInput{Name: "root", ParentID: &child.ID})
+		_, err := svc.Update(ctx, root.ID, CategoryInput{Code: "root", Name: "root", ParentID: &child.ID})
 		if !errors.Is(err, domain.ErrValidation) {
 			t.Fatalf("want ErrValidation, got %v", err)
 		}
 	})
 
 	t.Run("valid reparent succeeds", func(t *testing.T) {
-		other, _ := svc.Create(ctx, CategoryInput{Name: "other"})
+		other, _ := svc.Create(ctx, CategoryInput{Code: "other", Name: "other"})
-		updated, err := svc.Update(ctx, child.ID, CategoryInput{Name: "child", ParentID: &other.ID})
+		updated, err := svc.Update(ctx, child.ID, CategoryInput{Code: "child", Name: "child", ParentID: &other.ID})
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
@@ -123,7 +132,7 @@ func TestCategoryService_Update_PreventsCycles(t *testing.T) {
 
 func TestCategoryService_Update_MissingCategory(t *testing.T) {
 	svc := NewCategoryService(newStubCategoryRepo())
-	_, err := svc.Update(context.Background(), uuid.New(), CategoryInput{Name: "x"})
+	_, err := svc.Update(context.Background(), uuid.New(), CategoryInput{Code: "x", Name: "x"})
 	if !errors.Is(err, domain.ErrNotFound) {
 		t.Fatalf("want ErrNotFound, got %v", err)
 	}

internal/service/dataset.go

@@ -61,9 +61,11 @@ type ObjectStore interface {
 	Remove(ctx context.Context, key string) error
 }
 
-// categoryReader lets the dataset service verify a category exists before upload.
+// categoryReader lets the dataset service verify a category exists before upload
+// and resolve a category code to its id for list filtering.
 type categoryReader interface {
 	GetByID(ctx context.Context, id uuid.UUID) (domain.Category, error)
+	GetByCode(ctx context.Context, code string) (domain.Category, error)
 }
 
 // JobEnqueuer schedules asynchronous dataset jobs.
@@ -90,7 +92,6 @@ type RasterConverter interface {
 // UploadInput carries everything needed to store a new dataset.
 type UploadInput struct {
 	CategoryID  uuid.UUID
-	Code        string
 	Name        string
 	Description *string
 	Unit        *string
@@ -140,9 +141,6 @@ func NewDatasetService(
 // Upload validates input, stores the object, and persists the dataset. If the
 // database write fails after upload, the stored object is removed.
 func (s *DatasetService) Upload(ctx context.Context, in UploadInput) (domain.Dataset, error) {
-	if in.Code == "" {
-		return domain.Dataset{}, fmt.Errorf("%w: code is required", domain.ErrValidation)
-	}
 	if !in.FileType.Valid() {
 		return domain.Dataset{}, fmt.Errorf("%w: unknown file_type %q", domain.ErrValidation, in.FileType)
 	}
@@ -193,7 +191,6 @@ func (s *DatasetService) Upload(ctx context.Context, in UploadInput) (domain.Dat
 
 	dataset, err := s.repo.Create(ctx, domain.Dataset{
 		CategoryID:  in.CategoryID,
-		Code:        in.Code,
 		Name:        name,
 		Description: in.Description,
 		Unit:        in.Unit,
@@ -588,8 +585,10 @@ func (s *DatasetService) WaitForStatus(ctx context.Context, id uuid.UUID, curren
 }
 
 // ListSummaries returns a page of dataset summaries, optionally filtered to a
-// category. page is 1-based; page and pageSize are clamped to sane bounds.
+// category by id and/or by code. page is 1-based; page and pageSize are clamped
-func (s *DatasetService) ListSummaries(ctx context.Context, categoryID *uuid.UUID, page, pageSize int) (DatasetPage, error) {
+// to sane bounds. When categoryCode is set it is resolved to its category id; an
+// unknown code yields an empty page.
+func (s *DatasetService) ListSummaries(ctx context.Context, categoryID *uuid.UUID, categoryCode *string, page, pageSize int) (DatasetPage, error) {
 	if page < 1 {
 		page = 1
 	}
@@ -600,6 +599,17 @@ func (s *DatasetService) ListSummaries(ctx context.Context, categoryID *uuid.UUI
 		pageSize = MaxPageSize
 	}
 
+	if categoryCode != nil {
+		category, err := s.categories.GetByCode(ctx, *categoryCode)
+		if err != nil {
+			if errors.Is(err, domain.ErrNotFound) {
+				return DatasetPage{Items: []domain.DatasetSummary{}, Page: page, PageSize: pageSize}, nil
+			}
+			return DatasetPage{}, err
+		}
+		categoryID = &category.ID
+	}
+
 	items, err := s.repo.ListSummaries(ctx, categoryID, pageSize, (page-1)*pageSize)
 	if err != nil {
 		return DatasetPage{}, err

internal/service/dataset_test.go

@@ -254,11 +254,17 @@ func (s stubCategoryReader) GetByID(_ context.Context, id uuid.UUID) (domain.Cat
 	return domain.Category{ID: id}, nil
 }
 
+func (s stubCategoryReader) GetByCode(_ context.Context, code string) (domain.Category, error) {
+	if !s.exists {
+		return domain.Category{}, domain.ErrNotFound
+	}
+	return domain.Category{ID: uuid.New(), Code: code}, nil
+}
+
 func validUpload() UploadInput {
 	body := `{"type":"FeatureCollection","features":[]}`
 	return UploadInput{
 		CategoryID: uuid.New(),
-		Code:       "POP",
 		Name:       "Population",
 		Filename:   "data.geojson",
 		FileType:   domain.FileTypeVector,
@@ -278,7 +284,6 @@ func TestDatasetService_Upload_Validation(t *testing.T) {
 		name   string
 		mutate func(*UploadInput)
 	}{
-		{"missing code", func(in *UploadInput) { in.Code = "" }},
 		{"invalid file type", func(in *UploadInput) { in.FileType = "bogus" }},
 		{"unknown extension", func(in *UploadInput) { in.Filename = "data.txt" }},
 		{"extension/type mismatch", func(in *UploadInput) { in.Filename = "data.tif" }}, // .tif is raster
@@ -732,7 +737,7 @@ func TestDatasetService_ListSummaries_ClampsPaging(t *testing.T) {
 	svc := newDatasetService(repo, &stubStore{}, true)
 
 	// page < 1 -> 1, pageSize > max -> MaxPageSize, offset = 0.
-	res, err := svc.ListSummaries(context.Background(), nil, 0, 10_000)
+	res, err := svc.ListSummaries(context.Background(), nil, nil, 0, 10_000)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -747,7 +752,7 @@ func TestDatasetService_ListSummaries_ClampsPaging(t *testing.T) {
 	}
 
 	// page 3, pageSize 20 -> offset 40.
-	if _, err := svc.ListSummaries(context.Background(), nil, 3, 20); err != nil {
+	if _, err := svc.ListSummaries(context.Background(), nil, nil, 3, 20); err != nil {
 		t.Fatal(err)
 	}
 	if repo.lastOffset != 40 || repo.lastLimit != 20 {

internal/transport/http/category_handler.go

@@ -34,12 +34,13 @@ func (h *CategoryHandler) Register(r chi.Router) {
 
 type categoryRequest struct {
 	ParentID    *string `json:"parent_id" validate:"omitempty,uuid"`
+	Code        string  `json:"code" validate:"required,max=255,slug"`
 	Name        string  `json:"name" validate:"required,max=255"`
 	Description string  `json:"description" validate:"max=2000"`
 }
 
 func (r categoryRequest) toInput() (service.CategoryInput, error) {
-	in := service.CategoryInput{Name: r.Name, Description: r.Description}
+	in := service.CategoryInput{Code: r.Code, Name: r.Name, Description: r.Description}
 	if r.ParentID != nil {
 		id, err := uuid.Parse(*r.ParentID)
 		if err != nil {

internal/transport/http/dataset_handler.go

@@ -131,12 +131,6 @@ func (h *DatasetHandler) upload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	code := r.FormValue("code")
-	if code == "" {
-		httputil.WriteError(w, http.StatusUnprocessableEntity, "code is required")
-		return
-	}
-
 	meta, ok := optionalJSONFormValue(w, r, "meta")
 	if !ok {
 		return
@@ -162,7 +156,6 @@ func (h *DatasetHandler) upload(w http.ResponseWriter, r *http.Request) {
 
 	dataset, err := h.svc.Upload(r.Context(), service.UploadInput{
 		CategoryID:  categoryID,
-		Code:        code,
 		Name:        r.FormValue("name"),
 		Description: optionalFormValue(r, "description"),
 		Unit:        optionalFormValue(r, "unit"),
@@ -220,6 +213,10 @@ func (h *DatasetHandler) list(w http.ResponseWriter, r *http.Request) {
 	if !ok {
 		return
 	}
+	var categoryCode *string
+	if v := strings.TrimSpace(r.URL.Query().Get("category_code")); v != "" {
+		categoryCode = &v
+	}
 	page, ok := parsePositiveIntQuery(w, r, "page", 1)
 	if !ok {
 		return
@@ -229,7 +226,7 @@ func (h *DatasetHandler) list(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	res, err := h.svc.ListSummaries(r.Context(), categoryID, page, pageSize)
+	res, err := h.svc.ListSummaries(r.Context(), categoryID, categoryCode, page, pageSize)
 	if err != nil {
 		respondDomainError(w, err)
 		return

migrations/00002_create_categories_table.sql

@@ -2,6 +2,8 @@
 CREATE TABLE categories (
     id          UUID PRIMARY KEY      DEFAULT gen_random_uuid(),
     parent_id   UUID                  REFERENCES categories (id) ON DELETE RESTRICT,
+    -- Slug: lowercase latin letters, digits, and dashes. Unique.
+    code        VARCHAR(255) NOT NULL  UNIQUE,
     name        VARCHAR(255) NOT NULL,
     description TEXT         NOT NULL  DEFAULT '',
     created_at  TIMESTAMPTZ  NOT NULL  DEFAULT now(),

migrations/00003_create_datasets_table.sql

@@ -4,7 +4,6 @@ CREATE TYPE file_type AS ENUM ('vector_with_kato', 'vector', 'raster');
 CREATE TABLE datasets (
     id           UUID PRIMARY KEY       DEFAULT gen_random_uuid(),
     category_id  UUID         NOT NULL  REFERENCES categories (id) ON DELETE RESTRICT,
-    code         VARCHAR(255) NOT NULL,
     name         VARCHAR(255) NOT NULL,
     description  TEXT,
     unit         VARCHAR(255),