Feat: format API validation errors

internal/api/error.go

@@ -3,6 +3,8 @@ package api
 import (
 	"errors"
 	"fmt"
+	"reflect"
+	"strings"
 
 	"github.com/go-playground/validator/v10"
 
@@ -26,13 +28,36 @@ func NewError(err error) Error {
 	return e
 }
 
-func Validator(err error) Error {
+func Validator(err error, invalidObj any) Error {
 	e := Error{}
-	e.Errors = make(map[string]any)
+	e.Errors = make(map[string]interface{})
 	var errs validator.ValidationErrors
-	errors.As(err, &errs)
+
+	if !errors.As(err, &errs) {
+		return e
+	}
+
+	invalidObjType := reflect.TypeOf(invalidObj)
+
+	if invalidObjType.Kind() == reflect.Ptr {
+		invalidObjType = invalidObjType.Elem()
+	}
+
 	for _, v := range errs {
-		e.Errors[v.Field()] = fmt.Sprintf("%v", v.Tag())
+		fieldName := v.StructField()
+		jsonTag := fieldName
+		if f, ok := invalidObjType.FieldByName(fieldName); ok {
+			tag := f.Tag.Get("json")
+			if tag != "" && tag != "-" {
+				jsonTag = strings.Split(tag, ",")[0]
+			}
+		}
+		msg := fmt.Sprintf("validation failed on '%s'", v.Tag())
+		if errList, ok := e.Errors[jsonTag].([]string); ok {
+			e.Errors[jsonTag] = append(errList, msg)
+		} else {
+			e.Errors[jsonTag] = []string{msg}
+		}
 	}
 	return e
 }

internal/api/handler/evidence.go

@@ -179,7 +179,7 @@ func (h *EvidenceHandler) Create(ctx echo.Context) error {
 
 	err := ctx.Validate(input)
 	if err != nil {
-		return ctx.JSON(http.StatusBadRequest, api.Validator(err))
+		return ctx.JSON(http.StatusBadRequest, api.Validator(err, input))
 	}
 
 	components := []relational.SystemComponent{}

internal/api/handler/filter.go

@@ -2,6 +2,8 @@ package handler
 
 import (
 	"errors"
+	"net/http"
+
 	"github.com/compliance-framework/api/internal/api"
 	"github.com/compliance-framework/api/internal/service/relational"
 	oscalTypes_1_1_3 "github.com/defenseunicorns/go-oscal/src/types/oscal-1-1-3"
@@ -10,7 +12,6 @@ import (
 	"go.uber.org/zap"
 	"gorm.io/datatypes"
 	"gorm.io/gorm"
-	"net/http"
 )
 
 // FilterHandler handles CRUD operations for filters.
@@ -136,7 +137,7 @@ func (h *FilterHandler) Create(ctx echo.Context) error {
 		return ctx.JSON(http.StatusBadRequest, api.NewError(err))
 	}
 	if err := ctx.Validate(req); err != nil {
-		return ctx.JSON(http.StatusBadRequest, api.Validator(err))
+		return ctx.JSON(http.StatusBadRequest, api.Validator(err, req))
 	}
 
 	filter := relational.Filter{
@@ -190,7 +191,7 @@ func (h *FilterHandler) Update(ctx echo.Context) error {
 		return ctx.JSON(http.StatusBadRequest, api.NewError(err))
 	}
 	if err := ctx.Validate(req); err != nil {
-		return ctx.JSON(http.StatusBadRequest, api.Validator(err))
+		return ctx.JSON(http.StatusBadRequest, api.Validator(err, req))
 	}
 
 	var filter relational.Filter

internal/api/handler/heartbeat.go

@@ -1,14 +1,15 @@
 package handler
 
 import (
+	"net/http"
+	"time"
+
 	"github.com/compliance-framework/api/internal/api"
 	"github.com/compliance-framework/api/internal/service"
 	"github.com/google/uuid"
 	"github.com/labstack/echo/v4"
 	"go.uber.org/zap"
 	"gorm.io/gorm"
-	"net/http"
-	"time"
 )
 
 type HeartbeatHandler struct {
@@ -54,7 +55,7 @@ func (h *HeartbeatHandler) Create(ctx echo.Context) error {
 
 	err := ctx.Validate(heartbeat)
 	if err != nil {
-		return ctx.JSON(http.StatusBadRequest, api.Validator(err))
+		return ctx.JSON(http.StatusBadRequest, api.Validator(err, heartbeat))
 	}
 
 	if err := h.db.Create(&service.Heartbeat{
@@ -78,7 +79,6 @@ func (h *HeartbeatHandler) Create(ctx echo.Context) error {
 //	@Failure		500	{object}	api.Error
 //	@Router			/agent/heartbeat/over-time [get]
 func (h *HeartbeatHandler) OverTime(ctx echo.Context) error {
-
 	type HeartbeatInterval struct {
 		Interval time.Time `json:"interval"`
 		Total    int64     `json:"total"`

internal/api/handler/users.go

@@ -156,6 +156,11 @@ func (h *UserHandler) CreateUser(ctx echo.Context) error {
 		return ctx.JSON(400, api.NewError(err))
 	}
 
+	err := ctx.Validate(req)
+	if err != nil {
+		return ctx.JSON(400, api.Validator(err, req))
+	}
+
 	user := &relational.User{
 		Email:     req.Email,
 		FirstName: req.FirstName,

internal/api/handler/users_integration_test.go

@@ -161,6 +161,47 @@ func (suite *UserApiIntegrationSuite) TestCreateUser() {
 		suite.Equal(409, rec.Code, "Expected Conflict response for CreateUser with existing email")
 		suite.Contains(rec.Body.String(), "email already exists", "Expected error message for existing email in CreateUser response")
 	})
+
+	suite.Run("CreateUserWithInvalidEmail", func() {
+		existingUser := createUserRequest{
+			Email:     "invalid",
+			Password:  "password123",
+			FirstName: "Existing",
+			LastName:  "User",
+		}
+
+		existingUserJSON, err := json.Marshal(existingUser)
+		suite.Require().NoError(err, "Failed to marshal existing user request")
+
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest("POST", "/api/users", bytes.NewReader(existingUserJSON))
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("Authorization", "Bearer "+*token)
+
+		suite.server.E().ServeHTTP(rec, req)
+		suite.Equal(400, rec.Code, "Expected error response for CreateUser with invalid email")
+		suite.Contains(rec.Body.String(), "{\"errors\":{\"email\":[\"validation failed on 'email'\"]}}\n", "Expected error message for invalid email in CreateUser response")
+	})
+	suite.Run("CreateUserWithMissingEmail", func() {
+		existingUser := createUserRequest{
+			Email:     "",
+			Password:  "password123",
+			FirstName: "Existing",
+			LastName:  "User",
+		}
+
+		existingUserJSON, err := json.Marshal(existingUser)
+		suite.Require().NoError(err, "Failed to marshal existing user request")
+
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest("POST", "/api/users", bytes.NewReader(existingUserJSON))
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("Authorization", "Bearer "+*token)
+
+		suite.server.E().ServeHTTP(rec, req)
+		suite.Equal(400, rec.Code, "Expected error response for CreateUser with invalid email")
+		suite.Contains(rec.Body.String(), "{\"errors\":{\"email\":[\"validation failed on 'required'\"]}}\n", "Expected error message for invalid email in CreateUser response")
+	})
 }
 
 func (suite *UserApiIntegrationSuite) ModifyUser() {