From c5a643c9f04b423fdbacb8c57b0ed7ee467eccf6 Mon Sep 17 00:00:00 2001 From: Justin SB Date: Thu, 28 Aug 2014 09:09:46 -0700 Subject: [PATCH] Add notes about adding/ignoring fields in DDP --- packages/livedata/DDP.md | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/packages/livedata/DDP.md b/packages/livedata/DDP.md index 0cb9d137f9..7172c5e955 100644 --- a/packages/livedata/DDP.md +++ b/packages/livedata/DDP.md @@ -21,6 +21,15 @@ DDP messages are JSON objects, with some fields specified to be EJSON. Each one has a `msg` field that specifies the message type, as well as other fields depending on message type. +Extra fields may be included by the client and the server; this must not be an +error. Future minor revisions of DDP might add extra fields without changing +the DDP version; the client must therefore silently ignore unknown fields. +However, the client must not send extra fields other than those documented here +or in future versions, in case these extra fields have meaning to future +servers. On the server, all field changes must be optional/ignorable for +compatability with older clients; otherwise a new protocol version would be +required. + ## Establishing a DDP Connection: ### Messages: