feat: allow to switch on direct transaction when the relayer service …

…is down (#865)

packages/core-sdk/src/meta-tx/biconomy.ts

@@ -189,4 +189,30 @@ export class Biconomy {
     }
     return resubmittedResponse;
   }
+
+  public async check(
+    args: {
+      contract?: string;
+    } = {}
+  ): Promise<boolean> {
+    const url = `${
+      this._relayerUrl
+    }/ready?apiKey=${this._apiKey || ""}&apiId=${this._apiId || ""}&contract=${args.contract || ""}`;
+    try {
+      const response = await _fetch(url, {
+        method: "GET",
+        headers: {
+          "content-type": "application/json;charset=UTF-8",
+          "Access-Control-Allow-Origin": "*"
+        }
+      });
+      if (!response.ok) {
+        return false;
+      }
+      const json = (await response.json()) as { ready: boolean };
+      return json?.ready || false;
+    } catch (e) {
+      return false;
+    }
+  }
 }

packages/core-sdk/src/mixins/base-core-sdk.ts

@@ -7,6 +7,7 @@ import {
   ErrorFragment
 } from "@bosonprotocol/common";
 import { TokenInfoManager } from "../utils/tokenInfoManager";
+import { Biconomy } from "../meta-tx/biconomy";
 
 export class BaseCoreSDK {
   protected _web3Lib: Web3LibAdapter;
@@ -91,6 +92,28 @@ export class BaseCoreSDK {
       contractAddress
     };
   }
+
+  protected async assertAndGetMetaTxConfig2(
+    overrides: Partial<{
+      verifierAddress: string;
+      metaTxConfig: Partial<Omit<MetaTxConfig, "apiIds"> & { apiId: string }>;
+      metaTransactionMethod: string;
+    }> = {}
+  ) {
+    const ret = this.assertAndGetMetaTxConfig(overrides);
+
+    // Check the meta-tx gateway is ready and accepts relaying transaction to the targeted contract
+    const biconomy = new Biconomy(
+      ret.metaTxRelayerUrl,
+      ret.metaTxApiKey,
+      ret.metaTxApiId
+    );
+    const ready = await biconomy.check({
+      contract: ret.contractAddress
+    });
+
+    return ready ? ret : undefined;
+  }
 }
 
 // Doc: https://www.typescriptlang.org/docs/handbook/mixins.html#alternative-pattern