Add exists command support #152
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alirezameskin
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| @@ -26,6 +26,7 @@ trait StringCommands[F[_], K, V] | |||
| with Increment[F, K, V] | |||
| with Bits[F, K, V] { | |||
| def del(key: K*): F[Unit] | |||
| def exists(key: K*): F[Long] | |||
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I think it would be better if we return F[Boolean] since Redis would return either 1 if the key exists or 0 if it doesn't, and that can be easily matched to true and false.
On the other hand, I don't really like what Redis does with accepting multiple keys as input. It'll just return the sum of the partial results. For example:
redis> SET key1 "Hello"
"OK"
redis> EXISTS key1
(integer) 1
redis> EXISTS nosuchkey
(integer) 0
redis> SET key2 "World"
"OK"
redis> EXISTS key1 key2 nosuchkey
(integer) 2
I think we could do better and return true if ALL the keys exist and false if at least one key doesn't exist. Similar to what the Monoid[All] instance would do.
What do you think?
Yes, we could do that in another PR :) |
I can work on it if you agree |
Sure @alirezameskin ! I was trying to follow how the commands are grouped in the Redis site. For example, here are all the String commands: https://redis.io/commands#string But as you can see, it doesn't always make sense. e.g. Feel free to propose what you have in mind and we can discuss it :) |
closes #151