Added the "group by" option in the select method of the mongodb datasource and started the implementation of the migration handler

lodel/datasource/generic/migrationhandler.py

@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+
+## @package lodel.datasource.migrationhandler.generic
+# @brief A generic migration handler
+#
+# According to it, every moditification is possible
+#
+
+
+## Manage model changes
+class GenericMigrationHandler(object):
+
+    def __init__(self, debug=False):
+        self.debug = debug
+
+    ## @brief Records a change in the EditorialModel and indicates whether or not it is possible to make it
+    # @note The states (initial_state and new_state) contains only fields that changes
+    def register_change(self, em, uid, initial_state, new_state):
+        if self.debug:
+            print("\n##############")
+            print("GenericMigrationHandler debug. Changes for component with uid %s :" % uid)
+            if initial_state is None:
+                print("Component creation (uid = %s): \n\t" % uid, new_state)
+            elif new_state is None:
+                print("Component deletion (uid = %s): \n\t" % uid, initial_state)
+            else:
+                field_list = set(initial_state.keys()).union(set(new_state.keys()))
+                for field_name in field_list:
+                    str_chg = "\t%s " % field_name
+                    if field_name in initial_state:
+                        str_chg += "'" + str(initial_state[field_name]) + "'"
+                    else:
+                        str_chg += " creating "
+                    str_chg += " => "
+                    if field_name in new_state:
+                        str_chg += "'" + str(new_state[field_name]) + "'"
+                    else:
+                        str_chg += " deletion "
+                    print(str_chg)
+
+            print("##############\n")
+
+    ## @brief Not usefull for the moment
+    def register_model_state(self, em, state_hash):
+        if self.debug:
+            print("New EditorialModel state registered : '%s'" % state_hash)

lodel/datasource/mongodb/datasource.py

@@ -1,4 +1,8 @@
 # -*- coding: utf-8 -*-
+
+import bson
+from bson.son import SON
+from collections import OrderedDict
 import pymongo
 from pymongo import MongoClient
 from pymongo.errors import BulkWriteError
@@ -64,12 +68,11 @@ class MongoDbDataSource(GenericDataSource):
     # @param filters list : List of filters
     # @param rel_filters list : List of relational filters
     # @param order list : List of column to order. ex: order = [('title', 'ASC'),]
-    # @param group list : List of tupple representing the column to group together. ex: group = [('title', 'ASC'),]
+    # @param group list : List of tupple representing the column used as "group by" fields. ex: group = [('title', 'ASC'),]
     # @param limit int : Number of records to be returned
     # @param offset int: used with limit to choose the start record
     # @param instanciate bool : If true, the records are returned as instances, else they are returned as dict
     # @return list
-    # @todo Implement the grouping
     # @todo Implement the relations
     def select(self, target_cls, field_list, filters, rel_filters=None, order=None, group=None, limit=None, offset=0,
                instanciate=True):
@@ -79,13 +82,41 @@ class MongoDbDataSource(GenericDataSource):
         query_result_ordering = utils.parse_query_order(order) if order is not None else None
         results_field_list = None if len(field_list) == 0 else field_list
         limit = limit if limit is not None else 0
-        cursor = collection.find(
-            filter=query_filters,
-            projection=results_field_list,
-            skip=offset,
-            limit=limit,
-            sort=query_result_ordering
-        )
+
+        if group is None:
+            cursor = collection.find(
+                filter=query_filters,
+                projection=results_field_list,
+                skip=offset,
+                limit=limit,
+                sort=query_result_ordering
+            )
+        else:
+            pipeline = list()
+            unwinding_list = list()
+            grouping_dict = OrderedDict()
+            sorting_list = list()
+            for group_param in group:
+                field_name = group_param[0]
+                field_sort_option = group_param[1]
+                sort_option = utils.MONGODB_SORT_OPERATORS_MAP[field_sort_option]
+                unwinding_list.append({'$unwind': '$%s' % field_name})
+                grouping_dict[field_name] = '$%s' % field_name
+                sorting_list.append((field_name, sort_option))
+
+            sorting_list.extends(query_result_ordering)
+
+            pipeline.append({'$match': query_filters})
+            if results_field_list is not None:
+                pipeline.append({'$project': SON([{field_name: 1} for field_name in field_list])})
+            pipeline.extend(unwinding_list)
+            pipeline.append({'$group': grouping_dict})
+            pipeline.extend({'$sort': SON(sorting_list)})
+            if offset > 0:
+                pipeline.append({'$skip': offset})
+            if limit is not None:
+                pipeline.append({'$limit': limit})
+
         results = list()
         for document in cursor:
             results.append(document)

lodel/datasource/mongodb/migration_handler.py

@@ -1 +1,51 @@
-# -*- coding: utf-8 -*-
+# -*- coding: utf-8 -*-
+
+from lodel.datasource.generic.migrationhandler import GenericMigrationHandler
+from lodel.datasource.mongodb.datasource import MongoDbDataSource
+from lodel.editorial_model.components import EmClass, EmField
+class MigrationHandlerChangeError(Exception):
+    pass
+
+## @brief Modifies a MongoDb database given editorial model changes
+class MongoDbMigrationHandler(GenericMigrationHandler):
+
+    ## @brief constructs a MongoDbMigrationHandler
+    # @param conn_args dict : a dictionary containing connection options
+    # @param **kwargs : extra arguments given to the connection methods
+    def __init__(self, conn_args=None, **kwargs):
+        if conn_args is None:
+            conn_args = {}  # TODO : récupérer les options de connexion dans les settings
+            self.connection_name = conn_args['name']
+            # del conn_args['module']
+
+        self.db_conn = MongoDbDataSource(self.connection_name)
+        # TODO Réimplémenter la partie sur les settings
+        mh_settings = {}
+        self.dryrun = kwargs['dryrun'] if 'dryrun' in kwargs else mh_settings['dryrun']
+        self.foreign_keys = kwargs['foreign_keys'] if 'foreign_keys' in kwargs else mh_settings['foreign_keys']
+        self.drop_if_exists = kwargs['drop_if_exists'] if 'drop_if_exists' in kwargs else mh_settings['drop_if_exists']
+        self._create_default_collections(self.drop_if_exists)
+
+    ## @brief Modify the database given an EM change
+    #
+    # @param em model : The EditorialModel.model object to provide the global context.
+    # @param uid str : The uid of the changed component.
+    # @param initial_state dict|None : dict with field name as key and field value as value. Represents the original state. None means it's a creation of a new component.
+    # @param new_state dict|None : dict with field name as key and field value as value. Represents the new state. None means it's a component deletion.
+    # @throw MigrationHandlerChangeError if the change was refused
+    def register_change(self, em, uid, initial_state, new_state):
+        if isinstance(em.classes(uid), EmClass):
+            if initial_state is None:
+                # EmClass creation
+                self.create_emclass_collection(em, uid)
+            elif new_state is None:
+                # EmClass deletion
+                self.delete_emclass_collection(em, uid)
+        elif isinstance(em.classes(uid), EmField):
+            emfield = em.
+
+        pass
+
+
+    def _create_default_collections(self, drop_if_exist=False):
+        pass

lodel/datasource/mongodb/utils.py

@@ -25,6 +25,10 @@ LODEL_SORT_OPERATORS_MAP = {
     'DESC': pymongo.DESCENDING
 }
 
+MONGODB_SORT_OPERATORS_MAP = {
+    'ASC': 1,
+    'DESC': -1
+}
 
 ## @brief Returns a collection name given a Emclass name
 # @param class_name str : The class name