Feat/add backend lambda functions

.github/workflows/backend.yml

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+name: Backend Tests
+on:
+  pull_request:
+    paths: [backend/**]
+  push:
+    branches: [main]
+    paths: [backend/**]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        working-directory: ./backend
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 18
+          cache: yarn
+          cache-dependency-path: backend/yarn.lock
+      - name: Install deps
+        run: yarn install --frozen-lockfile
+      - name: Prettier check
+        run: yarn prettier:check
+      - name: Lint
+        run: yarn lint
+      - name: Build
+        run: yarn build
+      - name: Test
+        run: yarn test

.github/workflows/frontend.yml

@@ -1,8 +1,10 @@
 name: Frontend Tests
 on:
   pull_request:
+    paths: [frontend/**]
   push:
     branches: [main]
+    paths: [frontend/**]
 
 jobs:
   test:

backend/.eslintrc

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+{
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "ecmaVersion": 2020,
+    "sourceType": "script"
+  },
+  "plugins": ["@typescript-eslint"],
+  "extends": ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
+  "rules": {
+    "no-undef": "off"
+  }
+}

backend/.gitignore

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+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+/dist
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# env
+.env
+
+# local env files
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo

backend/.prettierrc

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+{
+  "semi": false,
+  "singleQuote": true,
+  "trailingComma": "none"
+}

backend/.swcrc

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+{
+  "minify": false,
+  "jsc": {
+    "target": "es2016",
+    "parser": {
+      "syntax": "typescript",
+      "preserveAllComments": false
+    }
+  },
+  "module": {
+    "type": "commonjs",
+    "strict": true
+  }
+}

backend/README.md

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+# Backend
+
+This module contains two functions meant to be executed as AWS Lambda functions.
+
+## Run locally
+
+Set some env vars:
+
+```bash
+export DISPENSER_WALLET_KEY = [your, solana, private, key]
+export FUNDING_WALLET_KEY = [your, solana, private, key]
+```
+
+Then run:
+
+```bash
+yarn serve
+```
+
+Will expose two endpoints on localhost:8002:
+
+`GET /api/grant/v1/discord_signed_message` => signDiscordMessageHandler
+`POST /api/grant/v1/fund_transaction` => fundTransactionHandler
+
+## Deployment environment variables
+
+Following env vars are required:
+
+- `DISPENSER_KEY_SECRET_NAME`: private key of the wallet that will be used to sign the discord message
+- `FUNDER_WALLET_KEY_SECRET_NAME`: private key of the wallet that will be used to fund the transactions
+- `TOKEN_DISPENSER_PROGRAM_ID`: the program id of the token dispenser

backend/package.json

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+{
+  "name": "backend",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "build": "tsc --noemit && rm -rf dist && swc ./src -d ./dist --copy-files --ignore \"**/*.test.ts,**/__test__/**\"",
+    "lint": "eslint \"src/**/*.{json,js,jsx,ts,tsx}\" && tsc --noemit",
+    "prettier": "prettier \"./**/*.{json,js,jsx,ts,tsx}\" --write",
+    "prettier:check": "prettier \"./**/*.{json,js,jsx,ts,tsx}\" --check",
+    "test": "jest",
+    "test:coverage": "jest --coverage",
+    "serve": "node -r @swc-node/register src/serve.ts"
+  },
+  "dependencies": {
+    "@aws-sdk/client-secrets-manager": "^3.535.0",
+    "@coral-xyz/anchor": "^0.29.0",
+    "@solana/web3.js": "^1.91.1",
+    "tweetnacl": "^1.0.3"
+  },
+  "devDependencies": {
+    "@jest/globals": "^29.7.0",
+    "@swc-node/register": "^1.9.0",
+    "@swc/cli": "^0.3.10",
+    "@swc/core": "^1.4.8",
+    "@swc/jest": "^0.2.36",
+    "@swc/types": "^0.1.6",
+    "@types/aws-lambda": "^8.10.136",
+    "@types/express": "^4.17.21",
+    "@types/jest": "^29.5.12",
+    "@typescript-eslint/eslint-plugin": "^7.3.1",
+    "@typescript-eslint/parser": "^7.3.1",
+    "body-parser": "^1.20.2",
+    "eslint": "^8.57.0",
+    "express": "^4.19.1",
+    "jest": "^29.7.0",
+    "msw": "^2.2.9",
+    "prettier": "^2.7.1",
+    "typescript": "^5.4.2"
+  },
+  "jest": {
+    "transform": {
+      "^.+\\.(t|j)sx?$": "@swc/jest"
+    }
+  }
+}

backend/src/config.ts

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+export default {
+  discord: {
+    baseUrl: process.env.DISCORD_URL ?? 'https://discord.com'
+  },
+  aws: {
+    region: process.env.AWS_REGION ?? 'us-east-2'
+  },
+  tokenDispenserProgramId: () => process.env.TOKEN_DISPENSER_PROGRAM_ID,
+  keys: {
+    dispenserGuard: {
+      /** optional. mostly for local testing */
+      key: process.env.DISPENSER_WALLET_KEY,
+      /** required. with a default value and used when when key not set */
+      secretName:
+        process.env.DISPENSER_KEY_SECRET_NAME ?? 'xl-dispenser-guard-key'
+    },
+    funding: {
+      /** optional. mostly for local testing */
+      key: process.env.FUNDING_WALLET_KEY,
+      /** required. with a default value and used when when key not set */
+      secretName:
+        process.env.FUNDER_WALLET_KEY_SECRET_NAME ??
+        'xli-test-secret-funder-wallet'
+    }
+  }
+}

backend/src/handlers/discord-signed-digest.ts

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+import { Keypair, PublicKey } from '@solana/web3.js'
+import { getDispenserKey } from '../utils/secrets'
+import { APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda'
+import { getDiscordUser, signDiscordDigest } from '../utils/discord'
+import { HandlerError } from '../utils/errors'
+
+export interface DiscordSignedDigestParams {
+  publicKey: string
+}
+
+export const signDiscordMessage = async (
+  event: APIGatewayProxyEvent
+): Promise<APIGatewayProxyResult> => {
+  try {
+    const publicKey = (event.queryStringParameters ?? {})['publicKey']
+    validatePublicKey(publicKey)
+
+    const accessToken = event.headers['x-auth-token']
+    const discordId = await getDiscordId(accessToken)
+
+    const claimant = new PublicKey(publicKey!)
+    const dispenserGuard = await loadDispenserGuard()
+
+    const signedDigest = signDiscordDigest(discordId, claimant, dispenserGuard)
+
+    return {
+      statusCode: 200,
+      body: JSON.stringify({
+        signature: Buffer.from(signedDigest.signature).toString('hex'),
+        publicKey: Buffer.from(signedDigest.publicKey).toString('hex'), // The dispenser guard's public key
+        fullMessage: Buffer.from(signedDigest.fullMessage).toString('hex')
+      })
+    }
+  } catch (err: HandlerError | unknown) {
+    console.error('Error generating signed discord digest', err)
+    if (err instanceof HandlerError) {
+      return {
+        statusCode: err.statusCode,
+        body: JSON.stringify(err.body)
+      }
+    }
+
+    return {
+      statusCode: 500,
+      body: JSON.stringify({ error: 'Internal server error' })
+    }
+  }
+}
+
+async function loadDispenserGuard() {
+  const secretData = await getDispenserKey()
+  const dispenserGuardKey = secretData.key
+
+  const dispenserGuard = Keypair.fromSecretKey(
+    Uint8Array.from(dispenserGuardKey)
+  )
+
+  return dispenserGuard
+}
+
+function validatePublicKey(publicKey?: string) {
+  if (!publicKey) {
+    throw new HandlerError(400, {
+      error: "Must provide the 'publicKey' query parameter"
+    })
+  }
+
+  if (typeof publicKey !== 'string') {
+    throw new HandlerError(400, {
+      error: "Invalid 'publicKey' query parameter"
+    })
+  }
+
+  try {
+    new PublicKey(publicKey)
+  } catch {
+    throw new HandlerError(400, {
+      error: "Invalid 'publicKey' query parameter"
+    })
+  }
+}
+
+async function getDiscordId(accessToken?: string) {
+  if (!accessToken) {
+    throw new HandlerError(400, { error: 'Must provide discord auth token' })
+  }
+
+  try {
+    const user = await getDiscordUser(accessToken)
+    return user.id
+  } catch (err) {
+    throw new HandlerError(403, { error: 'Invalid discord access token' })
+  }
+}

backend/src/handlers/fund-transactions.ts

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+import NodeWallet from '@coral-xyz/anchor/dist/cjs/nodewallet'
+import { APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda'
+import { getFundingKey } from '../utils/secrets'
+import {
+  checkTransactions,
+  deserializeTransactions
+} from '../utils/fund-transactions'
+import { Keypair } from '@solana/web3.js'
+import { HandlerError } from '../utils/errors'
+
+export type FundTransactionRequest = Uint8Array[]
+
+export const fundTransactions = async (
+  event: APIGatewayProxyEvent
+): Promise<APIGatewayProxyResult> => {
+  try {
+    const requestBody = JSON.parse(event.body!)
+    validateFundTransactions(requestBody)
+    const transactions = deserializeTransactions(requestBody)
+    const isTransactionsValid = await checkTransactions(transactions)
+
+    if (!isTransactionsValid) {
+      return {
+        statusCode: 403,
+        body: JSON.stringify({ error: 'Unauthorized transactions' })
+      }
+    }
+
+    const wallet = await loadFunderWallet()
+
+    const signedTransactions = await wallet.signAllTransactions(transactions)
+    return {
+      statusCode: 200,
+      body: JSON.stringify(
+        signedTransactions.map((tx) => Buffer.from(tx.serialize()))
+      )
+    }
+  } catch (err: HandlerError | unknown) {
+    console.error('Error signing transactions', err)
+
+    if (err instanceof HandlerError) {
+      return {
+        statusCode: err.statusCode,
+        body: JSON.stringify(err.body)
+      }
+    }
+
+    return {
+      statusCode: 500,
+      body: JSON.stringify({ error: 'Internal server error' })
+    }
+  }
+}
+
+function validateFundTransactions(transactions: unknown) {
+  if (!Array.isArray(transactions) || transactions.length === 0) {
+    throw new HandlerError(400, { error: 'Must provide transactions' })
+  }
+
+  if (transactions.length >= 10) {
+    throw new HandlerError(400, { error: 'Too many transactions' })
+  }
+}
+
+async function loadFunderWallet(): Promise<NodeWallet> {
+  const secretData = await getFundingKey()
+  const funderWalletKey = secretData.key
+
+  const keypair = Keypair.fromSecretKey(new Uint8Array(funderWalletKey))
+
+  return new NodeWallet(keypair)
+}