[repository] provide a .new_session entry point
The current .connect only returns a `sessionid` which must be given to
repo._get_session(...) to get the real session object.
Related to #4151635.
What's new in CubicWeb 3.15?
============================
New functionnalities
--------------------
* Add Zmq server, based on the cutting edge ZMQ (http://www.zeromq.org/) socket
library. This allows to access distant instance, in a similar way as Pyro.
* Publish/subscribe mechanism using ZMQ for communication among cubicweb
instances. The new zmq-address-sub and zmq-address-pub configuration variables
define where this communication occurs. As of this release this mechanism is
used for entity cache invalidation.
* Improved WSGI support. While there is still some caveats, most of the code
which was twisted only is now generic and allows related functionalities to work
with a WSGI front-end.
* Full undo/transaction support : undo of modification has eventually been
implemented, and the configuration simplified (basically you activate it or not
on an instance basis).
* Controlling HTTP status code used is not much more easier :
- `WebRequest` now has a `status_out` attribut to control the response status ;
- most web-side exceptions take an optional ``status`` argument.
API changes
-----------
* The base registry implementation has been moved to a new
`logilab.common.registry` module (see #1916014). This includes code from :
* `cubicweb.vreg` (the whole things that was in there)
* `cw.appobject` (base selectors and all).
In the process, some renaming was done:
* the top level registry is now `RegistryStore` (was `VRegistry`), but that
should not impact cubicweb client code ;
* former selectors functions are now known as "predicate", though you still use
predicates to build an object'selector ;
* for consistency, the `objectify_selector` decoraror has hence be renamed to
`objectify_predicate` ;
* on the CubicWeb side, the `selectors` module has been renamed to
`predicates`.
Debugging refactoring dropped the more need for the `lltrace` decorator. There
should be full backward compat with proper deprecation warnings. Notice the
`yes` predicate and `objectify_predicate` decorator, as well as the
`traced_selection` function should now be imported from the
`logilab.common.registry` module.
* All login forms are now submitted to <app_root>/login. Redirection to requested
page is now handled by the login controller (it was previously handle by the
session manager).
* `Publisher.publish` has been renamed to `Publisher.handle_request`. This
method now contains generic version of logic previously handled by
Twisted. `Controller.publish` is **not** affected.
Unintrusive API changes
-----------------------
* New 'ldapfeed' source type, designed to replace 'ldapuser' source with
data-feed (i.e. copy based) source ideas.
* New 'zmqrql' source type, similar to 'pyrorql' but using ømq instead of Pyro.
* A new registry called `services` has appeared, where you can register
server-side `cubicweb.server.Service` child classes. Their `call` method can be
invoked from a web-side AppObject instance using new `self._cw.call_service`
method or a server-side one using `self.session.call_service`. This is a new
way to call server-side methods, much cleaner than monkey patching the
Repository class, which becomes a deprecated way to perform similar tasks.
* a new `ajax-func` registry now hosts all remote functions (i.e. functions
callable through the `asyncRemoteExec` JS api). A convenience `ajaxfunc`
decorator will let you expose your python function easily without all the
appobject standard boilerplate. Backward compatibility is preserved.
* the 'json' controller is now deprecated in favor of the 'ajax' one.
* `WebRequest.build_url` can now take a __secure__ argument. When True cubicweb
try to generate an https url.
User interface changes
----------------------
A new 'undohistory' view expose the undoable transactions and give access to undo
some of them.