Throw and handle errors from Providers.

In web3 wrapper when a response contains an error field we throw this rather than return response.result which is often undefined.
In Signature Utils we handle the error thrown when a user rejects the signing dialogue to prevent double signing.
Exposed the ZeroExTransaction JSON schema.
In Website only use the MetamaskSubprovider if we can detect the provider is Metamask

3 files changed, 32 insertions, 2 deletions

diff --git a/packages/web3-wrapper/CHANGELOG.json b/packages/web3-wrapper/CHANGELOG.json
index 47f054300..be5c1fef6 100644
--- a/packages/web3-wrapper/CHANGELOG.json
+++ b/packages/web3-wrapper/CHANGELOG.json
@@ -1,5 +1,19 @@
 [
     {
+        "version": "3.1.0",
+        "changes": [
+            {
+                "note": "Add `signTypedData` to perform EIP712 `eth_signTypedData`.",
+                "pr": 1102
+            },
+            {
+                "note":
+                    "Web3Wrapper now throws when an RPC request contains an error field in the response. Previously errors could be swallowed and undefined returned.",
+                "pr": 1102
+            }
+        ]
+    },
+    {
         "version": "3.0.3",
         "changes": [
             {
diff --git a/packages/web3-wrapper/src/web3_wrapper.ts b/packages/web3-wrapper/src/web3_wrapper.ts
index 034bafb5f..726246f1a 100644
--- a/packages/web3-wrapper/src/web3_wrapper.ts
+++ b/packages/web3-wrapper/src/web3_wrapper.ts
@@ -322,7 +322,7 @@ export class Web3Wrapper {
      */
     public async signTypedDataAsync(address: string, typedData: any): Promise<string> {
         assert.isETHAddressHex('address', address);
-        assert.doesConformToSchema('typedData', typedData, schemas.eip712TypedData);
+        assert.doesConformToSchema('typedData', typedData, schemas.eip712TypedDataSchema);
         const signData = await this.sendRawPayloadAsync<string>({
             method: 'eth_signTypedData',
             params: [address, typedData],
@@ -669,6 +669,9 @@ export class Web3Wrapper {
             ...payload,
         };
         const response = await promisify<JSONRPCResponsePayload>(sendAsync)(payloadWithDefaults);
+        if (response.error) {
+            throw new Error(response.error.message);
+        }
         const result = response.result;
         return result;
     }
diff --git a/packages/web3-wrapper/test/web3_wrapper_test.ts b/packages/web3-wrapper/test/web3_wrapper_test.ts
index 385c469bf..164253777 100644
--- a/packages/web3-wrapper/test/web3_wrapper_test.ts
+++ b/packages/web3-wrapper/test/web3_wrapper_test.ts
@@ -1,5 +1,5 @@
 import * as chai from 'chai';
-import { BlockParamLiteral } from 'ethereum-types';
+import { BlockParamLiteral, JSONRPCErrorCallback, JSONRPCRequestPayload } from 'ethereum-types';
 import * as Ganache from 'ganache-core';
 import * as _ from 'lodash';
 import 'mocha';
@@ -78,6 +78,19 @@ describe('Web3Wrapper tests', () => {
             const signatureLength = 132;
             expect(signature.length).to.be.equal(signatureLength);
         });
+        it('should throw if the provider returns an error', async () => {
+            const message = '0xdeadbeef';
+            const signer = addresses[1];
+            const fakeProvider = {
+                async sendAsync(payload: JSONRPCRequestPayload, callback: JSONRPCErrorCallback): Promise<void> {
+                    callback(new Error('User denied message signature'));
+                },
+            };
+            const errorWeb3Wrapper = new Web3Wrapper(fakeProvider);
+            expect(errorWeb3Wrapper.signMessageAsync(signer, message)).to.be.rejectedWith(
+                'User denied message signature',
+            );
+        });
     });
     describe('#getBlockNumberAsync', () => {
         it('get block number', async () => {