1 files changed, 56 insertions, 0 deletions
diff --git a/utils/jsonutils/json.go b/utils/jsonutils/json.go
new file mode 100644
index 000000000..da77a2b6b
--- /dev/null
+++ b/utils/jsonutils/json.go
@@ -0,0 +1,56 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package jsonutils
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/pkg/errors"
+)
+
+type HumanizedJsonError struct {
+	Err       error
+	Line      int
+	Character int
+}
+
+func (e *HumanizedJsonError) Error() string {
+	return e.Err.Error()
+}
+
+// HumanizeJsonError extracts error offsets and annotates the error with useful context
+func HumanizeJsonError(err error, data []byte) error {
+	if syntaxError, ok := err.(*json.SyntaxError); ok {
+		return NewHumanizedJsonError(syntaxError, data, syntaxError.Offset)
+	} else if unmarshalError, ok := err.(*json.UnmarshalTypeError); ok {
+		return NewHumanizedJsonError(unmarshalError, data, unmarshalError.Offset)
+	} else {
+		return err
+	}
+}
+
+func NewHumanizedJsonError(err error, data []byte, offset int64) *HumanizedJsonError {
+	if err == nil {
+		return nil
+	}
+
+	if offset < 0 || offset > int64(len(data)) {
+		return &HumanizedJsonError{
+			Err: errors.Wrapf(err, "invalid offset %d", offset),
+		}
+	}
+
+	lineSep := []byte{'\n'}
+
+	line := bytes.Count(data[:offset], lineSep) + 1
+	lastLineOffset := bytes.LastIndex(data[:offset], lineSep)
+	character := int(offset) - (lastLineOffset + 1) + 1
+
+	return &HumanizedJsonError{
+		Line:      line,
+		Character: character,
+		Err:       errors.Wrapf(err, "parsing error at line %d, character %d", line, character),
+	}
+}