Add SerializedObject.check_no_missing_fields

src/js/ripple/serializedobject.js

@@ -72,11 +72,40 @@ SerializedObject.from_json = function (obj) {
                     ' TransactionType, LedgerEntryType or AffectedNodes.');
   }
 
+  // ND: This from_*json* seems a reasonable place to put validation of `json`
+  SerializedObject.check_no_missing_fields(typedef, obj);
   so.serialize(typedef, obj);
 
   return so;
 };
 
+SerializedObject.check_no_missing_fields = function (typedef, obj) {
+  var missing_fields = [];
+  
+  for (var i = typedef.length - 1; i >= 0; i--) {
+    var spec = typedef[i];
+    var field = spec[0]
+    var requirement = spec[1];
+
+    if (binformat.REQUIRED === requirement && obj[field] == null) {
+      missing_fields.push(field);
+    };
+  };
+  
+  if (missing_fields.length > 0) {
+    var object_name;
+    if (obj.TransactionType != null) {
+      object_name = SerializedObject.lookup_type_tx(obj.TransactionType);
+    } else {
+      object_name = "TransactionMetaData";
+    } /*else {
+      TODO: LedgerEntryType ... 
+    }*/
+    throw new Error(object_name + " is missing fields: " + 
+                    JSON.stringify(missing_fields));
+  };
+}
+
 SerializedObject.prototype.append = function (bytes) {
   if (bytes instanceof SerializedObject) {
     bytes = bytes.buffer;

test/serializedobject-test.js

@@ -35,6 +35,27 @@ describe('Serialized object', function() {
       assert.deepEqual(input_json, output_json);
     });
   });
+  describe('Format validation', function() {
+    // Peercover actually had a problem submitting transactions without a `Fee`
+    // and rippled was only informing of "transaction is invalid"
+    it('should throw an Error when there is a missing field', function() {
+      var input_json = {
+        Account: 'r4qLSAzv4LZ9TLsR7diphGwKnSEAMQTSjS',
+        Amount: '274579388',
+        Destination: 'r4qLSAzv4LZ9TLsR7diphGwKnSEAMQTSjS',
+        Sequence: 351,
+        SigningPubKey: '02854B06CE8F3E65323F89260E9E19B33DA3E01B30EA4CA172612DE77973FAC58A',
+        TransactionType: 'Payment',
+        TxnSignature: '30450221009DA3A42DD25E3B22EC45AD8BA8FC7A954264264A816D300B2DF69F814D7D4DD2022072C9627F97EEC6DA13DE841E06E2CD985EF06A0FBB15DDBF0800D0730C8986BF'
+      };
+      assert.throws (
+        function() {
+          var output_json = SerializedObject.from_json(input_json);
+        },
+        /Payment is missing fields: \["Fee"\]/
+      );
+    });
+  });
 });
 
 // vim:sw=2:sts=2:ts=8:et