1 files changed, 74 insertions, 0 deletions
diff --git a/packages/subproviders/src/subproviders/signer.ts b/packages/subproviders/src/subproviders/signer.ts
new file mode 100644
index 000000000..08a9daceb
--- /dev/null
+++ b/packages/subproviders/src/subproviders/signer.ts
@@ -0,0 +1,74 @@
+import { Web3Wrapper } from '@0xproject/web3-wrapper';
+import { JSONRPCRequestPayload, Provider } from 'ethereum-types';
+
+import { Callback, ErrorCallback } from '../types';
+
+import { Subprovider } from './subprovider';
+
+/**
+ * This class implements the [web3-provider-engine](https://github.com/MetaMask/provider-engine)
+ * subprovider interface. It forwards JSON RPC requests involving the domain of a signer (getAccounts,
+ * sendTransaction, signMessage etc...) to the provider instance supplied at instantiation. All other requests
+ * are passed onwards for subsequent subproviders to handle.
+ */
+export class SignerSubprovider extends Subprovider {
+    private _web3Wrapper: Web3Wrapper;
+    /**
+     * Instantiates a new SignerSubprovider
+     * @param provider Web3 provider that should handle  all user account related requests
+     */
+    constructor(provider: Provider) {
+        super();
+        this._web3Wrapper = new Web3Wrapper(provider);
+    }
+    /**
+     * This method conforms to the web3-provider-engine interface.
+     * It is called internally by the ProviderEngine when it is this subproviders
+     * turn to handle a JSON RPC request.
+     * @param payload JSON RPC payload
+     * @param next Callback to call if this subprovider decides not to handle the request
+     * @param end Callback to call if subprovider handled the request and wants to pass back the request.
+     */
+    // tslint:disable-next-line:prefer-function-over-method async-suffix
+    public async handleRequest(payload: JSONRPCRequestPayload, next: Callback, end: ErrorCallback): Promise<void> {
+        switch (payload.method) {
+            case 'web3_clientVersion':
+                try {
+                    const nodeVersion = await this._web3Wrapper.getNodeVersionAsync();
+                    end(null, nodeVersion);
+                } catch (err) {
+                    end(err);
+                }
+                return;
+            case 'eth_accounts':
+                try {
+                    const accounts = await this._web3Wrapper.getAvailableAddressesAsync();
+                    end(null, accounts);
+                } catch (err) {
+                    end(err);
+                }
+                return;
+            case 'eth_sendTransaction':
+                const [txParams] = payload.params;
+                try {
+                    const txHash = await this._web3Wrapper.sendTransactionAsync(txParams);
+                    end(null, txHash);
+                } catch (err) {
+                    end(err);
+                }
+                return;
+            case 'eth_sign':
+                const [address, message] = payload.params;
+                try {
+                    const signature = await this._web3Wrapper.signMessageAsync(address, message);
+                    end(null, signature);
+                } catch (err) {
+                    end(err);
+                }
+                return;
+            default:
+                next();
+                return;
+        }
+    }
+}