feat: Implement addtional fee estimation via resolvers

package.json

@@ -42,7 +42,8 @@
     "pg": "^8.11.3",
     "pino": "^8.15.1",
     "reflect-metadata": "^0.1.13",
-    "rxjs": "^7.8.1"
+    "rxjs": "^7.8.1",
+    "viem": "^2.15.1"
   },
   "devDependencies": {
     "@nestjs/cli": "^10.0.0",

src/resolvers/base-sepolia.ts

@@ -0,0 +1,24 @@
+import pino from "pino";
+import { JsonRpcProvider } from "ethers6";
+import { ResolverConfig } from "./resolver";
+import OPStackResolver from "./op-stack";
+
+export const BASE_SEPOLIA_CHAIN_NAME = 'baseSepolia';
+
+export class BaseSepoliaResolver extends OPStackResolver {
+
+    constructor(
+        config: ResolverConfig,
+        provider: JsonRpcProvider,
+        logger: pino.Logger,
+    ) {
+        super(
+            BASE_SEPOLIA_CHAIN_NAME,
+            config,
+            provider,
+            logger,
+        );
+    }
+}
+
+export default BaseSepoliaResolver;

src/resolvers/op-stack.ts

@@ -0,0 +1,54 @@
+import { JsonRpcProvider, TransactionRequest } from "ethers6";
+import { Resolver, ResolverConfig } from "./resolver";
+import pino from "pino";
+import { createPublicClient, http } from "viem";
+import { publicActionsL2 } from 'viem/op-stack'
+
+export const RESOLVER_TYPE_OP_STACK = 'op-stack';
+
+export class OPStackResolver extends Resolver {
+    override readonly resolverType;
+
+    private client: any;    //TODO use VIEM types
+
+    constructor(
+        chainName: string,
+        config: ResolverConfig,
+        provider: JsonRpcProvider,
+        logger: pino.Logger,
+    ) {
+        super(
+            config,
+            provider,
+            logger,
+        );
+
+        this.resolverType = RESOLVER_TYPE_OP_STACK;
+
+        this.client = this.loadClient(
+            chainName,
+            this.provider._getConnection().url  //TODO the 'rpc' url should be added to the ResolverConfig
+        );
+    }
+
+    private loadClient(
+        chainName: string,
+        rpc: string,
+    ): any {
+        // eslint-disable-next-line @typescript-eslint/no-var-requires
+        const chain = require(`viem/chains`)[chainName];
+
+        return createPublicClient({
+            chain,
+            transport: http(rpc),
+        }).extend(publicActionsL2());
+    }
+
+    override async estimateAdditionalFee(
+        transactionRequest: TransactionRequest
+    ): Promise<bigint> {
+        return this.client.estimateL1Fee(transactionRequest)
+    }
+}
+
+export default OPStackResolver;

src/resolvers/optimism-sepolia.ts

@@ -0,0 +1,24 @@
+import pino from "pino";
+import { JsonRpcProvider } from "ethers6";
+import { ResolverConfig } from "./resolver";
+import OPStackResolver from "./op-stack";
+
+export const OPTIMISM_SEPOLIA_CHAIN_NAME = 'optimismSepolia';
+
+export class OptimismSepoliaResolver extends OPStackResolver {
+
+    constructor(
+        config: ResolverConfig,
+        provider: JsonRpcProvider,
+        logger: pino.Logger,
+    ) {
+        super(
+            OPTIMISM_SEPOLIA_CHAIN_NAME,
+            config,
+            provider,
+            logger,
+        );
+    }
+}
+
+export default OptimismSepoliaResolver;

src/resolvers/resolver.ts

@@ -1,4 +1,4 @@
-import { JsonRpcProvider } from "ethers6";
+import { JsonRpcProvider, TransactionRequest } from "ethers6";
 import pino from "pino";
 
 export const RESOLVER_TYPE_DEFAULT = 'default';
@@ -78,4 +78,10 @@ export class Resolver {
     ): Promise<number> {
         return new Promise((resolve) => resolve(observedBlockNumber));
     };
+
+    estimateAdditionalFee(
+        _transactionRequest: TransactionRequest
+    ): Promise<bigint> {
+        return new Promise((resolve) => resolve(0n));
+    }
 }