From 8f1e60bb6a8bfe3820689a1a37c86294af5b61a8 Mon Sep 17 00:00:00 2001
From: Alexander Drozdov <snosme@gmail.com>
Date: Thu, 17 Dec 2020 00:42:07 +0200
Subject: [PATCH] respect account rules, wait tweak

---
 src/web/price-check/trade/RateLimiter.ts | 11 ++++++-
 src/web/price-check/trade/common.ts      | 38 ++++++++++++++----------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/src/web/price-check/trade/RateLimiter.ts b/src/web/price-check/trade/RateLimiter.ts
index 7aa70189..35df59ec 100644
--- a/src/web/price-check/trade/RateLimiter.ts
+++ b/src/web/price-check/trade/RateLimiter.ts
@@ -21,7 +21,7 @@ export class RateLimiter {
   private async _wait (borrow: boolean, immediate = true): Promise<boolean> {
     if (this._destroyed) throw new Error('RateLimiter is no longer active')
 
-    if (this.state.stack.length === this.max) {
+    if (this.state.stack.length >= this.max) {
       this.state.queue++
       await this.state.stack[0]
       this.state.queue--
@@ -43,6 +43,15 @@ export class RateLimiter {
     }))
   }
 
+  forceSmallWait () {
+    this.state.stack.unshift(new Promise((resolve) => {
+      setTimeout(() => {
+        this.state.stack.shift()
+        resolve()
+      }, 1.5 * 1000)
+    }))
+  }
+
   static async waitMulti (limiters: RateLimiter[]): Promise<void> {
     const res = await Promise.all(limiters.map(rl => rl.wait(false)))
     if (res.every(immediate => immediate)) {
diff --git a/src/web/price-check/trade/common.ts b/src/web/price-check/trade/common.ts
index 01c400c9..d74c28bb 100644
--- a/src/web/price-check/trade/common.ts
+++ b/src/web/price-check/trade/common.ts
@@ -71,28 +71,38 @@ export const RATE_LIMIT_RULES = {
   ]
 }
 
-export function adjustRateLimits (clientLimits: RateLimiter[], headers: Headers) { /* eslint-disable no-console */
-  const DEBUG = false
+export function adjustRateLimits (clientLimits: RateLimiter[], headers: Headers) {
+  if (!headers.has('x-rate-limit-rules')) return clientLimits
+
+  const rules = headers.get('x-rate-limit-rules')!.split(',')
+
+  return _adjustRateLimits(
+    clientLimits,
+    rules.map(rule => headers.get(`x-rate-limit-${rule}`)!).join(','),
+    rules.map(rule => headers.get(`x-rate-limit-${rule}-state`)!).join(',')
+  )
+}
+
+function _adjustRateLimits (clientLimits: RateLimiter[], limitStr: string, stateStr: string) { /* eslint-disable no-console */
+  const DEBUG = true
   const DESYNC_FIX = 1
 
-  if (!headers.has('x-rate-limit-ip') || !headers.get('x-rate-limit-ip-state')) return clientLimits
-
-  const limitIpState = headers.get('x-rate-limit-ip-state')!
+  const limitRuleState = stateStr
     .split(',')
     .map(rule => rule.split(':'))
     .map(rule => Number(rule[0]))
-  const limitIp = headers.get('x-rate-limit-ip')!
+  const limitRule = limitStr
     .split(',')
     .map(rule => rule.split(':'))
     .map((rule, idx) => ({
       max: Number(rule[0]),
-      window: Number(rule[1]) + (DESYNC_FIX + (idx + 1)),
-      state: limitIpState[idx]
+      window: Number(rule[1]) + DESYNC_FIX,
+      state: limitRuleState[idx]
     }))
 
   // destroy
   for (const limit of clientLimits) {
-    const isActive = limitIp.some(serverLimit => limit.isEqualLimit(serverLimit))
+    const isActive = limitRule.some(serverLimit => limit.isEqualLimit(serverLimit))
     if (!isActive) {
       limit.destroy()
       DEBUG && console.log('Destroy', limit.toString())
@@ -101,28 +111,26 @@ export function adjustRateLimits (clientLimits: RateLimiter[], headers: Headers)
 
   // filter active
   clientLimits = clientLimits.filter(limit =>
-    limitIp.some(serverLimit => limit.isEqualLimit(serverLimit))
+    limitRule.some(serverLimit => limit.isEqualLimit(serverLimit))
   )
 
   // compare client<>server state
   for (const limit of clientLimits) {
-    const serverLimit = limitIp.find(serverLimit => limit.isEqualLimit(serverLimit))!
+    const serverLimit = limitRule.find(serverLimit => limit.isEqualLimit(serverLimit))!
     const delta = (serverLimit.state - limit.state.stack.length)
 
     if (delta === 0) {
       DEBUG && console.log('Limits are in sync')
     } else if (delta > 0) {
       DEBUG && console.error(`Rate limit state on Server is greater by ${Math.abs(delta)}. Bursting to prevent rate limiting.`)
-      Array(delta).fill(undefined).forEach(() => {
-        limit.wait()
-      })
+      limit.forceSmallWait()
     } else if (delta < 0) {
       DEBUG && console.warn(`Rate limit state on Client is greater by ${Math.abs(delta)}`)
     }
   }
 
   // add new
-  for (const serverLimit of limitIp) {
+  for (const serverLimit of limitRule) {
     if (clientLimits.some(limit => limit.isEqualLimit(serverLimit))) continue
 
     const rl = new RateLimiter(serverLimit.max, serverLimit.window)