Introduced a PgAdmin class inherited from the Flask, which looks for

submodules inherited from the PgAdminModule instead of regular
Blueprint. This allows us to load the module automatically from the
under the pgadmin directory, and will work to extend the pgAdmin
extension module.

PgAdminModule is inherited from the Blueprint, and bring several
methods:
-  get_own_stylesheets, which returns the stylesheets used by the module
   (excluding its submodules stylesheets)
- get_own_javascripts
- menu_items, which returns a dictionray mapping the old hook names
  (context_items etc) to a list of MenuItem instances

For more specialized modules (as for now, any module that should be part
of the browser tree construction), one can define an abstract base class
defining additional methods.

For example, the BrowserPluginModule abstract base class defines the
following methods:
- jssnippets
- csssnipeets
- node_type
- get_nodes

web/pgadmin/browser/server_groups/__init__.py

@@ -6,10 +6,202 @@
 # This software is released under the PostgreSQL Licence
 #
 ##########################################################################
+"""Defines views for management of server groups"""
 
-# Node meta data
-NODE_TYPE = 'server-group'
-NODE_PATH = '/browser/nodes/' + NODE_TYPE
+from abc import ABCMeta, abstractmethod
+import traceback
+from flask import Blueprint, Response, current_app, request, render_template
+from flask.ext.babel import gettext
+from flask.ext.security import current_user, login_required
+from pgadmin import current_blueprint
+from pgadmin.utils.ajax import make_json_response
+from pgadmin.browser import BrowserPluginModule
+from pgadmin.utils.menu import MenuItem
+from pgadmin.settings.settings_model import db, ServerGroup
+import config
 
-# Define the child node list
-sub_nodes = [ ]
+
+
+class ServerGroupModule(BrowserPluginModule):
+
+    NODE_TYPE = "server-group"
+
+    def get_own_menuitems(self):
+        return {
+            'standard_items': [
+                ServerGroupMenuItem(action="drop", priority=10, function="drop_server_group"),
+                ServerGroupMenuItem(action="rename", priority=10, function="rename_server_group")
+            ],
+            'create_items': [
+                ServerGroupMenuItem(name="create_server_group",
+                                    label=gettext('Server Group...'),
+                                    priority=10,
+                                    function="create_server_group",
+                                    types=[self.node_type])
+            ],
+            'context_items': [
+                ServerGroupMenuItem(name="delete_server_group",
+                                    label=gettext('Delete server group'),
+                                    priority=10,
+                                    onclick='drop_server_group(item);'),
+                ServerGroupMenuItem(name="rename_server_group",
+                                    label=gettext('Rename server group...'),
+                                    priority=10,
+                                    onclick='rename_server_group(item);')
+            ]
+        }
+
+
+    @property
+    def jssnippets(self):
+        snippets = [render_template("server_groups/server_groups.js")]
+        for module in self.submodules:
+            snippets.extend(module.jssnippets)
+        return snippets
+
+    def get_nodes(self, **kwargs):
+        """Return a JSON document listing the server groups for the user"""
+        groups = ServerGroup.query.filter_by(user_id=current_user.id)
+        # TODO: Move this JSON generation to a Server method
+        # this code is duplicated somewhere else
+        for group in groups:
+            yield {
+                "id": "%s/%d" % (self.node_type, group.id),
+                "label": group.name,
+                "icon": "icon-%s" % self.node_type,
+                "inode": True,
+                "_type": self.node_type
+            }
+
+    @property
+    def node_type(self):
+        return self.NODE_TYPE
+
+
+
+class ServerGroupMenuItem(MenuItem):
+
+    def __init__(self, **kwargs):
+        kwargs.setdefault("type", ServerGroupModule.NODE_TYPE)
+        super(ServerGroupMenuItem, self).__init__(**kwargs)
+
+
+class ServerGroupPluginModule(BrowserPluginModule):
+    """
+    Base class for server group plugins.
+    """
+
+    __metaclass__ = ABCMeta
+
+
+    @abstractmethod
+    def get_nodes(self, servergroup):
+        pass
+
+
+# Initialise the module
+blueprint = ServerGroupModule( __name__, static_url_path='')
+
+@blueprint.route("/<server_group>")
+@login_required
+def get_nodes(server_group):
+    """Build a list of treeview nodes from the child nodes."""
+    nodes = []
+    for module in current_blueprint.submodules:
+        nodes.extend(module.get_nodes(server_group=server_group))
+    return make_json_response(data=nodes)
+
+
+@blueprint.route('/add/', methods=['POST'])
+@login_required
+def add():
+    """Add a server group node to the settings database"""
+    success = 1
+    errormsg = ''
+    data = { }
+
+    if request.form['name'] != '':
+        servergroup = ServerGroup(user_id=current_user.id, name=request.form['name'])
+
+        try:
+            db.session.add(servergroup)
+            db.session.commit()
+        except Exception as e:
+            success = 0
+            errormsg = e.message
+
+    else:
+        success = 0
+        errormsg = gettext('No server group name was specified')
+
+    if success == 1:
+        data['id'] = servergroup.id
+        data['name'] = servergroup.name
+
+    return make_json_response(success=success,
+                              errormsg=errormsg,
+                              info=traceback.format_exc(),
+                              result=request.form,
+                              data=data)
+
+@blueprint.route('/delete/', methods=['POST'])
+@login_required
+def delete():
+    """Delete a server group node in the settings database"""
+    success = 1
+    errormsg = ''
+
+    if request.form['id'] != '':
+        # There can be only one record at most
+        servergroup = ServerGroup.query.filter_by(user_id=current_user.id, id=int(request.form['id'])).first()
+
+        if servergroup is None:
+            success = 0
+            errormsg = gettext('The specified server group could not be found.')
+        else:
+            try:
+                db.session.delete(servergroup)
+                db.session.commit()
+            except Exception as e:
+                success = 0
+                errormsg = e.message
+
+    else:
+        success = 0
+        errormsg = gettext('No server group  was specified.')
+
+    return make_json_response(success=success,
+                              errormsg=errormsg,
+                              info=traceback.format_exc(),
+                              result=request.form)
+
+@blueprint.route('/rename/', methods=['POST'])
+@login_required
+def rename():
+    """Rename a server group node in the settings database"""
+    success = 1
+    errormsg = ''
+
+    if request.form['id'] != '':
+        # There can be only one record at most
+        servergroup = ServerGroup.query.filter_by(user_id=current_user.id, id=int(request.form['id'])).first()
+
+        if servergroup is None:
+            success = 0
+            errormsg = gettext('The specified server group could not be found.')
+        else:
+            try:
+                servergroup.name = request.form['name']
+                db.session.commit()
+            except Exception as e:
+                success = 0
+                errormsg = e.message
+
+    else:
+        success = 0
+        errormsg = gettext('No server group was specified.')
+
+    return make_json_response(success=success,
+                              errormsg=errormsg,
+                              info=traceback.format_exc(),
+                              result=request.form)