From c13733960eda3d776e0b7a8f989d49cc5470782a Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <me@steffo.eu>
Date: Sun, 18 Apr 2021 19:37:32 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=94=A7=20Make=20sync=5Fflows=20a=20model?=
 =?UTF-8?q?=20method=20instead=20of=20a=20viewset=20action?=
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---
 backend/sophon/core/models.py | 31 +++++++++++++++++++++++++++++++
 backend/sophon/core/views.py  | 27 ++-------------------------
 2 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/backend/sophon/core/models.py b/backend/sophon/core/models.py
index 04c961e..82febd9 100644
--- a/backend/sophon/core/models.py
+++ b/backend/sophon/core/models.py
@@ -7,6 +7,10 @@ import pandasdmx.message
 import typing as t
 import json
 import abc
+import datetime
+import logging
+
+log = logging.getLogger(__name__)
 
 
 class DataSource(models.Model):
@@ -260,6 +264,33 @@ class DataSource(models.Model):
         structs = data["structure"]
         return flows, structs
 
+    def sync_flows(self) -> None:
+        """
+        Create :class:`.DataFlow` objects for every dataflow returned by :meth:`.request_flows`, and update the ones
+        that already exist.
+
+        .. warning:: This function does not delete any :class:`.DataFlow`, even if it doesn't exist anymore!
+        """
+
+        log.debug(f"Requesting dataflows of {self!r}...")
+        flows, structs = self.request_flows()
+
+        log.info(f"Syncing DataFlows of {self!r}...")
+        for description, sdmx_id in zip(flows, flows.index):
+
+            db_flow = DataFlow.objects.update_or_create(
+                **{
+                    "datasource": self,
+                    "id": sdmx_id,
+                },
+                defaults={
+                    "last_update": datetime.datetime.now(),
+                    "description": description,
+                }
+            )
+            db_flow.save()
+            log.info(f"Synced {db_flow}!")
+
     def __str__(self):
         return self.id
 
diff --git a/backend/sophon/core/views.py b/backend/sophon/core/views.py
index ece35b4..6b0eaa7 100644
--- a/backend/sophon/core/views.py
+++ b/backend/sophon/core/views.py
@@ -67,31 +67,8 @@ class DataSourceViewSet(viewsets.ModelViewSet):
 
         log.debug(f"Getting DataSource from the database...")
         db_datasource: models.DataSource = self.get_object()
-
-        log.debug(f"Requesting dataflows of {db_datasource!r}...")
-        flows, structs = db_datasource.request_flows()
-
-        log.info(f"Syncing DataFlows of {db_datasource!r}...")
-        for description, sdmx_id in zip(flows, flows.index):
-
-            log.debug(f"Searching in the database for: {db_datasource!r} | {sdmx_id!r}")
-            try:
-                db_flow = models.DataFlow.objects.get(datasource_id=db_datasource, sdmx_id=sdmx_id)
-            except models.DataFlow.DoesNotExist:
-                db_flow = models.DataFlow(
-                    datasource_id=db_datasource,
-                    sdmx_id=sdmx_id,
-                    last_update=datetime.now(),
-                    description=description,
-                )
-                log.info(f"Created new DataFlow: {db_flow!r}")
-            else:
-                db_flow.last_update = datetime.now()
-                db_flow.description = description
-                log.debug(f"Updated DataFlow: {db_flow!r}")
-
-            db_flow.save()
+        db_datasource.sync_flows()
 
         return response.Response({
-            "updated": len(flows)
+            "success": True,
         })