How to use

retrieveResource

method

in

com.nimbusds.jose.util.ResourceRetriever

  private JWKSet retrieveJwkSet(String endpointUrl) {
    Resource res;
    try {
      res = resourceRetriever.retrieveResource(new URL(endpointUrl));
    } catch (IOException e) {
      throw new IllegalStateException("Couldn't retrieve remote jwk set from: " + endpointUrl, e);
    }

    try {
      JWKSet.parse(res.getContent());
      return JWKSet.parse(res.getContent());
    } catch (java.text.ParseException e) {
      throw new IllegalStateException(e);
    }
  }
}

  res = resourceRetriever.retrieveResource(new URL(resourceServer.getEndpointUrl()));
} catch (IOException e) {
  throw new IllegalStateException("Couldn't retrieve remote metadata: " + e.getMessage(), e);

/**
 * Updates the cached JWK set from the configured URL.
 *
 * @return The updated JWK set.
 *
 * @throws RemoteKeySourceException If JWK retrieval failed.
 */
private JWKSet updateJWKSetFromURL()
  throws RemoteKeySourceException {
  Resource res;
  try {
    res = jwkSetRetriever.retrieveResource(jwkSetURL);
  } catch (IOException e) {
    throw new RemoteKeySourceException("Couldn't retrieve remote JWK set: " + e.getMessage(), e);
  }
  JWKSet jwkSet;
  try {
    jwkSet = JWKSet.parse(res.getContent());
  } catch (java.text.ParseException e) {
    throw new RemoteKeySourceException("Couldn't parse remote JWK set: " + e.getMessage(), e);
  }
  jwkSetCache.put(jwkSet);
  return jwkSet;
}

@Override
protected void internalInit() {
  // checks
  CommonHelper.assertNotBlank("clientId", getClientId());
  if (!AUTHORIZATION_CODE_FLOWS.contains(responseType) && !IMPLICIT_FLOWS.contains(responseType)
    && !HYBRID_CODE_FLOWS.contains(responseType)) {
    throw new TechnicalException("Unsupported responseType: " + responseType);
  }
  // except for the implicit flow, the secret is mandatory
  if (!IMPLICIT_FLOWS.contains(responseType)) {
    CommonHelper.assertNotBlank("secret", getSecret());
  }
  if (this.getDiscoveryURI() == null && this.getProviderMetadata() == null) {
    throw new TechnicalException("You must define either the discovery URL or directly the provider metadata");
  }
  // default value
  if (getResourceRetriever() == null) {
    setResourceRetriever(new DefaultResourceRetriever(getConnectTimeout(),getReadTimeout()));
  }
  if (this.getProviderMetadata() == null) {
    CommonHelper.assertNotBlank("discoveryURI", getDiscoveryURI());
    try {
      // Download OIDC metadata
      this.setProviderMetadata(OIDCProviderMetadata.parse(getResourceRetriever().retrieveResource(
          new URL(this.getDiscoveryURI())).getContent()));
    } catch (final IOException | ParseException e) {
      throw new TechnicalException(e);
    }
  }
}