Question 273087 in Redis Question posted in
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Redis – check if HGetAll is found

Is it possible to check straight away if the key was found before doing more processing on the result?

res := client.HGetAll(ctx, key)
err := res.Err()
if err != nil {
    panic("Redis hgetall: "+err.Error())
}

When fetching a key you can do err == redis.Nil

value, err := client.Get(ctx, key).Result()
empty := err == redis.Nil
if err != nil && !empty {
    panic("Redis get: "+err.Error())
}
return value, !empty
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2

Answers


  1. 0

    Assuming the key does not exist:

    For the GET command, redis-server does return a (nil) response hence you can check for the redis.Nil error.

    For the HGETALL command, redis-server will return something along the lines of (empty list or set) which is not the same as nil hence why the library authors (go-redis) may have decided that it is not worthy of returning a redis.Nil error (or any similar error).

    Your best bet would be to check if the returned "list or set" (res.Val()) is empty.

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  2. 0

    Yes. Here is an example of how to find the state of the operation:

    val, err := rdb.Get(ctx, "key").Result()
switch {
case err == redis.Nil:
    fmt.Println("key does not exist")
case err != nil:
    fmt.Println("Get failed", err)
case val == "":
    fmt.Println("value is empty")
}

    Read more in go-redis docs

    You can also use Exists to check if a key exists.

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