sha3 method signature

2 files changed, 18 insertions, 4 deletions

diff --git a/lib/abi.js b/lib/abi.js
index 5a4d64515..80cc0d551 100644
--- a/lib/abi.js
+++ b/lib/abi.js
@@ -140,7 +140,6 @@ var toAbiInput = function (json, methodName, params) {
         return;
     }
 
-    bytes = "0x" + padLeft(index.toString(16), 2);
     var method = json[index];
 
     for (var i = 0; i < method.inputs.length; i++) {
@@ -259,7 +258,20 @@ var outputParser = function (json) {
     return parser;
 };
 
+var methodSignature = function (json, name) {
+    var method = json[findMethodIndex(json, name)];
+    var result = name + '(';
+    var inputTypes = method.inputs.map(function (inp) {
+        return inp.type;
+    });
+    result += inputTypes.join(',');
+    result += ')';
+
+    return web3.sha3(result);
+};
+
 module.exports = {
     inputParser: inputParser,
-    outputParser: outputParser
+    outputParser: outputParser,
+    methodSignature: methodSignature
 };
diff --git a/lib/contract.js b/lib/contract.js
index b10339003..1a03849bf 100644
--- a/lib/contract.js
+++ b/lib/contract.js
@@ -46,8 +46,10 @@ var contract = function (address, desc) {
                 call: function (extra) {
                     extra = extra || {};
                     extra.to = address;
-                    extra.data = parsed;
-                    return web3.eth.call(extra).then(onSuccess);
+                    return abi.methodSignature(desc, method.name).then(function (signature) {
+                        extra.data = signature.slice(0, 10) + parsed;
+                        return web3.eth.call(extra).then(onSuccess);
+                    });
                 },
                 transact: function (extra) {
                     extra = extra || {};