✨ Fallthrough RPC provider (#90)

* setup static class exporting for provider prep

* ignore from docusaurus

* scaffold the fallthrough provider - needs tests

* broken

* partial progress

* step zero

* implement basic fallthrough behavior

* timeout post at 8 seconds

* reduce long string hex bloat

* Customize timeout duration

* mutex the current rpc url selection

* speed up husky update scripts

* document fallthroughprovider

* cleanup docs

* Move all jsonrpc to shared base provider

* polyfill performance

package.json

@@ -32,7 +32,6 @@
     "prepublishOnly": "npm run build"
   },
   "devDependencies": {
-    "@ethersproject/keccak256": "^5.4.0",
     "@types/body-parser": "^1.19.1",
     "@types/eslint": "^8.4.1",
     "@types/express": "^4.17.13",
@@ -52,8 +51,9 @@
     "jest": "^27.5.1",
     "jest-dev-server": "^6.0.3",
     "just-omit": "^2.0.1",
-    "lint-staged": "^12.4.0",
+    "lint-staged": "^12.4.1",
     "npm-run-all": "^4.1.5",
+    "perf_hooks": "^0.0.1",
     "prettier": "^2.6.2",
     "prettier-plugin-organize-imports": "^2.3.4",
     "ts-jest": "^27.1.4",

readme.md

@@ -255,10 +255,31 @@ import { JsonRpcProvider } from 'essential-eth';
 const essentialEth = new JsonRpcProvider(
   'RPC URL HERE' /* Try POKT or Infura */,
 );
-// OR for very quick testing (limited to 500 requests)
+// OR for very quick testing (limited to 10,000 requests)
 const essentialEth = new JsonRpcProvider();
 ```
 
+<details>
+  <summary>Want a redundant provider that handles outages?</summary>
+
+```typescript
+import { FallthroughProvider } from 'essential-eth';
+
+// The FallthroughProvider handles falling through to the next valid URL.
+// It's dynamic to never trust one URL again when it fails * until it has tried all other provided URLs
+// The default timeout for a request is 8 seconds after which it moves to the next URL
+const provider = new FallthroughProvider([
+  'https://bad.com',
+  'https://free-eth-node.com/api/eth',
+]);
+provider.getGasPrice().toNumber();
+/*
+39695942769
+*/
+```
+
+</details>
+
  <br/>
 
 #### [`getTransactionCount(address, blockTag?): Promise<number>`](https://essential-eth.vercel.app/docs/api/classes/JsonRpcProvider#gettransactioncount)

scripts/pre-commit.sh

@@ -1,4 +1,4 @@
-npx npm-check-updates -u  "/.*lint.*$/"
+npx npm-check-updates -u  "/.*eslint.*$/"
 npx npm-check-updates -u  "/.*big.*$/"
 npm i
 npm i ethers@latest typescript@latest web3@latest prettier@latest

src/classes/Contract.ts

@@ -66,7 +66,7 @@ export class BaseContract {
                   : null;
               const req = async (): Promise<string> => {
                 return await post(
-                  this._provider._rpcUrl,
+                  this._provider.selectRpcUrl(),
                   buildRPCPostBody('eth_call', [
                     {
                       to: this._address.toLowerCase(),
@@ -101,8 +101,9 @@ export function defineReadOnly<T>(object: T, name: string, value: any): void {
 }
 
 /**
+ * @alpha
  * Only accepts ABIS in JSON format. This allows for stronger typing and assurances of data-types
- * @alpha Only read-only function calls supported.
+ * * Only read-only function calls currently supported.
  * @example
  * ```typescript
  * import { Contract, JsonRpcProvider } from 'essential-eth';

src/classes/test/Contract/crv.test.ts

@@ -1,7 +1,7 @@
 import { Contract as EthersContract } from '@ethersproject/contracts';
 import { StaticJsonRpcProvider } from '@ethersproject/providers';
 import { TinyBig } from '../../..';
-import { JsonRpcProvider } from '../../../providers/JsonRpcProvider';
+import { JsonRpcProvider } from '../../../index';
 import { rpcUrls } from '../../../providers/test/rpc-urls';
 import { Contract as EssentialEthContract } from '../../Contract';
 import { abi } from './crv-abi';

src/classes/test/Contract/ens.test.ts

@@ -1,6 +1,6 @@
 import { Contract as EthersContract } from '@ethersproject/contracts';
 import { StaticJsonRpcProvider } from '@ethersproject/providers';
-import { JsonRpcProvider } from '../../../providers/JsonRpcProvider';
+import { JsonRpcProvider } from '../../../index';
 import { Contract as EssentialEthContract } from '../../Contract';
 import { rpcUrls } from './../../../providers/test/rpc-urls';
 import { ensABI } from './ens-abi';

src/classes/test/Contract/fei.test.ts

@@ -1,7 +1,7 @@
 import { Contract as EthersContract } from '@ethersproject/contracts';
 import { StaticJsonRpcProvider } from '@ethersproject/providers';
 import { TinyBig } from '../../..';
-import { JsonRpcProvider } from '../../../providers/JsonRpcProvider';
+import { JsonRpcProvider } from '../../../index';
 import { Contract as EssentialEthContract } from '../../Contract';
 import { rpcUrls } from './../../../providers/test/rpc-urls';
 import { feiABI } from './fei-abi';

src/classes/test/Contract/uni.test.ts

@@ -1,6 +1,6 @@
 import { Contract as EthersContract } from '@ethersproject/contracts';
 import { StaticJsonRpcProvider } from '@ethersproject/providers';
-import { JsonRpcProvider } from '../../../providers/JsonRpcProvider';
+import { JsonRpcProvider } from '../../../index';
 import { Contract as EssentialEthContract } from '../../Contract';
 import { rpcUrls } from './../../../providers/test/rpc-urls';
 import { uniswapABI } from './uniswap-abi';

src/classes/utils/encode-decode-transaction.ts

@@ -3,10 +3,8 @@ import { tinyBig, toChecksumAddress } from '../..';
 import { ContractTypes, JSONABIArgument } from '../../types/Contract.types';
 import { hexToDecimal } from './hex-to-decimal';
 
-const hexTrue =
-  '0000000000000000000000000000000000000000000000000000000000000001';
-const hexFalse =
-  '0000000000000000000000000000000000000000000000000000000000000000';
+export const hexFalse = '0'.repeat(64);
+const hexTrue = '0'.repeat(63) + '1';
 
 function expandType(type: ContractTypes) {
   // https://docs.soliditylang.org/en/v0.8.7/types.html#integers

src/index.ts

@@ -1,4 +1,5 @@
 import { Contract } from './classes/Contract';
+import { FallthroughProvider } from './providers/FallthroughProvider';
 import { JsonRpcProvider, jsonRpcProvider } from './providers/JsonRpcProvider';
 import { tinyBig, TinyBig } from './shared/tiny-big/tiny-big';
 import { BlockResponse } from './types/Block.types';
@@ -24,6 +25,7 @@ export {
   isAddress,
   jsonRpcProvider,
   JsonRpcProvider,
+  FallthroughProvider,
   tinyBig,
   toChecksumAddress,
   weiToEther,