import { slidingWindowLimitScript } from "https://deno.land/x/upstash_ratelimit@v1.2.1/src/lua-scripts/single.ts";
type
`
local currentKey = KEYS[1] -- identifier including prefixes
local previousKey = KEYS[2] -- key of the previous bucket
local tokens = tonumber(ARGV[1]) -- tokens per window
local now = ARGV[2] -- current timestamp in milliseconds
local window = ARGV[3] -- interval in milliseconds
local incrementBy = ARGV[4] -- increment rate per request at a given value, default is 1
local requestsInCurrentWindow = redis.call("GET", currentKey)
if requestsInCurrentWindow == false then
requestsInCurrentWindow = 0
end
local requestsInPreviousWindow = redis.call("GET", previousKey)
if requestsInPreviousWindow == false then
requestsInPreviousWindow = 0
end
local percentageInCurrent = ( now % window ) / window
-- weighted requests to consider from the previous window
requestsInPreviousWindow = math.floor(( 1 - percentageInCurrent ) * requestsInPreviousWindow)
if requestsInPreviousWindow + requestsInCurrentWindow >= tokens then
return -1
end
local newValue = redis.call("INCRBY", currentKey, incrementBy)
if newValue == tonumber(incrementBy) then
-- The first time this key is set, the value will be equal to incrementBy.
-- So we only need the expire command once
redis.call("PEXPIRE", currentKey, window * 2 + 1000) -- Enough time to overlap with a new window + 1 second
end
return tokens - ( newValue + requestsInPreviousWindow )
`