view mod_pubsub_eventsource/README.markdown @ 5285:8e1f1eb00b58

mod_sasl2_fast: Fix harmless off-by-one error (invalidates existing tokens!) Problem: This was causing the key to become "<token>--cur" instead of the expected "<token>-cur". As the same key was used by the code to both set and get, it still worked. Rationale for change: Although it worked, it's unintended, inconsistent and messy. It increases the chances of future bugs due to the unexpected format. Side-effects of change: Existing '--cur' entries will not be checked after this change, and therefore existing FAST clients will fail to authenticate until they attempt password auth and obtain a new FAST token. Existing '--cur' entries in storage will not be cleaned up by this commit, but this is considered a minor issue, and okay for the relatively few FAST deployments.
author Matthew Wild <mwild1@gmail.com>
date Wed, 29 Mar 2023 16:12:15 +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
  ------- --------------