setjsonkey.lua

-- Set a key containing JSON in Redis
local key = KEYS[1];
local name = ARGV[1];
local value = ARGV[2];

local data = redis.call('GET', key);
local json;

if not data then
    json = {};
else
   json = cjson.decode(data);
end

json[name] = value;
redis.call('SET', key, cjson.encode(json));
return cjson.encode(json);