add rpc call batching

Readme.md

@@ -64,3 +64,19 @@ client.cmd('getbalance', '*', 6, function(err, balance){
   console.log('Balance:', balance);
 });
 ```
+
+### Batch multiple RPC calls into single HTTP request
+
+```js
+var batch = [];
+for (var i = 0; i < 10; ++i) {
+  batch.push({
+    method: 'getnewaddress',
+    params: ['myaccount']
+  });
+}
+client.cmd(batch, function(err, address) {
+  if (err) return console.log(err);
+  console.log('Address:', address);
+});
+```

lib/jsonrpc.js

@@ -14,13 +14,31 @@ var Client = function(port, host, user, password) {
   this.password = password;
 
   this.call = function(method, params, callback, errback, path) {
+    
+    var time = Date.now();
+    var requestJSON;
+    
+    if (Array.isArray(method)) {
+      // multiple rpc batch call
+      requestJSON = [];
+      method.forEach(function(batchCall, i) {
+        requestJSON.push({
+          id: time + '-' + i,
+          method: batchCall.method,
+          params: batchCall.params
+        });
+      });
+    } else {
+      // single rpc call
+      requestJSON = {
+        id: time,
+        method: method,
+        params: params
+      };
+    }
 
     // First we encode the request into JSON
-    var requestJSON = JSON.stringify({
-      'id': '' + (new Date()).getTime(),
-      'method': method,
-      'params': params
-    });
+    var requestJSON = JSON.stringify(requestJSON);
 
     // prepare request options
     var requestOptions = {
@@ -71,32 +89,39 @@ var Client = function(port, host, user, password) {
           return;
         }
         
-        if (decoded.hasOwnProperty('error') && decoded.error != null) {
-          if (errback) {
-            err = new Error(decoded.error.message || '');
-            if (decoded.error.code) {
-              err.code = decoded.error.code;
-            }
-            errback(err);
-          }
-        } else if (decoded.hasOwnProperty('result')) {
-          if (callback) {
-            callback(decoded.result);
-          }
-        } else {
-          if (errback) {
-            err = new Error(decoded.error.message || '');
-            if (decoded.error.code) {
-              err.code = decoded.error.code;
-            }
-            errback(err);
-          }
+        if (!Array.isArray(decoded)) {
+          decoded = [decoded];
         }
         
+        // iterate over each response, normally there will be just one
+        // unless a batch rpc call response is being processed
+        decoded.forEach(function(decodedResponse, i) {
+          if (decodedResponse.hasOwnProperty('error') && decodedResponse.error != null) {
+            if (errback) {
+              err = new Error(decodedResponse.error.message || '');
+              if (decodedResponse.error.code) {
+                err.code = decodedResponse.error.code;
+              }
+              errback(err);
+            }
+          } else if (decodedResponse.hasOwnProperty('result')) {
+            if (callback) {
+              callback(decodedResponse.result);
+            }
+          } else {
+            if (errback) {
+              err = new Error(decodedResponse.error.message || '');
+              if (decodedResponse.error.code) {
+                err.code = decodedResponse.error.code;
+              }
+              errback(err);
+            }
+          }
+        });
+        
       });
     });
-    request.write(requestJSON);
-    request.end();
+    request.end(requestJSON);
   };
 }
 

test/api.js

@@ -25,6 +25,8 @@ function notEmpty(data) {
   assert.ok(data);
 }
 
+var batchCallbackCount = 0;
+
 vows.describe('api').addBatch({
   '': {
     topic: makeClient,
@@ -134,6 +136,29 @@ vows.describe('api').addBatch({
         assert.equal(expectedValue, undefined);
       },
     },
+    'running batch of rpc calls': {
+      topic: function(client) {
+        // create batch of calls to get 10 new addresses
+        var batch = [];
+        for (var i = 0; i < 10; ++i) {
+          batch.push({
+            method: 'getnewaddress',
+            params: [test.account]
+          });
+        }
+        var self = this;
+        client.cmd(batch, function(err, address) {
+          assert.isTrue(++batchCallbackCount <= 10);
+          if (batchCallbackCount === 10) {
+            self.callback(err, address);
+          }
+        });
+      },
+      'should receive new address': function(err, address){
+        assert.equal(err, null);
+        assert.ok(address);
+      }
+    }
   },
   'invalid credentials': {
     topic: function() {