The document discusses an EventSource emulation enabler that allows the EventSource API to be used in browsers that do not natively support server-sent events. The enabler provides a simple pushed messaging API for web applications. When more browsers implement EventSource natively, applications will automatically start using the native implementation instead of the emulation. Examples are provided for how to use the enabler client-side and serve events from the server.

1. EventSource emulation
A labs.ericsson.com enabler
https://labs.ericsson.com/apis/eventsource/

2. EventSource emulation
EventSource is an API for receiving push messages “server-
sent events” that is currently being standardized and
implemented natively in browsers.
The EventSource emulation enabler allows you to use the
EventSource API already now in browsers that do not yet
support server-sent events.
Additionally, the enabler proxy allows you to set up your own
server that provides a regular event-stream that will work
with a native implementation of EventSource.
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3. Why EventSource emulation?
The EventSource emulation enabler
provides a simple API for receiving
pushed messages to web applications
that you can use already today.
Once more browsers implements the
EventSource functionality natively,
your web application will then start
using the native implementation
automatically.
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4. EventSource client example
To use the enabler, simply include the enabler
JavaScript as such:
<script src="http://eventsource.labs.ericsson.net
/ESProxy/library/?key=YOUR_API_KEY"></script>
Use the EventSource constructor to start receiving
events from your server:
var es = new EventSource(“http://example.org/event-stream”);
Add an event listener to the EventSource object to
handle incoming events:
es.addEventListener(“server-time”, function (evt) { alert(“time on
server is:” + evt.data); }, false);
The EventSource specification is available here:
http://dev.w3.org/html5/eventsource/
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5. EventSource server example
A simple PHP script can be used to serve the client
with an appropriate event-stream:
<?php
header("Content-Type:text/event-stream");
while(true) {
echo "event: server-timen";
$time = time();
echo "data: $timen";
echo "n";
flush();
sleep(3);
}
?>
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