refactor list operation

all operations mix together make it very difficult to read

Change-Id: I7e4a12fd13a7aa0dc0c8fc09b69c7e43a2ab18ac
Signed-off-by: SerenaFeng <feng.xiaowei@zte.com.cn>

1 files changed, 42 insertions, 26 deletions

diff --git a/testapi/opnfv_testapi/resources/handlers.py b/testapi/opnfv_testapi/resources/handlers.py
index 5c98c48..c7fed8f 100644
--- a/testapi/opnfv_testapi/resources/handlers.py
+++ b/testapi/opnfv_testapi/resources/handlers.py
@@ -101,55 +101,71 @@ class GenericApiHandler(web.RequestHandler):
     @web.asynchronous
     @gen.coroutine
     def _list(self, query=None, res_op=None, *args, **kwargs):
-        if query is None:
-            query = {}
-        data = []
         sort = kwargs.get('sort')
         page = kwargs.get('page', 0)
         last = kwargs.get('last', 0)
         per_page = kwargs.get('per_page', 0)
-
+        if query is None:
+            query = {}
         cursor = self._eval_db(self.table, 'find', query)
         records_count = yield cursor.count()
-        records_nr = records_count
-        if (records_count > last) and (last > 0):
-            records_nr = last
-
-        pipelines = list()
-        if query:
-            pipelines.append({'$match': query})
-        if sort:
-            pipelines.append({'$sort': sort})
-
-        if page > 0:
-            total_pages, remainder = divmod(records_nr, per_page)
-            if remainder > 0:
-                total_pages += 1
-            pipelines.append({'$skip': (page - 1) * per_page})
-            pipelines.append({'$limit': per_page})
-        elif last > 0:
-            pipelines.append({'$limit': last})
-
+        total_pages = self._calc_total_pages(records_count,
+                                             last,
+                                             page,
+                                             per_page)
+        pipelines = self._set_pipelines(query, sort, last, page, per_page)
         cursor = self._eval_db(self.table,
                                'aggregate',
                                pipelines,
                                allowDiskUse=True)
-
+        data = list()
         while (yield cursor.fetch_next):
             data.append(self.format_data(cursor.next_object()))
         if res_op is None:
             res = {self.table: data}
         else:
             res = res_op(data, *args)
-        if page:
+        if total_pages > 0:
             res.update({
                 'pagination': {
-                    'current_page': page,
+                    'current_page': kwargs.get('page'),
                     'total_pages': total_pages
                 }
             })
         self.finish_request(res)
 
+    @staticmethod
+    def _calc_total_pages(records_count, last, page, per_page):
+        records_nr = records_count
+        if (records_count > last) and (last > 0):
+            records_nr = last
+
+        total_pages = 0
+        if page > 0:
+            total_pages, remainder = divmod(records_nr, per_page)
+            if remainder > 0:
+                total_pages += 1
+        if page > total_pages:
+            raises.BadRequest(
+                'Request page > total_pages [{}]'.format(total_pages))
+        return total_pages
+
+    @staticmethod
+    def _set_pipelines(query, sort, last, page, per_page):
+        pipelines = list()
+        if query:
+            pipelines.append({'$match': query})
+        if sort:
+            pipelines.append({'$sort': sort})
+
+        if page > 0:
+            pipelines.append({'$skip': (page - 1) * per_page})
+            pipelines.append({'$limit': per_page})
+        elif last > 0:
+            pipelines.append({'$limit': last})
+
+        return pipelines
+
     @web.asynchronous
     @gen.coroutine
     @check.not_exist