Connection provider and decorators in webclient

[atarkowska]

Review

Due to the changes in #6387, Web should have one common strategy to create connection, keep it alive and retrieve in specific use cases. That is also related to decorators.

Tickets - DRAFT ONLY!!!

Examples of common functionality that exists (and could be moved to decorators) or that we might want to provide via decorators.

• Error handling, connection & redirect or error if json.

conn = None
    try:
        conn = kwargs["conn"]
    except:
        logger.error(traceback.format_exc())
        return handlerInternalError("Connection is not available. Please contact your administrator.")

• Would be nice to allow 3rd party developers to specify templates. E.g. as in webgateway

  def full_viewer(request, iid, server_id=None, _conn=None, **kwargs):
      ....
      template = kwargs.get('template', "webgateway/omero_image.html")
      ...etc.
  

• Also we have this a lot

      t = template_loader.get_template(template)
      c = Context(request,context)
      logger.debug('TEMPLATE: '+template)
      return HttpResponse(t.render(c))
  

# check menu
    menu = request.REQUEST.get("menu")
    if menu is not None:
        request.session['nav']['menu'] = menu
    else:
        menu = request.session['nav']['menu']
    # check view
    view = request.REQUEST.get("view")
    if view is not None:
        request.session['nav']['view'] = view
    else:
        view = request.session['nav']['view']

These lines (or equivalent) are needed in many views

request.session['nav']['menu'] = menu      # menu is 'usertags', 'userdata', 'search' etc. for main menu selection
context['nav'] = request.session['nav']

Due to various parameters added to the request in isUserConnected

def sessionHelper(request):
    ...
    request.session['nav']={"blitz": blitz, "menu": "mydata", "view": "tree", "basket": 0, "experimenter":None}

def navHelper(request, conn):
    ...
    request.session['nav']['tab_links'] = links

Existing Decorator Examples

• Python Decorator Library (​http://wiki.python.org/moin/PythonDecoratorLibrary)
• Beaker (​http://beaker.groovie.org/caching.html#decorator-api)
• TurboGears @validate(), @expose(), etc. (​http://turbogears.org/2.0/docs/modules/tgdecorators.html)
• Pylons @validate(), @jsonify(), etc. (​http://docs.pylonsproject.org/projects/pylons-webframework/en/latest/modules/decorators.html)

Shares & Sessions

Previous to 4.4, the creation of sessions for shares used the stored username/password to create a new session. Part of the refactoring described above will remove that stored username/password. However, it is not necessarily possible for a user to create a new session from an existing session (this is only allowed if the session is authenticated with a password). Nevertheless it is necessary to be able to activate a session for one user in one process without effecting the other processes that are currently using the same process. Josh and Chris have agreed that extending the {"omero.group":"1"} functionality to also support shares should simplify things greatly. Each method invocation, regardless of group or session, can pass a share setting essentially activating that share for the duration of the method call. This will take place as a part of #3529.

[agilo]

Updated status, related task in progress

[cxallan]

Integration branch now available for OMERO.web:

• ​https://github.com/chris-allan/openmicroscopy/tree/6342_integration