1 files changed, 63 insertions, 1 deletions
diff --git a/src/0x.js.ts b/src/0x.js.ts
index de082146f..aed7513a8 100644
--- a/src/0x.js.ts
+++ b/src/0x.js.ts
@@ -8,9 +8,11 @@ import {Web3Wrapper} from './web3_wrapper';
 import {constants} from './utils/constants';
 import {utils} from './utils/utils';
 import {assert} from './utils/assert';
+import findVersions = require('find-versions');
+import compareVersions = require('compare-versions');
 import {ExchangeWrapper} from './contract_wrappers/exchange_wrapper';
 import {ECSignatureSchema} from './schemas/ec_signature_schema';
-import {SolidityTypes, ECSignature} from './types';
+import {SolidityTypes, ECSignature, ZeroExError} from './types';
 
 const MAX_DIGITS_IN_UNSIGNED_256_INT = 78;
 
@@ -131,4 +133,64 @@ export class ZeroEx {
         this.web3Wrapper = new Web3Wrapper(web3);
         this.exchange = new ExchangeWrapper(this.web3Wrapper);
     }
+    /**
+     * Signs an orderHash and returns it's elliptic curve signature
+     * This method currently supports TestRPC, Geth and Parity above and below V1.6.6
+     */
+    public async signOrderHashAsync(orderHashHex: string): Promise<ECSignature> {
+        assert.isHexString('orderHashHex', orderHashHex);
+
+        let msgHashHex;
+        const nodeVersion = await this.web3Wrapper.getNodeVersionAsync();
+        const isParityNode = utils.isParityNode(nodeVersion);
+        if (isParityNode) {
+            // Parity node adds the personalMessage prefix itself
+            msgHashHex = orderHashHex;
+        } else {
+            const orderHashBuff = ethUtil.toBuffer(orderHashHex);
+            const msgHashBuff = ethUtil.hashPersonalMessage(orderHashBuff);
+            msgHashHex = ethUtil.bufferToHex(msgHashBuff);
+        }
+
+        const makerAddressIfExists = await this.web3Wrapper.getSenderAddressIfExistsAsync();
+        if (_.isUndefined(makerAddressIfExists)) {
+            throw new Error(ZeroExError.USER_HAS_NO_ASSOCIATED_ADDRESSES);
+        }
+
+        const signature = await this.web3Wrapper.signTransactionAsync(makerAddressIfExists, msgHashHex);
+
+        let signatureData;
+        const [nodeVersionNumber] = findVersions(nodeVersion);
+        // Parity v1.6.6 and earlier returns the signatureData as vrs instead of rsv as Geth does
+        // Later versions return rsv but for the time being we still want to support version < 1.6.6
+        // Date: May 23rd 2017
+        const latestParityVersionWithVRS = '1.6.6';
+        const isVersionBeforeParityFix = compareVersions(nodeVersionNumber, latestParityVersionWithVRS) <= 0;
+        if (isParityNode && isVersionBeforeParityFix) {
+            const signatureBuffer = ethUtil.toBuffer(signature);
+            let v = signatureBuffer[0];
+            if (v < 27) {
+                v += 27;
+            }
+            signatureData = {
+                v,
+                r: signatureBuffer.slice(1, 33),
+                s: signatureBuffer.slice(33, 65),
+            };
+        } else {
+            signatureData = ethUtil.fromRpcSig(signature);
+        }
+
+        const {v, r, s} = signatureData;
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        const isValidSignature = ZeroEx.isValidSignature(orderHashHex, ecSignature, makerAddressIfExists);
+        if (!isValidSignature) {
+            throw new Error(ZeroExError.INVALID_SIGNATURE);
+        }
+        return ecSignature;
+    }
 }