nitter/src/tokens.nim
2021-12-27 02:37:38 +01:00

105 lines
2.8 KiB
Nim

# SPDX-License-Identifier: AGPL-3.0-only
import asyncdispatch, httpclient, times, sequtils, json, math, random
import strutils, strformat
import zippy
import types, agents, consts, http_pool
const
expirationTime = 3.hours
maxLastUse = 1.hours
resetPeriod = 15.minutes
failDelay = initDuration(minutes=30)
var
clientPool {.threadvar.}: HttpPool
tokenPool {.threadvar.}: seq[Token]
lastFailed: Time
proc getPoolInfo*: string =
if tokenPool.len == 0: return "token pool empty"
let avg = tokenPool.mapIt(it.remaining).sum() div tokenPool.len
return &"{tokenPool.len} tokens, average remaining: {avg}"
proc rateLimitError*(): ref RateLimitError =
newException(RateLimitError, "rate limited with " & getPoolInfo())
proc fetchToken(): Future[Token] {.async.} =
if getTime() - lastFailed < failDelay:
raise rateLimitError()
let headers = newHttpHeaders({
"accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
"accept-encoding": "gzip",
"accept-language": "en-US,en;q=0.5",
"connection": "keep-alive",
"user-agent": getAgent(),
"authorization": auth
})
var
resp: string
tokNode: JsonNode
tok: string
try:
resp = clientPool.use(headers): await c.postContent(activate)
tokNode = parseJson(uncompress(resp))["guest_token"]
tok = tokNode.getStr($(tokNode.getInt))
let time = getTime()
result = Token(tok: tok, remaining: 187, reset: time + resetPeriod,
init: time, lastUse: time)
except Exception as e:
lastFailed = getTime()
echo "fetching token failed: ", e.msg
template expired(token: Token): untyped =
let time = getTime()
token.init < time - expirationTime or
token.lastUse < time - maxLastUse
template isLimited(token: Token): untyped =
token == nil or (token.remaining <= 5 and token.reset > getTime()) or
token.expired
proc release*(token: Token; invalid=false) =
if token != nil and (invalid or token.expired):
let idx = tokenPool.find(token)
if idx > -1: tokenPool.delete(idx)
proc getToken*(): Future[Token] {.async.} =
for i in 0 ..< tokenPool.len:
if not result.isLimited: break
release(result)
result = tokenPool.sample()
if result.isLimited:
release(result)
result = await fetchToken()
tokenPool.add result
if result == nil:
raise rateLimitError()
proc poolTokens*(amount: int) {.async.} =
var futs: seq[Future[Token]]
for i in 0 ..< amount:
futs.add fetchToken()
for token in futs:
var newToken: Token
try: newToken = await token
except: discard
if newToken != nil:
tokenPool.add newToken
proc initTokenPool*(cfg: Config) {.async.} =
clientPool = HttpPool()
while true:
if tokenPool.countIt(not it.isLimited) < cfg.minTokens:
await poolTokens(min(4, cfg.minTokens - tokenPool.len))
await sleepAsync(2000)