Release notes for OpenSRF 2.4.0-alpha

WebSockets are a standards-compliant, cross-browser mechanism to support streaming, bi-directional communication between the browser and the server. For more information, see http://en.wikipedia.org/wiki/WebSocket

OpenSRF now offers a WebSockets gateway via an Apache plugin as well as updates to the OpenSRF JavaScript client library to support WebSockets as a transport.

To install the WebSockets gateway, follow the instructions in README.websockets. By default, the WebSockets gateway listens on ports 7680 and 7682 and uses a separate Apache instance.

Browsers' same-origin policy currently restricts requests to the current website’s domain to prevent various nefarious scenarios. However, because APIs and other web resources need to remain open to cross-site use, Cross Origin Resource Sharing (CORS) was created to allow services to formally authorize cross-origin requests. CORS makes it simple to use OpenSRF’s HTTP translator and gateway APIs on websites using separate domains.

A couple examples of scenarios where this would be useful:

Domains that are allowed to send cross-origin requests can now be specified in opensrf_core.xml as cross_origin/origin elements in the gateway element (full XPath /config/gateway/cross_origin/origin).

Note that the OpenSRF Javascript client library (opensrf.js) currently defaults to the root of the current web host (/osrf-http-translator). In addition, synchronous requests are presumed in some situations, resulting in the oncomplete method never returning (as blocking requests are not possible with cross-domain XHR).

It is now possible to specify a log tag, i.e., a string to append to the application name in syslog message. This allows easy filtering of log entries when running multiple OpenSRF instances on the same server.

Log tags can be set by adding logtag elements in opensrf_core.xml.

The routines JSON2js and js2JSON now use native browser JSON routines. In addition, jsonPretty is removed in favor of JSON.stringify.

Users of the OpenSRF JavaScript library should note that as a consequence of this change, JSON2js will now throw an exception if it is given input not is not a valid JSON string.

The most common form of XMPP error messages are "bounced" messages, i.e. those where the recipient is not available. Instead of passing these useless and confusing messages down to a drone for processing, listeners now log the error and drop the message.

An example of when this can occur is when a service is starting up and attempts to register with a router that is not yet available.

The control script osrf_ctl.sh is removed in favor of osrf_control, which was introduced in OpenSRF 2.3.0.

Docgen output now respects formatting present in method description.

Instead of simply producing an error message in the OpenSRF logs, calls to nonexistent subroutines are now fatal errors which will stop code execution.

As of 2.3.0, OpenSRF can readily support running multiple instances on one server. This bugfix ensures that osrf_control only affects OpenSRF processes owened by the current user.