Utility function to decode arbitrary 0x calldata

packages/utils/package.json

@@ -14,7 +14,7 @@
         "lint": "tslint --format stylish --project .",
         "test": "yarn run_mocha",
         "test:circleci": "yarn test:coverage",
-        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe lib/test/**/*_test.js --bail --exit",
+        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*_test.js' 'lib/test/*_test.js'  --bail --exit",
         "test:coverage": "nyc npm run test --all && yarn coverage:report:lcov",
         "coverage:report:lcov": "nyc report --reporter=text-lcov > coverage/lcov.info"
     },

packages/utils/src/calldata_decoder.ts

@@ -0,0 +1,66 @@
+// Decodes any 0x transaction
+
+import * as ContractArtifacts from '@0x/contract-artifacts';
+import { SimpleContractArtifact } from '@0x/types';
+import { ContractAbi, MethodAbi } from 'ethereum-types';
+import * as _ from 'lodash';
+import { AbiEncoder } from '.';
+
+export interface DecodedCalldata {
+    functionName: string;
+    functionSignature: string;
+    functionArguments: any;
+}
+
+interface AbiEncoderBySelector {
+    [index: string]: AbiEncoder.Method;
+}
+
+export class CalldataDecoder {
+    private readonly _abiEncoderBySelector: AbiEncoderBySelector = {};
+    private static _instance: CalldataDecoder;
+
+    public static getInstance(): CalldataDecoder {
+        if (!CalldataDecoder._instance) {
+            CalldataDecoder._instance = new CalldataDecoder();
+        }
+        return CalldataDecoder._instance;
+    }
+
+    public constructor() {
+        _.each(ContractArtifacts, (contractArtifactAsJson: any) => {
+            const conractArtifact = contractArtifactAsJson as SimpleContractArtifact;
+            const contractAbi: ContractAbi = conractArtifact.compilerOutput.abi;
+            const functionAbis = _.filter(contractAbi, (abiEntry) => {return abiEntry.type === 'function'}) as MethodAbi[];
+            _.each(functionAbis, (functionAbi) => {
+                const abiEncoder = new AbiEncoder.Method(functionAbi);
+                const functionSelector = abiEncoder.getSelector();
+                if (_.has(this._abiEncoderBySelector, functionSelector)) {
+                    return;
+                }
+                this._abiEncoderBySelector[functionSelector] = abiEncoder;
+            });
+        });
+    }
+
+    public static decode(calldata: string, rules?: AbiEncoder.DecodingRules): DecodedCalldata {
+        if (!calldata.startsWith('0x') || calldata.length < 10) {
+            throw new Error(`Malformed calldata. Must include hex prefix '0x' and 4-byte function selector. Got '${calldata}'`);
+        }
+        const functionSelector = calldata.substr(0, 10);
+        const instance = CalldataDecoder.getInstance();
+        const abiEncoder = instance._abiEncoderBySelector[functionSelector];
+        if (_.isUndefined(abiEncoder)) {
+            throw new Error(`Could not find matching abi encoder for selector '${functionSelector}'`);
+        }
+        const functionName = abiEncoder.getDataItem().name;
+        const functionSignature = abiEncoder.getSignatureType();
+        const functionArguments = abiEncoder.decode(calldata, rules);
+        const decodedCalldata = {
+            functionName,
+            functionSignature,
+            functionArguments
+        }
+        return decodedCalldata;
+    }
+}

packages/utils/src/index.ts

@@ -11,3 +11,4 @@ export { errorUtils } from './error_utils';
 export { fetchAsync } from './fetch_async';
 export { signTypedDataUtils } from './sign_typed_data_utils';
 export import AbiEncoder = require('./abi_encoder');
+export { CalldataDecoder } from './calldata_decoder';

packages/utils/test/calldata_decoder_test.ts

@@ -0,0 +1,21 @@
+import * as chai from 'chai';
+import 'mocha';
+
+import { CalldataDecoder } from '../src';
+import { chaiSetup } from './utils/chai_setup';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe.only('CalldataDecoder', () => {
+    describe.only('decodeCalldata', () => {
+        it.only('should successfull decode fillOrder calldata', async () => {
+            //const cancelCalldata = '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';
+            //const marketBuycalldata = '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';
+            const calldata = '0x3c28d861000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000002c000000000000000000000000000000000000000000000000000000000000004800000000000000000000000000000000000000000000000000000000000000500000000000000000000000000da912ecc847b3d98ca882e396e693e485deed5180000000000000000000000000681e844593a051e2882ec897ecd5444efe19ff20000000000000000000000008124071f810d533ff63de61d0c98db99eeb99d640000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000008bb6a7394e2f000000000000000000000000000000000000000000000000868cab59cce788000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005c51035008197e43b4d84439ec534b62670eaaaf4a46f50ff37ff62f6d1c1fbe8b036d3c000000000000000000000000000000000000000000000000000000000000018000000000000000000000000000000000000000000000000000000000000001e00000000000000000000000000000000000000000000000000000000000000024f47261b0000000000000000000000000c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000024f47261b0000000000000000000000000503f9794d6a6bb0df8fbb19a2b3e2aeab35339ad000000000000000000000000000000000000000000000000000000000000000000000000000000003997d0f55d1daa549e95c240bc6353636f4cf9740000000000000000000000000681e844593a051e2882ec897ecd5444efe19ff20000000000000000000000008124071f810d533ff63de61d0c98db99eeb99d6400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000871bcc4c32c9d66800000000000000000000000000000000000000000000000000008a70a4d2d2100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005c510350c20e53540c9b2c9207ad9a04e472e2224af211f08efc2f0eec15d7e1cfbf2109000000000000000000000000000000000000000000000000000000000000018000000000000000000000000000000000000000000000000000000000000001a00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000421c8f294b2728c269a9d01a1b58fe7cae2ef7895bd2de48cc3101eb47464d96594340924793fc8325db26a3abd5602605806a82ca77e810494c5ecab58b03449de80300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000421c372d6daa8e6ce2c696e51b6e1e33f10fd2b41b403cd88c311a617c3656ea02fe454e51cddf4682751bea9a02ce725cf364d1107f27be427d5157adbdcca2609b03000000000000000000000000000000000000000000000000000000000000';
+            const decodedCalldata = CalldataDecoder.decode(calldata);
+            console.log(JSON.stringify(decodedCalldata, null, 4));
+            expect(5).to.be.equal(5);
+        });
+    });
+});