feat: add support for custom fetcher on Provider (FuelLabs#767)

.changeset/shiny-experts-flow.md

@@ -0,0 +1,5 @@
+---
+"@fuel-ts/providers": minor
+---
+
+`Provider` can now accept options for additional network-related configurations.

packages/providers/src/provider.test.ts

@@ -5,9 +5,15 @@ import { bn } from '@fuel-ts/math';
 import type { Receipt } from '@fuel-ts/transactions';
 import { ReceiptType, TransactionType } from '@fuel-ts/transactions';
 import * as GraphQL from 'graphql-request';
+// eslint-disable-next-line import/no-extraneous-dependencies
+import fetch, { Response } from 'node-fetch';
 
 import Provider from './provider';
 
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
 describe('Provider', () => {
   it('can getVersion()', async () => {
     const provider = new Provider('http://127.0.0.1:4000/graphql');
@@ -154,7 +160,7 @@ describe('Provider', () => {
     expect(minGasPrice).toBeDefined();
   });
 
-  it('can change the provider url of the curernt instance', async () => {
+  it('can change the provider url of the current instance', async () => {
     const providerUrl1 = 'http://127.0.0.1:4000/graphql';
     const providerUrl2 = 'http://127.0.0.1:8080/graphql';
     const provider = new Provider(providerUrl1);
@@ -163,6 +169,34 @@ describe('Provider', () => {
     expect(provider.url).toBe(providerUrl1);
     provider.connect(providerUrl2);
     expect(provider.url).toBe(providerUrl2);
-    expect(spyGraphQLClient).toBeCalledWith(providerUrl2);
+    expect(spyGraphQLClient).toBeCalledWith(providerUrl2, undefined);
+  });
+
+  it('can accept a custom fetch function', async () => {
+    const providerUrl = 'http://127.0.0.1:4000/graphql';
+
+    const customFetch = async (
+      url: string,
+      options: {
+        body: string;
+        headers: { [key: string]: string };
+        [key: string]: unknown;
+      }
+    ) => {
+      const graphqlRequest = JSON.parse(options.body);
+      const { operationName } = graphqlRequest;
+      if (operationName === 'getVersion') {
+        const responseText = JSON.stringify({
+          data: { nodeInfo: { nodeVersion: '0.30.0' } },
+        });
+        const response = new Response(responseText, options);
+
+        return response;
+      }
+      return fetch(url, options);
+    };
+
+    const provider = new Provider(providerUrl, { fetch: customFetch });
+    expect(await provider.getVersion()).toEqual('0.30.0');
   });
 });

packages/providers/src/provider.ts

@@ -190,6 +190,19 @@ export type BuildPredicateOptions = {
   fundTransaction?: boolean;
 } & Pick<TransactionRequestLike, 'gasLimit' | 'gasPrice' | 'maturity'>;
 
+export type FetchRequestOptions = {
+  method: 'POST';
+  headers: { [key: string]: string };
+  body: string;
+};
+
+/*
+ * Provider initialization options
+ */
+export type ProviderOptions = {
+  fetch?: (url: string, options: FetchRequestOptions) => Promise<any>;
+};
+
 /**
  * Provider Call transaction params
  */
@@ -204,17 +217,18 @@ export default class Provider {
 
   constructor(
     /** GraphQL endpoint of the Fuel node */
-    public url: string
+    public url: string,
+    public options: ProviderOptions = {}
   ) {
-    this.operations = this.createOperations(url);
+    this.operations = this.createOperations(url, options);
   }
 
   /**
    * Create GraphQL client and set operations
    */
-  private createOperations(url: string) {
+  private createOperations(url: string, options: ProviderOptions = {}) {
     this.url = url;
-    const gqlClient = new GraphQLClient(url);
+    const gqlClient = new GraphQLClient(url, options.fetch ? { fetch: options.fetch } : undefined);
     return getOperationsSdk(gqlClient);
   }