Support ERC-4646 token vaults

Author: gskril

server/src/db/index.ts

@@ -33,6 +33,8 @@ interface TokenRow {
   name: string
   symbol: string
   decimals: number
+  erc4626AssetAddress: Address | null
+  erc4626AssetDecimals: number | null
 }
 
 interface BalanceRow {
@@ -71,8 +73,17 @@ async function createDatabase() {
     provider: migrator,
   })
 
-  await doit.migrateToLatest()
-  console.log('Ran db migrations')
+  const { results } = await doit.migrateToLatest()
+
+  if (results) {
+    if (results.some((r) => r.status === 'Error')) {
+      console.error('Failed migrations:', results)
+      process.exit(1)
+    } else {
+      console.log('Ran db migrations')
+    }
+  }
+
   return db
 }
 

server/src/db/migrations/002_erc4626.ts

@@ -0,0 +1,27 @@
+import { Kysely } from 'kysely'
+
+// Add columns to `tokens` to track ERC4626 assets
+// Note: SQLite doesn't seem to support adding multiple columns in a single query
+export const up = async (db: Kysely<any>) => {
+  await db.schema
+    .alterTable('tokens')
+    .addColumn('erc4626AssetAddress', 'text')
+    .execute()
+
+  await db.schema
+    .alterTable('tokens')
+    .addColumn('erc4626AssetDecimals', 'integer')
+    .execute()
+}
+
+export const down = async (db: Kysely<any>) => {
+  await db.schema
+    .alterTable('tokens')
+    .dropColumn('erc4626AssetAddress')
+    .execute()
+
+  await db.schema
+    .alterTable('tokens')
+    .dropColumn('erc4626AssetDecimals')
+    .execute()
+}

server/src/db/migrator.ts

@@ -5,8 +5,9 @@ import type { MigrationProvider } from 'kysely'
 // a directory of migrators as plain JavaScript files, which isn't true in Bun,
 // in both dev mode and single-file executable mode.
 import * as m1 from './migrations/001_initial_migrations'
+import * as m2 from './migrations/002_erc4626'
 
-const migrations = [m1]
+const migrations = [m1, m2]
 
 export const migrator: MigrationProvider = {
   async getMigrations() {

server/src/handlers/tokens.ts

@@ -1,5 +1,11 @@
 import type { Context } from 'hono'
-import { type Address, erc20Abi, isAddress, zeroAddress } from 'viem'
+import {
+  type Address,
+  erc20Abi,
+  erc4626Abi,
+  isAddress,
+  zeroAddress,
+} from 'viem'
 import { z } from 'zod'
 
 import { getViemClient } from '../chains'
@@ -54,14 +60,15 @@ export async function addToken(c: Context) {
 
     const contract = {
       address,
-      abi: erc20Abi,
+      abi: [...erc20Abi, ...erc4626Abi],
     }
 
-    const [name, symbol, decimals] = await client.multicall({
+    const [name, symbol, decimals, erc4626Asset] = await client.multicall({
       contracts: [
         { ...contract, functionName: 'name' },
         { ...contract, functionName: 'symbol' },
         { ...contract, functionName: 'decimals' },
+        { ...contract, functionName: 'asset' },
       ],
       // This is needed when a `chain` object is not provided to viem
       // Using deployments from https://github.com/mds1/multicall3
@@ -72,6 +79,16 @@ export async function addToken(c: Context) {
       return c.json({ error: 'Failed to fetch token data' }, 409)
     }
 
+    let erc4626AssetDecimals: number | null = null
+
+    if (erc4626Asset.result) {
+      erc4626AssetDecimals = await client.readContract({
+        abi: erc20Abi,
+        address: erc4626Asset.result,
+        functionName: 'decimals',
+      })
+    }
+
     await db
       .insertInto('tokens')
       .values({
@@ -80,6 +97,8 @@ export async function addToken(c: Context) {
         name: name.result,
         symbol: symbol.result,
         decimals: decimals.result,
+        erc4626AssetAddress: erc4626Asset.result,
+        erc4626AssetDecimals,
       })
       .onConflict((oc) => oc.doNothing())
       .execute()

server/src/queues/workers/erc20.ts

@@ -1,6 +1,6 @@
 import type { Job } from 'bullmq'
 import type { Insertable } from 'kysely'
-import { type Address, erc20Abi, formatUnits } from 'viem'
+import { type Address, erc20Abi, erc4626Abi, formatUnits } from 'viem'
 
 import { getViemClient } from '../../chains'
 import { type Tables, db } from '../../db'
@@ -19,12 +19,13 @@ type JobData = {
 export const erc20Queue = createQueue<JobData>('erc20')
 createWorker<JobData>(erc20Queue, processJob)
 
+// TODO: Refactor this code such that offchain accounts can support ERC-4626. Currently it only supports onchain accounts.
 async function processJob(job: Job<JobData>) {
   const client = await getViemClient(job.data.chainId)
 
   const token = await db
     .selectFrom('tokens')
-    .select(['id', 'decimals'])
+    .select(['id', 'decimals', 'erc4626AssetAddress', 'erc4626AssetDecimals'])
     .where('address', '=', job.data.token)
     .where('chain', '=', job.data.chainId)
     .executeTakeFirst()
@@ -36,6 +37,11 @@ async function processJob(job: Job<JobData>) {
   // Formatted balance, not the full bigint
   let balance: number
 
+  // Handle ERC4626
+  const isErc4626 = !!token.erc4626AssetAddress
+  const effectiveAddress = token.erc4626AssetAddress ?? job.data.token
+  const effectiveDecimals = token.erc4626AssetDecimals ?? token.decimals
+
   if (job.data.owner.address) {
     // Handle onchain account
     const rawBalance = await client.readContract({
@@ -45,7 +51,41 @@ async function processJob(job: Job<JobData>) {
       args: [job.data.owner.address],
     })
 
-    balance = Number(formatUnits(rawBalance, token.decimals))
+    if (isErc4626) {
+      // Handle ERC-4626 which provides a standard way to get the underlying asset of a yield-bearing token
+      const underlyingAssetBalance = await client.readContract({
+        abi: erc4626Abi,
+        address: job.data.token,
+        functionName: 'convertToAssets',
+        args: [rawBalance],
+      })
+      balance = Number(formatUnits(underlyingAssetBalance, effectiveDecimals))
+    } else {
+      balance = Number(formatUnits(rawBalance, effectiveDecimals))
+    }
+
+    const rateToEth = await getRateToEth({
+      address: effectiveAddress,
+      chainId: job.data.chainId,
+      decimals: effectiveDecimals,
+    })
+
+    const data: Insertable<Tables['balances']> = {
+      token: token.id,
+      owner: job.data.owner.id,
+      balance,
+      ethValue: balance * rateToEth,
+    }
+
+    await db
+      .insertInto('balances')
+      .values(data)
+      .onConflict((oc) =>
+        oc
+          .columns(['token', 'owner'])
+          .doUpdateSet({ ...data, updatedAt: new Date().toISOString() })
+      )
+      .execute()
   } else {
     // Handle manual account (without an address)
     const balanceFromDb = await db
@@ -60,28 +100,28 @@ async function processJob(job: Job<JobData>) {
     }
 
     balance = balanceFromDb.balance
-  }
 
-  const rateToEth = await getRateToEth({
-    address: job.data.token,
-    chainId: job.data.chainId,
-    decimals: token.decimals,
-  })
-
-  const data: Insertable<Tables['balances']> = {
-    token: token.id,
-    owner: job.data.owner.id,
-    balance,
-    ethValue: balance * rateToEth,
-  }
+    const rateToEth = await getRateToEth({
+      address: job.data.token,
+      chainId: job.data.chainId,
+      decimals: token.decimals,
+    })
 
-  await db
-    .insertInto('balances')
-    .values(data)
-    .onConflict((oc) =>
-      oc
-        .columns(['token', 'owner'])
-        .doUpdateSet({ ...data, updatedAt: new Date().toISOString() })
-    )
-    .execute()
+    const data: Insertable<Tables['balances']> = {
+      token: token.id,
+      owner: job.data.owner.id,
+      balance,
+      ethValue: balance * rateToEth,
+    }
+
+    await db
+      .insertInto('balances')
+      .values(data)
+      .onConflict((oc) =>
+        oc
+          .columns(['token', 'owner'])
+          .doUpdateSet({ ...data, updatedAt: new Date().toISOString() })
+      )
+      .execute()
+  }
 }