Added error handling if resumption token is not a valid base64 string

xoai-common/src/main/java/io/gdcc/xoai/services/impl/SimpleResumptionTokenFormat.java

@@ -124,12 +124,16 @@ public String format(ResumptionToken.Value resumptionToken) {
  * @param value The Base64 encoded string
  * @return A decoded String (may be empty)
  */
- static String base64Decode(String value) {
+ static String base64Decode(String value) throws BadResumptionTokenException {
  if (value == null) {
  return null;
  }
- byte[] decodedValue = Base64.getDecoder().decode(value);
- return new String(decodedValue, StandardCharsets.UTF_8);
+ try {
+ byte[] decodedValue = Base64.getDecoder().decode(value);
+ return new String(decodedValue, StandardCharsets.UTF_8);
+ } catch (IllegalArgumentException e) {
+ throw new BadResumptionTokenException("Token has no valid base64 encoding", e);
+ }
  }
 
  static String base64Encode(String value) {

xoai-common/src/test/java/io/gdcc/xoai/services/impl/SimpleResumptionTokenFormatTest.java

@@ -9,6 +9,7 @@
 import java.time.Instant;
 import java.time.temporal.ChronoUnit;
 import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -73,4 +74,16 @@ void validParse(String token) {
  String encoded = SimpleResumptionTokenFormat.base64Encode(token);
  assertDoesNotThrow(() -> format.parse(encoded));
  }
+
+ @Test
+ void validBase64Decoding() {
+ assertDoesNotThrow(() -> SimpleResumptionTokenFormat.base64Decode("b2Zmc2V0OjoxMDA="));
+ }
+
+ @Test
+ void invalidBase64Decoding() {
+ assertThrows(
+ BadResumptionTokenException.class,
+ () -> SimpleResumptionTokenFormat.base64Decode("b2Zmc2V0OjoMDA="));
+ }
 }