Current File : //proc/thread-self/root/opt/imunify360-webshield/lualib/resty/limit/count.lua
-- implement GitHub request rate limiting:
-- https://developer.github.com/v3/#rate-limiting
local ngx_shared = ngx.shared
local setmetatable = setmetatable
local assert = assert
local _M = {
_VERSION = '0.08'
}
local mt = {
__index = _M
}
local incr_support_init_ttl
local ngx_config = ngx.config
local ngx_lua_v = ngx.config.ngx_lua_version
if not ngx_config or not ngx_lua_v or (ngx_lua_v < 10012) then
incr_support_init_ttl = false
else
incr_support_init_ttl = true
end
-- the "limit" argument controls number of request allowed in a time window.
-- time "window" argument controls the time window in seconds.
function _M.new(dict_name, limit, window)
local dict = ngx_shared[dict_name]
if not dict then
return nil, "shared dict not found"
end
assert(limit > 0 and window > 0)
local self = {
dict = dict,
limit = limit,
window = window,
}
return setmetatable(self, mt)
end
-- incoming function using incr with init_ttl
-- need OpenResty version > v0.10.12rc2
local function incoming_new(self, key, commit)
local dict = self.dict
local limit = self.limit
local window = self.window
local remaining, ok, err
if commit then
remaining, err = dict:incr(key, -1, limit, window)
if not remaining then
return nil, err
end
else
remaining = (dict:get(key) or limit) - 1
end
if remaining < 0 then
return nil, "rejected"
end
return 0, remaining
end
-- incoming function using incr and expire
local function incoming_old(self, key, commit)
local dict = self.dict
local limit = self.limit
local window = self.window
local remaining, ok, err
if commit then
remaining, err = dict:incr(key, -1, limit)
if not remaining then
return nil, err
end
if remaining == limit - 1 then
ok, err = dict:expire(key, window)
if not ok then
if err == "not found" then
remaining, err = dict:incr(key, -1, limit)
if not remaining then
return nil, err
end
ok, err = dict:expire(key, window)
if not ok then
return nil, err
end
else
return nil, err
end
end
end
else
remaining = (dict:get(key) or limit) - 1
end
if remaining < 0 then
return nil, "rejected"
end
return 0, remaining
end
_M.incoming = incr_support_init_ttl and incoming_new or incoming_old
-- uncommit remaining and return remaining value
function _M.uncommit(self, key)
assert(key)
local dict = self.dict
local limit = self.limit
local remaining, err = dict:incr(key, 1)
if not remaining then
if err == "not found" then
remaining = limit
else
return nil, err
end
end
return remaining
end
return _M
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