view mod_pubsub_eventsource/README.markdown @ 5801:73887dcb2129

mod_pubsub_serverinfo: New module that uses pub/sub to make accessible server info This first implemetnation is laughably simple: it only adds a disco#info feature. This flags 'opt-in' for inclusion of local domain names in the data exposed by other domains (per the domain), which will allow servers to be listed in the XMPP Network Graph at https://xmppnetwork.goodbytes.im Hopefully, this bare-boned implementation acts as a stepping stone for future improvements.
author Guus der Kinderen <guus.der.kinderen@gmail.com>
date Thu, 28 Dec 2023 11:02:35 +0100
parents 4d73a1a6ba68
children 694b62d8a82f
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---
labels: 'Stage-Beta'
summary: Subscribe to pubsub nodes using the HTML5 EventSource API
...

Introduction
------------

[Server-Sent Events](https://en.wikipedia.org/wiki/Server-sent_events)
is a simple HTTP/line-based protocol supported in HTML5, making it easy
to receive a stream of "events" in realtime using the Javascript
[EventSource
API](https://developer.mozilla.org/en-US/docs/Web/API/EventSource).

EventSource is supported in [most modern
browsers](http://caniuse.com/#feat=eventsource), and for the remainder
there are 'polyfill' compatibility layers such as
[EventSource.js](https://github.com/remy/polyfills/blob/master/EventSource.js)
and [jquery.eventsource](https://github.com/rwldrn/jquery.eventsource).

Details
-------

Subscribing to a node from Javascript is easy:

    var source = new EventSource('http://pubsub.example.org:5280/eventsource/mynode');
    source.onmessage = function (event) {
      console.log(event.data); // Do whatever you want with the data here
    };

### Cross-domain issues

The same cross-domain restrictions apply to EventSource that apply to
BOSH, and support for CORS is not clearly standardized yet. You may want
to proxy connections through your web server for this reason. See [BOSH:
Cross-domain
issues](https://prosody.im/doc/setting_up_bosh#proxying_requests) for
more information.

Configuration
-------------

There is no special configuration for this module. Simply load it onto a
pubsub component like so:

    Component "pubsub.example.org" "pubsub"
      modules_enabled = { "pubsub_eventsource" }

As it uses HTTP to serve the event streams, you can use Prosody's
standard [HTTP configuration options](https://prosody.im/doc/http) to
control how/where the streams are served.

**Note about URLs:** It is important to get the event streams from the
correct hostname (that of the pubsub host). An example stream URL is
`http://pubsub.example.org:5280/eventsource/mynode`. If you need to
access the streams using another hostname (e.g. `example.org`) you can
use the `http_host` option under the Component, e.g.
`http_host = "example.org"`. For more information see the ['Virtual
Hosts'](https://prosody.im/doc/http#virtual_hosts) section of our HTTP
documentation.

Compatibility
-------------

  ------- --------------
  0.9     Works
  0.8     Doesn't work
  Trunk   Works
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