added utf8 fix (#77)

* added utf8 fix?

* interface should be pointer to string

* fix comments

* check for UTF8 when decoding or encoding

* remove wrapping

* added tests

* update changelog, prep for release

CHANGELOG.md

@@ -5,7 +5,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
+## [v3.1.3]
 - Fix `500 Invalid WRP content type` for invalid `Accept` headers [#74](https://github.com/xmidt-org/wrp-go/pull/74)
+- Added helper function that errors if a wrp message contains non-UTF-8 strings. [#77](https://github.com/xmidt-org/wrp-go/pull/77)
 
 ## [v3.1.2]
 - Move ParseID func and relevant consts from webpa-common to wrp-go. [#75](https://github.com/xmidt-org/wrp-go/pull/75)
@@ -70,7 +73,8 @@ All changes included in [#47](https://github.com/xmidt-org/wrp-go/pull/47)
 ## [1.0.0]
 - This release is exactly the same as the last version from github.com/xmidt-org/webpa-common/wrp
 
-[Unreleased]: https://github.com/xmidt-org/wrp-go/compare/v3.1.2...HEAD
+[Unreleased]: https://github.com/xmidt-org/wrp-go/compare/v3.1.3...HEAD
+[v3.1.3]: https://github.com/xmidt-org/wrp-go/compare/v3.1.2...v3.1.3
 [v3.1.2]: https://github.com/xmidt-org/wrp-go/compare/v3.1.1...v3.1.2
 [v3.1.1]: https://github.com/xmidt-org/wrp-go/compare/v3.1.0...v3.1.1
 [v3.1.0]: https://github.com/xmidt-org/wrp-go/compare/v3.0.2...v3.1.0

utf8.go

@@ -0,0 +1,63 @@
+/**
+ * Copyright 2022 Comcast Cable Communications Management, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package wrp
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"unicode/utf8"
+)
+
+var (
+	ErrNotUTF8        = errors.New("field contains non-utf-8 characters")
+	ErrUnexpectedKind = errors.New("A struct or non-nil pointer to struct is required")
+)
+
+// UTF8 takes any struct verifies that it contains UTF-8 strings.
+func UTF8(v interface{}) error {
+	value := reflect.ValueOf(v)
+	if value.Kind() == reflect.Ptr && !value.IsNil() {
+		value = value.Elem()
+	}
+
+	if value.Kind() != reflect.Struct {
+		return fmt.Errorf("%w: %s", ErrUnexpectedKind, value.Kind())
+	}
+
+	for i := 0; i < value.NumField(); i++ {
+		ft := value.Type().Field(i)
+		if len(ft.PkgPath) > 0 || ft.Anonymous {
+			continue // skip embedded or unexported fields
+		}
+
+		f := value.Field(i)
+		if !f.CanInterface() {
+			continue // this should never happen, but ... you never know
+		}
+
+		if s, ok := f.Interface().(string); ok {
+			if !utf8.ValidString(s) {
+				return fmt.Errorf("%w: '%s:%v'", ErrNotUTF8, ft.Name, s)
+			}
+			fmt.Println(s)
+		}
+	}
+
+	return nil
+}

utf8_test.go

@@ -24,7 +24,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestInvalidUtf8(t *testing.T) {
+func TestInvalidUtf8Decoding(t *testing.T) {
 	assert := assert.New(t)
 
 	/*
@@ -48,10 +48,62 @@ func TestInvalidUtf8(t *testing.T) {
 	decoder := NewDecoderBytes(invalid, Msgpack)
 	msg := new(Message)
 	err := decoder.Decode(msg)
-
 	assert.Nil(err)
 	assert.True(utf8.ValidString(msg.Source))
 
-	/* This fails. */
-	assert.True(utf8.ValidString(msg.Destination))
+	assert.False(utf8.ValidString(msg.Destination))
+	err = UTF8(msg)
+	assert.ErrorIs(err, ErrNotUTF8)
+}
+
+func TestUTF8(t *testing.T) {
+	type Test struct {
+		unexported string
+		Name       string
+		Age        int
+	}
+
+	testVal := Test{
+		unexported: "this shouldn't be output",
+		Name:       "Joe Schmoe",
+		Age:        415,
+	}
+
+	tests := []struct {
+		description string
+		value       interface{}
+		expectedErr error
+	}{
+		{
+			description: "Success",
+			value:       testVal,
+		},
+		{
+			description: "Pointer success",
+			value:       &testVal,
+		},
+		{
+			description: "Non struct error",
+			value:       5,
+			expectedErr: ErrUnexpectedKind,
+		},
+		{
+			description: "UTF8 error",
+			value: Test{
+				Name: string([]byte{0xbf}),
+			},
+			expectedErr: ErrNotUTF8,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.description, func(t *testing.T) {
+			assert := assert.New(t)
+			err := UTF8(tc.value)
+			if tc.expectedErr == nil {
+				assert.NoError(err)
+				return
+			}
+			assert.ErrorIs(err, tc.expectedErr)
+		})
+	}
 }