--- a/pkg/models/common.go	Thu Jun 24 19:24:21 2021 +0200
+++ b/pkg/models/common.go	Thu Jun 24 22:13:48 2021 +0200
@@ -18,6 +18,7 @@
 	"encoding/json"
 	"errors"
 	"fmt"
+	"regexp"
 	"strings"
 	"time"
 
@@ -40,6 +41,9 @@
 	Country string
 	// UniqueCountries is a list of unique countries.
 	UniqueCountries []Country
+
+	// SafePath should only contain chars that directory traversal safe.
+	SafePath string
 )
 
 func (d Date) MarshalJSON() ([]byte, error) {
@@ -149,3 +153,25 @@
 	}
 	return b.String()
 }
+
+const SafePathExp = "[a-zA-Z0-9_-]+"
+
+var safePathRegExp = regexp.MustCompile("^" + SafePathExp + "$")
+
+func (sp SafePath) Valid() bool {
+	return safePathRegExp.MatchString(string(sp))
+}
+
+// UnmarshalJSON ensures that the given string only consist
+// of runes that are directory traversal safe.
+func (sp *SafePath) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	if c := SafePath(s); c.Valid() {
+		*sp = c
+		return nil
+	}
+	return fmt.Errorf("'%s' is not a safe path", s)
+}