# Store massages in MsSQL
**URL:** https://community.hivemq.com/t/store-massages-in-mssql/301
**Category:** HiveMQ Extension SDK
**Created:** [August 11, 2020, 9:11pm UTC](https://community.hivemq.com/t/store-massages-in-mssql/301 "2020-08-11T21:11:21Z")
**Posts on this page:** 1
**Showing post:** 5
### Author:  [@FloLi](https://community.hivemq.com/u/FloLi)
#### Post date: [August 18, 2020, 11:35am UTC](https://community.hivemq.com/t/store-massages-in-mssql/301/5 "2020-08-18T11:35:41Z")
> [@Misiu](#):
>
> Not sure if the second is possible, but ideally when subscribing with + the extension should subscribe the user to all topics he has access to.
the “+/temperature” would be possible if you implement a `SubscriptionAuthorizer` and register it with the `securityRegistry` mentioned by @michael_w
one important thing is, that you prevent the subscribe itself, as MQTT will handle this subscribe as a wildcard subscribe for “any/temperature”.
Here is an example how the prevention could be accomplished followed by adding subscriptions where the client has access to:
```
...
final List topicsIHaveAccessTo = new ArrayList<>();
topicsIHaveAccessTo.add("myClientId/temperature");
topicsIHaveAccessTo.add("clientIdOfAFriend/temperature");
topicsIHaveAccessTo.add("clientIdOfAnotherFriend/temperature");
final SubscriptionAuthorizer subAuthor = new SubscriptionAuthorizer() {
@Override
public void authorizeSubscribe(final @NotNull SubscriptionAuthorizerInput input, final @NotNull SubscriptionAuthorizerOutput output) {
final String topic = input.getSubscription().getTopicFilter();
final Qos qos = input.getSubscription().getQos();
final String clientId = input.getClientInformation().getClientId();
if(topic.startsWith("+/")){
//first let the original subscription fail.
output.failAuthorization();
//then add subscriptions through the store
for (final String topicWithAccess : topicsIHaveAccessTo) {
final TopicSubscription topicSubscription = Builders.topicSubscription()
.topicFilter(topicWithAccess)
.qos(qos)
.build();
Services.subscriptionStore().addSubscription(clientId, topicSubscription);
}
}
}
};
Services.securityRegistry().setAuthorizerProvider(new AuthorizerProvider() {
@Override
public Authorizer getAuthorizer(final @NotNull AuthorizerProviderInput authorizerProviderInput) {
return subAuthor;
}
});
```
I hope this could help.
Kind regards,
Flo
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