Better relation lookup

pkg/restheadspec/headers.go

@@ -99,7 +99,8 @@ func DecodeParam(pStr string) (string, error) {
 }
 
 // parseOptionsFromHeaders parses all request options from HTTP headers
-func (h *Handler) parseOptionsFromHeaders(r common.Request) ExtendedRequestOptions {
+// If model is provided, it will resolve table names to field names in preload/expand options
+func (h *Handler) parseOptionsFromHeaders(r common.Request, model interface{}) ExtendedRequestOptions {
 	options := ExtendedRequestOptions{
 		RequestOptions: common.RequestOptions{
 			Filters: make([]common.FilterOption, 0),
@@ -225,6 +226,11 @@ func (h *Handler) parseOptionsFromHeaders(r common.Request) ExtendedRequestOptio
 		}
 	}
 
+	// Resolve relation names (convert table names to field names) if model is provided
+	if model != nil {
+		h.resolveRelationNamesInOptions(&options, model)
+	}
+
 	return options
 }
 
@@ -655,6 +661,169 @@ func (h *Handler) processXFilesRelations(xfiles *XFiles, options *ExtendedReques
 	}
 }
 
+// resolveRelationNamesInOptions resolves all table names to field names in preload options
+// This is called internally by parseOptionsFromHeaders when a model is provided
+func (h *Handler) resolveRelationNamesInOptions(options *ExtendedRequestOptions, model interface{}) {
+	if options == nil || model == nil {
+		return
+	}
+
+	// Resolve relation names in all preload options
+	for i := range options.Preload {
+		preload := &options.Preload[i]
+
+		// Split the relation path (e.g., "parent.child.grandchild")
+		parts := strings.Split(preload.Relation, ".")
+		resolvedParts := make([]string, 0, len(parts))
+
+		// Resolve each part of the path
+		currentModel := model
+		for _, part := range parts {
+			resolvedPart := h.resolveRelationName(currentModel, part)
+			resolvedParts = append(resolvedParts, resolvedPart)
+
+			// Try to get the model type for the next level
+			// This allows nested resolution
+			if nextModel := h.getRelationModel(currentModel, resolvedPart); nextModel != nil {
+				currentModel = nextModel
+			}
+		}
+
+		// Update the relation path with resolved names
+		resolvedPath := strings.Join(resolvedParts, ".")
+		if resolvedPath != preload.Relation {
+			logger.Debug("Resolved relation path '%s' -> '%s'", preload.Relation, resolvedPath)
+			preload.Relation = resolvedPath
+		}
+	}
+
+	// Resolve relation names in expand options
+	for i := range options.Expand {
+		expand := &options.Expand[i]
+		resolved := h.resolveRelationName(model, expand.Relation)
+		if resolved != expand.Relation {
+			logger.Debug("Resolved expand relation '%s' -> '%s'", expand.Relation, resolved)
+			expand.Relation = resolved
+		}
+	}
+}
+
+// getRelationModel gets the model type for a relation field
+func (h *Handler) getRelationModel(model interface{}, fieldName string) interface{} {
+	if model == nil || fieldName == "" {
+		return nil
+	}
+
+	modelType := reflect.TypeOf(model)
+	if modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	if modelType.Kind() != reflect.Struct {
+		return nil
+	}
+
+	// Find the field
+	field, found := modelType.FieldByName(fieldName)
+	if !found {
+		return nil
+	}
+
+	// Get the target type
+	targetType := field.Type
+	if targetType.Kind() == reflect.Slice {
+		targetType = targetType.Elem()
+	}
+	if targetType.Kind() == reflect.Ptr {
+		targetType = targetType.Elem()
+	}
+
+	if targetType.Kind() != reflect.Struct {
+		return nil
+	}
+
+	// Create a zero value of the target type
+	return reflect.New(targetType).Elem().Interface()
+}
+
+// resolveRelationName resolves a relation name or table name to the actual field name in the model
+// If the input is already a field name, it returns it as-is
+// If the input is a table name, it looks up the corresponding relation field
+func (h *Handler) resolveRelationName(model interface{}, nameOrTable string) string {
+	if model == nil || nameOrTable == "" {
+		return nameOrTable
+	}
+
+	modelType := reflect.TypeOf(model)
+	// Dereference pointer if needed
+	if modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	// Ensure it's a struct
+	if modelType.Kind() != reflect.Struct {
+		return nameOrTable
+	}
+
+	// First, check if the input matches a field name directly
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+		if field.Name == nameOrTable {
+			// It's already a field name
+			logger.Debug("Input '%s' is a field name", nameOrTable)
+			return nameOrTable
+		}
+	}
+
+	// If not found as a field name, try to look it up as a table name
+	normalizedInput := strings.ToLower(strings.ReplaceAll(nameOrTable, "_", ""))
+
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+		fieldType := field.Type
+
+		// Check if it's a slice or pointer to a struct
+		var targetType reflect.Type
+		if fieldType.Kind() == reflect.Slice {
+			targetType = fieldType.Elem()
+		} else if fieldType.Kind() == reflect.Ptr {
+			targetType = fieldType.Elem()
+		}
+
+		if targetType != nil {
+			// Dereference pointer if the slice contains pointers
+			if targetType.Kind() == reflect.Ptr {
+				targetType = targetType.Elem()
+			}
+
+			// Check if it's a struct type
+			if targetType.Kind() == reflect.Struct {
+				// Get the type name and normalize it
+				typeName := targetType.Name()
+
+				// Extract the table name from type name
+				// Patterns: ModelCoreMastertaskitem -> mastertaskitem
+				//           ModelMastertaskitem -> mastertaskitem
+				normalizedTypeName := strings.ToLower(typeName)
+
+				// Remove common prefixes like "model", "modelcore", etc.
+				normalizedTypeName = strings.TrimPrefix(normalizedTypeName, "modelcore")
+				normalizedTypeName = strings.TrimPrefix(normalizedTypeName, "model")
+
+				// Compare normalized names
+				if normalizedTypeName == normalizedInput {
+					logger.Debug("Resolved table name '%s' to field '%s' (type: %s)", nameOrTable, field.Name, typeName)
+					return field.Name
+				}
+			}
+		}
+	}
+
+	// If no match found, return the original input
+	logger.Debug("No field found for '%s', using as-is", nameOrTable)
+	return nameOrTable
+}
+
 // addXFilesPreload converts an XFiles relation into a PreloadOption
 // and recursively processes its children
 func (h *Handler) addXFilesPreload(xfile *XFiles, options *ExtendedRequestOptions, basePath string) {
@@ -662,7 +831,8 @@ func (h *Handler) addXFilesPreload(xfile *XFiles, options *ExtendedRequestOption
 		return
 	}
 
-	// Determine the relation path
+	// Store the table name as-is for now - it will be resolved to field name later
+	// when we have the model instance available
 	relationPath := xfile.TableName
 	if basePath != "" {
 		relationPath = basePath + "." + xfile.TableName