Admission check endpoint (#338)

Author: medjedovicm

CONFIGURATION.md

@@ -112,3 +112,6 @@ Running `nostream` for the first time creates the settings file in `<project_roo
 | limits.message.rateLimits[].period          | Rate limit period in milliseconds. |
 | limits.message.rateLimits[].rate            | Maximum number of messages during period. |
 | limits.message.ipWhitelist                  | List of IPs (IPv4 or IPv6) to ignore rate limits. |
+| limits.admissionCheck.rateLimits[].period          | Rate limit period in milliseconds. |
+| limits.admissionCheck.rateLimits[].rate            | Maximum number of admission checks during period. |
+| limits.admissionCheck.ipWhitelist                  | List of IPs (IPv4 or IPv6) to ignore rate limits. |

resources/default-settings.yaml

@@ -56,6 +56,15 @@ limits:
       - "::1"
       - "10.10.10.1"
       - "::ffff:10.10.10.1"
+  admissionCheck:
+    rateLimits:
+      - description: 30 admission checks/min or 1 check every 2 seconds
+        period: 60000
+        rate: 30
+    ipWhitelist:
+      - "::1"
+      - "10.10.10.1"
+      - "::ffff:10.10.10.1"
   connection:
     rateLimits:
       - period: 1000

src/@types/settings.ts

@@ -112,8 +112,14 @@ export interface InvoiceLimits {
   ipWhitelist?: string[]
 }
 
+export interface AdmissionCheckLimits {
+  rateLimits: RateLimit[]
+  ipWhitelist?: string[]
+}
+
 export interface Limits {
   invoice?: InvoiceLimits
+  admissionCheck?: AdmissionCheckLimits
   connection?: ConnectionLimits
   client?: ClientLimits
   event?: EventLimits

src/controllers/admission/get-admission-check-controller.ts

@@ -0,0 +1,70 @@
+import { Request, Response } from 'express'
+import { createLogger } from '../../factories/logger-factory'
+import { getRemoteAddress } from '../../utils/http'
+import { IController } from '../../@types/controllers'
+import { IRateLimiter } from '../../@types/utils'
+import { IUserRepository } from '../../@types/repositories'
+import { path } from 'ramda'
+import { Settings } from '../../@types/settings'
+
+const debug = createLogger('get-admission-check-controller')
+
+export class GetSubmissionCheckController implements IController {
+  public constructor(
+    private readonly userRepository: IUserRepository,
+    private readonly settings: () => Settings,
+    private readonly rateLimiter: () => IRateLimiter,
+  ){}
+
+  public async handleRequest(request: Request, response: Response): Promise<void> {
+    const currentSettings = this.settings()
+
+    const limited = await this.isRateLimited(request, currentSettings)
+    if (limited) {
+      response
+        .status(429)
+        .setHeader('content-type', 'text/plain; charset=utf8')
+        .send('Too many requests')
+      return
+    }
+    
+    const pubkey = request.params.pubkey
+    const user = await this.userRepository.findByPubkey(pubkey)
+
+    let userAdmitted = false
+
+    const minBalance = currentSettings.limits?.event?.pubkey?.minBalance
+    if (user && user.isAdmitted && (!minBalance || user.balance >= minBalance)) {
+      userAdmitted = true
+    }
+
+    response
+      .status(200)
+      .setHeader('content-type', 'application/json; charset=utf8')
+      .send({ userAdmitted })
+
+    return
+  }
+
+  public async isRateLimited(request: Request, settings: Settings) {
+    const rateLimits = path(['limits', 'admissionCheck', 'rateLimits'], settings)
+    if (!Array.isArray(rateLimits) || !rateLimits.length) {
+      return false
+    }
+
+    const ipWhitelist = path(['limits', 'admissionCheck', 'ipWhitelist'], settings)
+    const remoteAddress = getRemoteAddress(request, settings)
+
+    let limited = false
+    if (Array.isArray(ipWhitelist) && !ipWhitelist.includes(remoteAddress)) {
+      const rateLimiter = this.rateLimiter()
+      for (const { rate, period } of rateLimits) {
+        if (await rateLimiter.hit(`${remoteAddress}:admission-check:${period}`, 1, { period, rate })) {
+          debug('rate limited %s: %d in %d milliseconds', remoteAddress, rate, period)
+          limited = true
+        }
+      }
+    }
+    return limited
+  }
+}

src/factories/controllers/get-admission-check-controller-factory.ts

@@ -0,0 +1,16 @@
+import { createSettings } from '../settings-factory'
+import { getMasterDbClient } from '../../database/client'
+import { GetSubmissionCheckController } from '../../controllers/admission/get-admission-check-controller'
+import { slidingWindowRateLimiterFactory } from '../rate-limiter-factory'
+import { UserRepository } from '../../repositories/user-repository'
+
+export const createGetAdmissionCheckController = () => {
+  const dbClient = getMasterDbClient()
+  const userRepository = new UserRepository(dbClient)
+  
+  return new GetSubmissionCheckController(
+    userRepository,
+    createSettings,
+    slidingWindowRateLimiterFactory
+  )
+}

src/routes/admissions/index.ts

@@ -0,0 +1,10 @@
+import { createGetAdmissionCheckController } from '../../factories/controllers/get-admission-check-controller-factory'
+import { Router } from 'express'
+import { withController } from '../../handlers/request-handlers/with-controller-request-handler'
+
+const admissionRouter = Router()
+
+admissionRouter
+  .get('/check/:pubkey', withController(createGetAdmissionCheckController))
+
+export default admissionRouter

src/routes/index.ts

@@ -1,6 +1,7 @@
 import express from 'express'
 
 import { nodeinfo21Handler, nodeinfoHandler } from '../handlers/request-handlers/nodeinfo-handler'
+import admissionRouter from './admissions'
 import callbacksRouter from './callbacks'
 import { getHealthRequestHandler } from '../handlers/request-handlers/get-health-request-handler'
 import { getTermsRequestHandler } from '../handlers/request-handlers/get-terms-request-handler'
@@ -19,6 +20,7 @@ router.get('/nodeinfo/2.1', nodeinfo21Handler)
 router.get('/nodeinfo/2.0', nodeinfo21Handler)
 
 router.use('/invoices', rateLimiterMiddleware, invoiceRouter)
+router.use('/admissions', rateLimiterMiddleware, admissionRouter)
 router.use('/callbacks', rateLimiterMiddleware, callbacksRouter)
 
 export default router

src/routes/invoices/index.ts

@@ -12,4 +12,4 @@ invoiceRouter
   .get('/:invoiceId/status', withController(createGetInvoiceStatusController))
   .post('/', urlencoded({ extended: true }), withController(createPostInvoiceController))
 
-export default invoiceRouter
+export default invoiceRouter