1 files changed, 74 insertions, 0 deletions
diff --git a/pkg/types/string.go b/pkg/types/string.go
new file mode 100644
index 0000000..f8ead45
--- /dev/null
+++ b/pkg/types/string.go
@@ -0,0 +1,74 @@
+package types
+
+import (
+	"bytes"
+	"database/sql"
+	"database/sql/driver"
+	"encoding"
+	"encoding/json"
+	"github.com/icinga/icingadb/internal"
+	"strings"
+)
+
+// String adds JSON support to sql.NullString.
+type String struct {
+	sql.NullString
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+// Supports JSON null.
+func (s String) MarshalJSON() ([]byte, error) {
+	var v interface{}
+	if s.Valid {
+		v = s.String
+	}
+
+	return internal.MarshalJSON(v)
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (s *String) UnmarshalText(text []byte) error {
+	*s = String{sql.NullString{
+		String: string(text),
+		Valid:  true,
+	}}
+
+	return nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+// Supports JSON null.
+func (s *String) UnmarshalJSON(data []byte) error {
+	// Ignore null, like in the main JSON package.
+	if bytes.HasPrefix(data, []byte{'n'}) {
+		return nil
+	}
+
+	if err := internal.UnmarshalJSON(data, &s.String); err != nil {
+		return err
+	}
+
+	s.Valid = true
+
+	return nil
+}
+
+// Value implements the driver.Valuer interface.
+// Supports SQL NULL.
+func (s String) Value() (driver.Value, error) {
+	if !s.Valid {
+		return nil, nil
+	}
+
+	// PostgreSQL does not allow null bytes in varchar, char and text fields.
+	return strings.ReplaceAll(s.String, "\x00", ""), nil
+}
+
+// Assert interface compliance.
+var (
+	_ json.Marshaler           = String{}
+	_ encoding.TextUnmarshaler = (*String)(nil)
+	_ json.Unmarshaler         = (*String)(nil)
+	_ driver.Valuer            = String{}
+	_ sql.Scanner              = (*String)(nil)
+)