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local http_rq = require 'http.request'
local json = require 'json'
local lmdb = require 'lmdb'
local M = {}
local db
local function get_db()
if db then
return db
end
db = assert(lmdb.open("data/cache.mdb", {nosubdir = true, mapsize = 2^20}))
return db
end
function M.lookup(domain)
if not domain:match "^[%w_%-%.]+$" then
return nil, "invalid service name!"
end
domain = domain:gsub('%.+', ".")
local db = get_db()
local txn = db:txn_begin()
if txn then
local cache = txn:open()
if cache[domain] then
local sv = json.decode(cache[domain])
if os.time() <= sv.expires then
txn:commit()
return sv
end
end
txn:commit()
end
local meta_uri = "https://"..domain.."/.well-known/citrons/auth"
local rq = http_rq.new_from_uri(meta_uri)
local headers, stream = rq:go(8)
if not headers then return nil, stream end
if headers:get ":status" ~= "200" then
return nil, "HTTP error: "..headers:get ":status"
end
local data, err = stream:get_body_chars(4096, 4)
if not data then return nil, err end
local ok, result = pcall(json.decode, data)
if not ok then return nil, "could not decode JSON" end
local txn = db:txn_begin(true)
if txn then
local cache = txn:open()
result.expires = os.time() + (result.ttl or 300)
cache[domain] = json.encode(result)
pcall(txn.commit, txn)
end
return result
end
return M
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