Introduce FailoverRpcProvider that switches between providers in case of a failure of one of them

.changeset/shiny-coats-fly.md

@@ -0,0 +1,7 @@
+---
+"@near-js/accounts": minor
+"@near-js/providers": minor
+"@near-js/wallet-account": minor
+---
+
+Introduce FailoverRpcProvider that switches between providers in case of a failure of one of them

packages/accounts/src/connection.ts

@@ -1,5 +1,5 @@
 import { Signer, InMemorySigner } from '@near-js/signers';
-import { Provider, JsonRpcProvider } from '@near-js/providers';
+import { Provider, JsonRpcProvider, FailoverRpcProvider } from '@near-js/providers';
 import { IntoConnection } from './interface';
 
 /**
@@ -11,6 +11,10 @@ function getProvider(config: any): Provider {
         case undefined:
             return config;
         case 'JsonRpcProvider': return new JsonRpcProvider({ ...config.args });
+        case 'FailoverRpcProvider': {
+            const providers = (config?.args || []).map((arg) => new JsonRpcProvider(arg));
+            return new FailoverRpcProvider(providers);
+        }
         default: throw new Error(`Unknown provider type ${config.type}`);
     }
 }

packages/cookbook/api-keys/backup-provider.js

@@ -0,0 +1,27 @@
+// demonstrates how to use multiple providers with different API-KEYs
+const { providers } = require('near-api-js');
+
+const RPC_API_ENDPOINT_1 = '<Replace this string with your RPC server URL>';
+const API_KEY_1 = '<Replace this string with your API KEY>';
+
+const RPC_API_ENDPOINT_2 = '<Replace this string with another RPC server URL>';
+const API_KEY_2 = '<Replace this string with another API KEY>';
+
+const jsonProviders = [
+    new providers.JsonRpcProvider({
+        url: RPC_API_ENDPOINT_1,
+        headers: { 'x-api-key': API_KEY_1 },
+    }),
+    new providers.JsonRpcProvider({
+        url: RPC_API_ENDPOINT_2,
+        headers: { 'x-api-key': API_KEY_2 },
+    }),
+];
+const provider = new providers.FailoverRpcProvider(jsonProviders);
+
+getNetworkStatus();
+
+async function getNetworkStatus() {
+    const result = await provider.status();
+    console.log(result);
+}

packages/near-api-js/src/providers/failover-rpc-provider.ts

@@ -0,0 +1 @@
+export { FailoverRpcProvider } from '@near-js/providers';

packages/near-api-js/src/providers/index.ts

@@ -2,11 +2,13 @@
 
 import { Provider, FinalExecutionOutcome, ExecutionOutcomeWithId, getTransactionLastResult, FinalExecutionStatus, FinalExecutionStatusBasic } from './provider';
 import { JsonRpcProvider, TypedError, ErrorContext } from './json-rpc-provider';
+import { FailoverRpcProvider } from './failover-rpc-provider';
 
 export {
     Provider,
     FinalExecutionOutcome,
     JsonRpcProvider,
+    FailoverRpcProvider,
     ExecutionOutcomeWithId,
     FinalExecutionStatus,
     FinalExecutionStatusBasic,