feat(api): serve the category content field on GET /_journal/api/v1/categories

- add the nullable TEXT column golem15_journal_categories.content (migration 202610090001)
- map it as models.Category.Content and emit category content on every categories row
- document the categories row shape and the stored-as-is HTML semantics

updates/202610090001_add_content_to_golem15_journal_categories.go

@@ -0,0 +1,24 @@
+package updates
+
+import (
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+// addCategoryContent adds the category HTML body (D-21). It must stay the last
+// migration so RollbackLast drops only this column and keeps the rows.
+var addCategoryContent = []*gormigrate.Migration{
+	{
+		ID: "202610090001_add_content_to_golem15_journal_categories",
+		Migrate: func(tx *gorm.DB) error {
+			return tx.Exec(`ALTER TABLE golem15_journal_categories ADD COLUMN IF NOT EXISTS content TEXT NULL`).Error
+		},
+		Rollback: func(tx *gorm.DB) error {
+			return tx.Exec(`ALTER TABLE golem15_journal_categories DROP COLUMN IF EXISTS content`).Error
+		},
+	},
+}
+
+func init() {
+	Register(addCategoryContent...)
+}

updates/category_content_migration_test.go

@@ -0,0 +1,82 @@
+package updates
+
+import (
+	"database/sql"
+	"fmt"
+	"testing"
+	"time"
+
+	"git.golem15.com/golem15/summercms/modules/lagoon"
+	"github.com/go-gormigrate/gormigrate/v2"
+)
+
+func TestCategoryContentMigration(t *testing.T) {
+	sqlDB := dedicatedDB(t, fmt.Sprintf("journal_catcontent_%d", time.Now().UnixNano()))
+	gdb, err := lagoon.Use(t.Context(), sqlDB)
+	if err != nil {
+		t.Fatal(err)
+	}
+	backend := gormigrate.New(gdb, &gormigrate.Options{
+		TableName:      "summer_migrations_summercms_cabana",
+		UseTransaction: true,
+	}, lagoon.BackendAdminMigrations)
+	if err := backend.Migrate(); err != nil {
+		t.Fatalf("backend_users migrations: %v", err)
+	}
+	m := journalMigrator(gdb)
+	if err := m.Migrate(); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	all := All()
+	if last := all[len(all)-1].ID; last != "202610090001_add_content_to_golem15_journal_categories" {
+		t.Fatalf("last migration = %s, want 202610090001_add_content_to_golem15_journal_categories", last)
+	}
+	if !gdb.Migrator().HasColumn("golem15_journal_categories", "content") {
+		t.Fatal("golem15_journal_categories.content missing")
+	}
+	assertUdt(t, gdb, "golem15_journal_categories", "content", "text")
+	var nullable string
+	if err := gdb.WithContext(t.Context()).Raw(
+		`SELECT is_nullable FROM information_schema.columns WHERE table_name = 'golem15_journal_categories' AND column_name = 'content'`,
+	).Scan(&nullable).Error; err != nil {
+		t.Fatal(err)
+	}
+	if nullable != "YES" {
+		t.Fatalf("content is_nullable = %q, want YES", nullable)
+	}
+
+	if err := gdb.Exec(`UPDATE golem15_journal_categories SET content = '<p>x</p>' WHERE slug = 'uncategorized'`).Error; err != nil {
+		t.Fatal(err)
+	}
+	if err := m.RollbackLast(); err != nil {
+		t.Fatalf("rollback last: %v", err)
+	}
+	if !gdb.Migrator().HasTable("golem15_journal_categories") {
+		t.Fatal("golem15_journal_categories dropped by the content rollback")
+	}
+	if gdb.Migrator().HasColumn("golem15_journal_categories", "content") {
+		t.Fatal("content column survived rollback")
+	}
+	var rows int64
+	if err := gdb.Raw(`SELECT COUNT(*) FROM golem15_journal_categories WHERE slug = 'uncategorized'`).Scan(&rows).Error; err != nil {
+		t.Fatal(err)
+	}
+	if rows != 1 {
+		t.Fatalf("uncategorized rows after rollback = %d, want 1", rows)
+	}
+
+	if err := m.Migrate(); err != nil {
+		t.Fatalf("re-migrate: %v", err)
+	}
+	if !gdb.Migrator().HasColumn("golem15_journal_categories", "content") {
+		t.Fatal("content column missing after re-migrate")
+	}
+	var content sql.NullString
+	if err := gdb.Raw(`SELECT content FROM golem15_journal_categories WHERE slug = 'uncategorized'`).Scan(&content).Error; err != nil {
+		t.Fatal(err)
+	}
+	if content.Valid {
+		t.Fatalf("uncategorized content after re-migrate = %q, want NULL", content.String)
+	}
+}