Fix API returning null with 200 code when no records found

- Modified handleRead to always return empty array [] instead of null when no ID provided
- Added X-No-Data-Found header when result count is 0
- Updated normalizeResultArray to keep empty arrays as arrays instead of converting to empty objects
- Updated sendFormattedResponse and sendResponseWithOptions to handle empty data properly
- All responses now return 200 OK instead of 206 Partial Content when no data found
- Added comprehensive tests to verify the fix

Co-authored-by: warkanum <208308+warkanum@users.noreply.github.com>

pkg/restheadspec/empty_result_test.go

@@ -0,0 +1,196 @@
+package restheadspec
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
+)
+
+// Test that normalizeResultArray returns empty array when no records found without ID
+func TestNormalizeResultArray_EmptyArrayWhenNoID(t *testing.T) {
+	handler := &Handler{}
+
+	tests := []struct {
+		name     string
+		input    interface{}
+		expected interface{}
+	}{
+		{
+			name:     "nil should return empty array",
+			input:    nil,
+			expected: []interface{}{},
+		},
+		{
+			name:     "empty slice should return empty array",
+			input:    []*EmptyTestModel{},
+			expected: []interface{}{},
+		},
+		{
+			name:     "single element should return the element",
+			input:    []*EmptyTestModel{{ID: 1, Name: "test"}},
+			expected: &EmptyTestModel{ID: 1, Name: "test"},
+		},
+		{
+			name: "multiple elements should return the slice",
+			input: []*EmptyTestModel{
+				{ID: 1, Name: "test1"},
+				{ID: 2, Name: "test2"},
+			},
+			expected: []*EmptyTestModel{
+				{ID: 1, Name: "test1"},
+				{ID: 2, Name: "test2"},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := handler.normalizeResultArray(tt.input)
+
+			// For nil and empty cases, check it returns an empty array
+			if tt.input == nil || (tt.name == "empty slice should return empty array") {
+				emptyArr, ok := result.([]interface{})
+				if !ok {
+					t.Errorf("Expected empty array []interface{}{}, got %T: %v", result, result)
+					return
+				}
+				if len(emptyArr) != 0 {
+					t.Errorf("Expected empty array with length 0, got length %d", len(emptyArr))
+				}
+				
+				// Verify it serializes to [] and not null
+				jsonBytes, err := json.Marshal(result)
+				if err != nil {
+					t.Errorf("Failed to marshal result: %v", err)
+					return
+				}
+				if string(jsonBytes) != "[]" {
+					t.Errorf("Expected JSON '[]', got '%s'", string(jsonBytes))
+				}
+			}
+		})
+	}
+}
+
+// Test that sendFormattedResponse adds X-No-Data-Found header
+func TestSendFormattedResponse_NoDataFoundHeader(t *testing.T) {
+	handler := &Handler{}
+
+	// Mock ResponseWriter
+	mockWriter := &MockTestResponseWriter{
+		headers: make(map[string]string),
+	}
+
+	metadata := &common.Metadata{
+		Total:    0,
+		Count:    0,
+		Filtered: 0,
+		Limit:    10,
+		Offset:   0,
+	}
+
+	options := ExtendedRequestOptions{
+		RequestOptions: common.RequestOptions{},
+	}
+
+	// Test with empty data
+	emptyData := []interface{}{}
+	handler.sendFormattedResponse(mockWriter, emptyData, metadata, options)
+
+	// Check if X-No-Data-Found header was set
+	if mockWriter.headers["X-No-Data-Found"] != "true" {
+		t.Errorf("Expected X-No-Data-Found header to be 'true', got '%s'", mockWriter.headers["X-No-Data-Found"])
+	}
+
+	// Verify the body is an empty array
+	if mockWriter.body == nil {
+		t.Error("Expected body to be set, got nil")
+	} else {
+		bodyBytes, err := json.Marshal(mockWriter.body)
+		if err != nil {
+			t.Errorf("Failed to marshal body: %v", err)
+		}
+		// The body should be wrapped in a Response object with "data" field
+		bodyStr := string(bodyBytes)
+		if !strings.Contains(bodyStr, `"data":[]`) && !strings.Contains(bodyStr, `"result":[]`) {
+			t.Errorf("Expected body to contain empty array, got: %s", bodyStr)
+		}
+	}
+}
+
+// Test that sendResponseWithOptions adds X-No-Data-Found header
+func TestSendResponseWithOptions_NoDataFoundHeader(t *testing.T) {
+	handler := &Handler{}
+
+	// Mock ResponseWriter
+	mockWriter := &MockTestResponseWriter{
+		headers: make(map[string]string),
+	}
+
+	metadata := &common.Metadata{}
+	options := &ExtendedRequestOptions{}
+
+	// Test with nil data
+	handler.sendResponseWithOptions(mockWriter, nil, metadata, options)
+
+	// Check if X-No-Data-Found header was set
+	if mockWriter.headers["X-No-Data-Found"] != "true" {
+		t.Errorf("Expected X-No-Data-Found header to be 'true', got '%s'", mockWriter.headers["X-No-Data-Found"])
+	}
+
+	// Check status code is 200
+	if mockWriter.statusCode != 200 {
+		t.Errorf("Expected status code 200, got %d", mockWriter.statusCode)
+	}
+
+	// Verify the body is an empty array
+	if mockWriter.body == nil {
+		t.Error("Expected body to be set, got nil")
+	} else {
+		bodyBytes, err := json.Marshal(mockWriter.body)
+		if err != nil {
+			t.Errorf("Failed to marshal body: %v", err)
+		}
+		bodyStr := string(bodyBytes)
+		if bodyStr != "[]" {
+			t.Errorf("Expected body to be '[]', got: %s", bodyStr)
+		}
+	}
+}
+
+// MockTestResponseWriter for testing
+type MockTestResponseWriter struct {
+	headers    map[string]string
+	statusCode int
+	body       interface{}
+}
+
+func (m *MockTestResponseWriter) SetHeader(key, value string) {
+	m.headers[key] = value
+}
+
+func (m *MockTestResponseWriter) WriteHeader(statusCode int) {
+	m.statusCode = statusCode
+}
+
+func (m *MockTestResponseWriter) Write(data []byte) (int, error) {
+	return len(data), nil
+}
+
+func (m *MockTestResponseWriter) WriteJSON(data interface{}) error {
+	m.body = data
+	return nil
+}
+
+func (m *MockTestResponseWriter) UnderlyingResponseWriter() http.ResponseWriter {
+	return nil
+}
+
+// EmptyTestModel for testing
+type EmptyTestModel struct {
+	ID   int64  `json:"id"`
+	Name string `json:"name"`
+}

pkg/restheadspec/handler.go

@@ -2143,12 +2143,23 @@ func (h *Handler) sendResponse(w common.ResponseWriter, data interface{}, metada
 // sendResponseWithOptions sends a response with optional formatting
 func (h *Handler) sendResponseWithOptions(w common.ResponseWriter, data interface{}, metadata *common.Metadata, options *ExtendedRequestOptions) {
 	w.SetHeader("Content-Type", "application/json")
+	
+	// Calculate data length
+	dataLen := 0
 	if data == nil {
-		data = map[string]interface{}{}
-		w.WriteHeader(http.StatusPartialContent)
+		// When data is nil, return empty array instead of null
+		data = []interface{}{}
 	} else {
-		w.WriteHeader(http.StatusOK)
+		dataLen = reflection.Len(data)
 	}
+	
+	// Add X-No-Data-Found header when no records were found
+	if dataLen == 0 {
+		w.SetHeader("X-No-Data-Found", "true")
+	}
+	
+	w.WriteHeader(http.StatusOK)
+	
 	// Normalize single-record arrays to objects if requested
 	if options != nil && options.SingleRecordAsObject {
 		data = h.normalizeResultArray(data)
@@ -2165,7 +2176,7 @@ func (h *Handler) sendResponseWithOptions(w common.ResponseWriter, data interfac
 // Returns the single element if data is a slice/array with exactly one element, otherwise returns data unchanged
 func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 	if data == nil {
-		return map[string]interface{}{}
+		return []interface{}{}
 	}
 
 	// Use reflection to check if data is a slice or array
@@ -2180,15 +2191,15 @@ func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 			// Return the single element
 			return dataValue.Index(0).Interface()
 		} else if dataValue.Len() == 0 {
-			// Return empty object instead of empty array
-			return map[string]interface{}{}
+			// Keep empty array as empty array, don't convert to empty object
+			return []interface{}{}
 		}
 	}
 
 	if dataValue.Kind() == reflect.String {
 		str := dataValue.String()
 		if str == "" || str == "null" {
-			return map[string]interface{}{}
+			return []interface{}{}
 		}
 
 	}
@@ -2199,14 +2210,17 @@ func (h *Handler) normalizeResultArray(data interface{}) interface{} {
 func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata, options ExtendedRequestOptions) {
 	// Normalize single-record arrays to objects if requested
 	httpStatus := http.StatusOK
+	dataLen := 0
 	if data == nil {
-		data = map[string]interface{}{}
-		httpStatus = http.StatusPartialContent
+		// When data is nil, return empty array instead of null
+		data = []interface{}{}
 	} else {
-		dataLen := reflection.Len(data)
-		if dataLen == 0 {
-			httpStatus = http.StatusPartialContent
-		}
+		dataLen = reflection.Len(data)
+	}
+
+	// Add X-No-Data-Found header when no records were found
+	if dataLen == 0 {
+		w.SetHeader("X-No-Data-Found", "true")
 	}
 
 	if options.SingleRecordAsObject {