Bump DDP version from "pre2" to "1"

Still let old clients connect to a server running this new version

packages/ddp/DDP.md

@@ -7,7 +7,7 @@ DDP is a protocol between a client and a server that supports two operations:
    client informed about the contents of those documents as they change over
    time.
 
-This document specifies the version "pre2" of DDP. It's a rough description of
+This document specifies the version "1" of DDP. It's a rough description of
 the protocol and not intended to be entirely definitive.
 
 ## General Message Structure:
@@ -21,6 +21,14 @@ 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.
 
+The client and the server must ignore any unknown fields in messages.  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 in the DDP protocol, 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:
@@ -324,3 +332,14 @@ behaves differently to the server, then syncing will fix this.
 
 * If both client and server support randomSeed, in the normal case the ids
 generated will be the same, and syncing will be a no-op.
+
+
+## Version History
+
+```pre1``` was the first version of DDP
+
+```pre2``` added keep-alive (ping & pong messages), and randomSeed.
+
+```1``` should be considered the first official version of DDP.  It is
+currently identical to pre2, although non-incompatible changes may be made to
+it in future.

packages/ddp/livedata_common.js

@@ -1,4 +1,6 @@
-SUPPORTED_DDP_VERSIONS = [ 'pre2', 'pre1' ];
+// All the supported versions (for both the client and server)
+// These must be in order of preference; most favored-first
+SUPPORTED_DDP_VERSIONS = [ '1', 'pre2', 'pre1' ];
 
 LivedataTest.SUPPORTED_DDP_VERSIONS = SUPPORTED_DDP_VERSIONS;
 

packages/ddp/livedata_connection_tests.js

@@ -1407,6 +1407,40 @@ Tinytest.add("livedata connection - ping with id", function (test) {
   testGotMessage(test, stream, {msg: 'pong', id: id});
 });
 
+_.each(LivedataTest.SUPPORTED_DDP_VERSIONS, function (version) {
+  Tinytest.addAsync("livedata connection - ping from " + version,
+                    function (test, onComplete) {
+    var connection = new LivedataTest.Connection(getSelfConnectionUrl(), {
+      reloadWithOutstanding: true,
+      supportedDDPVersions: [version],
+      onDDPVersionNegotiationFailure: function () { test.fail(); onComplete(); },
+      onConnected: function () {
+        test.equal(connection._version, version);
+        // It's a little naughty to access _stream and _send, but it works...
+        connection._stream.on('message', function (json) {
+          var msg = JSON.parse(json);
+          var done = false;
+          if (msg.msg === 'pong') {
+            test.notEqual(version, "pre1");
+            done = true;
+          } else if (msg.msg === 'error') {
+            // Version pre1 does not play ping-pong
+            test.equal(version, "pre1");
+            done = true;
+          } else {
+            Meteor._debug("Got unexpected message: " + json);
+          }
+          if (done) {
+            connection._stream.disconnect({_permanent: true});
+            onComplete();
+          }
+        });
+        connection._send({msg: 'ping'});
+      }
+    });
+  });
+});
+
 var getSelfConnectionUrl = function () {
   if (Meteor.isClient) {
     return Meteor._relativeToSiteRootUrl("/");