validator: ValidateMap: make sure that required fields exist

validator.go

@@ -809,10 +809,29 @@ func ValidateMap(s map[string]interface{}, m map[string]interface{}) (bool, erro
 		result = result && presentResult && typeResult && resultField && structResult && mapResult
 		index++
 	}
+	// check required keys
+	requiredResult := true
+	for key, value := range m {
+		if schema, ok := value.(string); ok {
+			tags := parseTagIntoMap(schema)
+			if required, ok := tags["required"]; ok {
+				if _, ok := s[key]; !ok {
+					requiredResult = false
+					if required.customErrorMessage != "" {
+						err = Error{key, fmt.Errorf(required.customErrorMessage), true, "required", []string{}}
+					} else {
+						err = Error{key, fmt.Errorf("required field missing"), false, "required", []string{}}
+					}
+					errs = append(errs, err)
+				}
+			}
+		}
+	}
+
 	if len(errs) > 0 {
 		err = errs
 	}
-	return result, err
+	return result && requiredResult, err
 }
 
 // ValidateStruct use tags for fields.

validator_test.go

@@ -3904,6 +3904,52 @@ func TestValidateMap(t *testing.T) {
 	}
 }
 
+func TestValidateMapMissing(t *testing.T) {
+	t.Parallel()
+	var tests = []struct {
+		params    map[string]interface{}
+		validator map[string]interface{}
+		expected  bool
+	}{
+		{
+			map[string]interface{}{
+				"name": "Bob",
+			},
+			map[string]interface{}{
+				"name":   "required,alpha",
+				"family": "required,alpha",
+			},
+			false,
+		},
+		{
+			map[string]interface{}{
+				"name": "Bob",
+				"submap": map[string]interface{}{
+					"family": "Smith",
+				},
+			},
+			map[string]interface{}{
+				"name": "required,alpha",
+				"submap": map[string]interface{}{
+					"name":   "required,alpha",
+					"family": "required,alpha",
+				},
+			},
+			false,
+		},
+	}
+
+	for _, test := range tests {
+		actual, err := ValidateMap(test.params, test.validator)
+		if actual != test.expected {
+			t.Errorf("Expected ValidateMap(%q, %q) to be %v, got %v", test.params, test.validator, test.expected, actual)
+			if err != nil {
+				t.Errorf("Got Error on ValidateMap(%q, %q): %s", test.params, test.validator, err)
+			}
+		}
+	}
+}
+
 func TestIsType(t *testing.T) {
 	t.Parallel()
 	i := 1