handled errors better in JWK Set cache

Author: jricher

openid-connect-common/src/main/java/org/mitre/jwt/signer/service/impl/JWKSetCacheService.java

@@ -32,12 +32,14 @@
 import org.slf4j.LoggerFactory;
 import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
 import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestClientException;
 import org.springframework.web.client.RestTemplate;
 
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
 import com.google.common.util.concurrent.UncheckedExecutionException;
+import com.google.gson.JsonParseException;
 import com.nimbusds.jose.jwk.JWKSet;
 
 /**
@@ -136,14 +138,18 @@ private class JWKSetEncryptorFetcher extends CacheLoader<String, JWTEncryptionAn
  */
 @Override
 public JWTEncryptionAndDecryptionService load(String key) throws Exception {
-String jsonString = restTemplate.getForObject(key, String.class);
-JWKSet jwkSet = JWKSet.parse(jsonString);
-
-JWKSetKeyStore keyStore = new JWKSetKeyStore(jwkSet);
-
-JWTEncryptionAndDecryptionService service = new DefaultJWTEncryptionAndDecryptionService(keyStore);
-
-return service;
+try {
+String jsonString = restTemplate.getForObject(key, String.class);
+JWKSet jwkSet = JWKSet.parse(jsonString);
+
+JWKSetKeyStore keyStore = new JWKSetKeyStore(jwkSet);
+
+JWTEncryptionAndDecryptionService service = new DefaultJWTEncryptionAndDecryptionService(keyStore);
+
+return service;
+} catch (JsonParseException | RestClientException e) {
+throw new IllegalArgumentException("Unable to load JWK Set");
+}
 }
 }