Send a real EventSource event for heartbeat
The EventSource connection can get stuck (in TCP half-open state*) and there's no way
for the client to detect that. This commit changes the way heartbeat is sent, instead of
sending a newline character, it sends an empty event of type heartbeat:
event: heartbeat
data:
This event doesn't have an id: field, so the client will retain its latest Last-Event-ID state.
This doesn't change the expectations of clients that used EventSource till now, because they
subscribe to the 'message' event type. To get the 'heartbeat' events a client will need to
explicitly subscribe to it:
source.addEventListener('heartbeat', function () { /* cancel a timer that would otherwise reconnect the source */ });
* this can happen when you suspend your laptop, on flaky internet connection, ADSL reconnect,
bad wifi signals, bad routers etc. Pretty often in a typical internet usage nowadays.
diff --git a/script/test/changes.js b/script/test/changes.js
index 0fba9f9..b034a0b 100644
--- a/script/test/changes.js
+++ b/script/test/changes.js
@@ -123,7 +123,7 @@
xhr = CouchDB.newXhr();
- //verify the hearbeat newlines are sent
+ //verify the heartbeat newlines are sent
xhr.open("GET", CouchDB.proxyUrl("/test_suite_db/_changes?feed=continuous&heartbeat=10&timeout=500"), true);
xhr.send("");
@@ -171,6 +171,25 @@
T(results[1].changes[0].rev == docBar._rev);
}
+ // test that we receive EventSource heartbeat events
+ if (!!window.EventSource) {
+ var source = new EventSource(
+ "/test_suite_db/_changes?feed=eventsource&heartbeat=10");
+
+ var count_heartbeats = 0;
+ source.addEventListener('heartbeat', function () { count_heartbeats = count_heartbeats + 1; } , false);
+
+ waitForSuccess(function() {
+ if (count_heartbeats < 3) {
+ throw "keep waiting";
+ }
+ return true;
+ }, "eventsource-heartbeat");
+
+ T(count_heartbeats >= 3);
+ source.close();
+ }
+
// test longpolling
xhr = CouchDB.newXhr();
