RedisClient to use Lua script with EVAL command

Question

I am using nekipelov/redisclient to access Redis and I need to retrieve multiple hash data with one call to Redis to increase performance.

More specific, I am trying to retrieve multiple hashes like below:

redis-cli --ldb --eval /tmp/script.lua hash_key1 hash_key2

where script.lua:

local r = {}
for _, v in pairs(KEYS) do
r[#r+1] = redis.call('HGETALL', v)
end
return r

But I have difficulty to express the above by using EVAL command through nekipelov/redisclient.

I tried something below:

redisclient.command("EVAL", {"/tmp/script.lua", hash_key1, hash_key2}

but obviously is wrong.

Answer 1

I found the solution and the problem appeared on how I constructed the EVAL command in redisclient - I was passing the Lua script as a file:

const std::string script = 
            "local r = {} "
            "for _, v in pairs(KEYS) do "
            "r[#r+1] = redis.call('HGETALL', v) "
            "end "
            "return r ";

const unsigned int numKeys = 2;
const std::string key1 = "hash_key1";
const std::string key2 = "hash_key2";

result = redisclient.command("EVAL", {script, std::to_string(numKeys), key1, key2});