Db service fixes and improvements: dot access, truncate table etc (#157)

db/handler/db.go

@@ -22,6 +22,7 @@ import (
 
 const idKey = "id"
 const stmt = "create table if not exists %v(id text not null, data jsonb, primary key(id)); alter table %v add created_at timestamptz; alter table %v add updated_at timestamptz"
+const truncateStmt = `truncate table "%v"`
 
 var re = regexp.MustCompile("^[a-zA-Z0-9_]*$")
 var c = cache.New(5*time.Minute, 10*time.Minute)
@@ -39,6 +40,23 @@ type Db struct {
 	gorm2.Helper
 }
 
+func correctFieldName(s string) string {
+	switch s {
+	// top level fields can stay top level
+	case "id": // "created_at", "updated_at",  <-- these are not special fields for now
+		return s
+	}
+	if !strings.Contains(s, ".") {
+		return fmt.Sprintf("data ->> '%v'", s)
+	}
+	paths := strings.Split(s, ".")
+	ret := "data"
+	for _, path := range paths {
+		ret += fmt.Sprintf(" ->> '%v'", path)
+	}
+	return ret
+}
+
 // Call is a single request handler called via client.Call or the generated client code
 func (e *Db) Create(ctx context.Context, req *db.CreateRequest, rsp *db.CreateResponse) error {
 	if len(req.Record.AsMap()) == 0 {
@@ -208,13 +226,28 @@ func (e *Db) Read(ctx context.Context, req *db.ReadRequest, rsp *db.ReadResponse
 		case itemNotEquals:
 			op = "!="
 		}
-		db = db.Where(fmt.Sprintf("(data ->> '%v')::%v %v ?", query.Field, typ, op), query.Value)
+		queryField := correctFieldName(query.Field)
+		db = db.Where(fmt.Sprintf("(%v)::%v %v ?", queryField, typ, op), query.Value)
 	}
-	orderField := "created_at DESC"
+	orderField := "created_at"
 	if req.OrderBy != "" {
-		orderField = req.OrderBy + " " + req.Order
+		orderField = req.OrderBy
 	}
-	db = db.Order(orderField).Offset(int(req.Offset)).Limit(int(req.Limit))
+	orderField = correctFieldName(orderField)
+
+	ordering := "asc"
+	if req.Order != "" {
+		switch strings.ToLower(req.Order) {
+		case "asc":
+			ordering = "asc"
+		case "", "desc":
+			ordering = "desc"
+		default:
+			return errors.BadRequest("db.read", "invalid ordering: "+req.Order)
+		}
+	}
+
+	db = db.Order(orderField + " " + ordering).Offset(int(req.Offset)).Limit(int(req.Limit))
 	err = db.Find(&recs).Error
 	if err != nil {
 		return err
@@ -269,3 +302,25 @@ func (e *Db) Delete(ctx context.Context, req *db.DeleteRequest, rsp *db.DeleteRe
 		ID: req.Id,
 	}).Error
 }
+
+func (e *Db) Truncate(ctx context.Context, req *db.TruncateRequest, rsp *db.TruncateResponse) error {
+	tenantId, ok := tenant.FromContext(ctx)
+	if !ok {
+		tenantId = "micro"
+	}
+	if req.Table == "" {
+		req.Table = "default"
+	}
+	tenantId = strings.Replace(strings.Replace(tenantId, "/", "_", -1), "-", "_", -1)
+	tableName := tenantId + "_" + req.Table
+	if !re.Match([]byte(tableName)) {
+		return errors.BadRequest("db.create", fmt.Sprintf("table name %v is invalid", req.Table))
+	}
+	logger.Infof("Truncating table '%v'", tableName)
+
+	db, err := e.GetDBConn(ctx)
+	if err != nil {
+		return err
+	}
+	return db.Exec(fmt.Sprintf(truncateStmt, tableName)).Error
+}

db/handler/parse.go

@@ -57,7 +57,7 @@ var expressions = []lexer.TokenExpr{
 	{`"(?:[^"\\]|\\.)*"`, itemString},
 	{"`" + `(?:[^"\\]|\\.)*` + "`", itemString},
 	{`'(?:[^"\\]|\\.)*'`, itemString},
-	{`[\<\>\!\=\+\-\|\&\*\/A-Za-z][A-Za-z0-9_]*`, itemFieldName},
+	{`[\<\>\!\=\+\-\|\&\*\/A-Za-z][A-Za-z0-9_\.]*`, itemFieldName},
 }
 
 type Query struct {

db/handler/parse_test.go

@@ -8,6 +8,13 @@ import (
 	"github.com/crufter/lexer"
 )
 
+func TestCorrectFieldName(t *testing.T) {
+	f := correctFieldName("a.b.c")
+	if f != "data ->> 'a' ->> 'b' ->> 'c'" {
+		t.Fatal(f)
+	}
+}
+
 func TestLexing(t *testing.T) {
 	tokens, err := lexer.Lex("a == 12", expressions)
 	if err != nil {
@@ -55,6 +62,21 @@ func TestParsing(t *testing.T) {
 				},
 			},
 		},
+		tCase{
+			Q: `a.b.c == 12 and name != "nandos"`,
+			E: []Query{
+				Query{
+					Field: "a.b.c",
+					Value: int64(12),
+					Op:    itemEquals,
+				},
+				Query{
+					Field: "name",
+					Value: "nandos",
+					Op:    itemNotEquals,
+				},
+			},
+		},
 		tCase{
 			Q: `a == 12 and name != "nan'dos"`,
 			E: []Query{