2.7 KiB
Database Handling
AbilityBots come with an embedded DB. Users are free to implement their own databases via implementing the DBContext class. The abstraction has multiple constructors to accommodate user-defined implementations of DBContext and MessageSender. We'll talk about the message sender interface in the Bot Testing section.
Example
We'll be introducing an ability that maintains a special counter for every user. At every /increment, the user will receive a message with the previous number + 1. We'll initially start from zero and increment upwards.
/**
* Use the database to fetch a count per user and increments.
* <p>
* Use /count to experiment with this ability.
*/
public Ability useDatabaseToCountPerUser() {
return Ability.builder()
.name("count")
.info("Increments a counter per user")
.privacy(PUBLIC)
.locality(ALL)
.input(0)
.action(ctx -> {
// db.getMap takes in a string, this must be unique and the same everytime you want to call the exact same map
// TODO: Using integer as a key in this db map is not recommended, it won't be serialized/deserialized properly if you ever decide to recover/backup db
Map<String, Integer> countMap = db.getMap("COUNTERS");
int userId = ctx.user().getId();
// Get and increment counter, put it back in the map
Integer counter = countMap.compute(String.valueOf(userId), (id, count) -> count == null ? 1 : ++count);
/*
Without lambdas implementation of incrementing
int counter;
if (countMap.containsKey(userId))
counter = countMap.get(userId) + 1;
else
counter = 1;
countMap.put(userId, counter);
*/
// Send formatted will enable markdown
String message = String.format("%s, your count is now *%d*!", ctx.user().getUserName(), counter);
silent.send(message, ctx.chatId());
})
.build();
}
After successfully adding that ability to your bot, try to /count and watch as the number increases at every message.
Other important functions in the db object:
- getSet - gets a set of data
- getList - gets a list of data
- summary - gets a summary of the present structs
Be sure to check out DBContext for all the implemented methods.