Add UUID field to exercises

This allows to uniquely identify exercises across installations, e.g. to sync
the images or similar tasks.

Fixes #110

wger/exercises/management/commands/download-exercise-images.py

@@ -51,18 +51,18 @@ class Command(BaseCommand):
     help = ('Download exercise images from wger.de and update the local database\n'
             '\n'
             'ATTENTION: The script will download the images from the server and add them\n'
-            '           to local exercises. If you happen to have edited them, the script\n'
-            '           *might* add the wrong images to the wrong exercises if they match\n'
-            '           the remote ID.')
+            '           to your local exercises. The exercises are identified by\n'
+            '           their UUID field, if you manually edited or changed it\n'
+            '           the script will not be able to match them.')
 
     def handle(self, *args, **options):
 
         if not settings.MEDIA_ROOT:
             raise ImproperlyConfigured('Please set MEDIA_ROOT in your settings file')
 
         remote_url = options['remote_url']
-        val = URLValidator()
         try:
+            val = URLValidator()
             val(remote_url)
         except ValidationError:
             raise CommandError('Please enter a valid URL')
@@ -75,13 +75,14 @@ def handle(self, *args, **options):
         result = json.load(urllib.urlopen(exercise_api.format(remote_url)))
         for exercise_json in result['results']:
             exercise_name = exercise_json['name']
+            exercise_uuid = exercise_json['uuid']
             exercise_id = exercise_json['id']
 
             self.stdout.write('')
             self.stdout.write(u"*** Processing {0} (ID: {1})".format(exercise_name, exercise_id))
 
             try:
-                exercise = Exercise.objects.get(pk=exercise_id)
+                exercise = Exercise.objects.get(uuid=exercise_uuid)
             except Exercise.DoesNotExist:
                 self.stdout.write('    Remote exercise not found in local DB, skipping...')
                 continue

wger/exercises/migrations/0002_auto_20150307_1841.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import uuid
+
+def generate_uuids(apps, schema_editor):
+    '''
+    Generate new UUIDs for each exercise
+    :param apps:
+    :param schema_editor:
+    :return:
+    '''
+    Excercise = apps.get_model("exercises", "Exercise")
+    for exercise in Excercise.objects.all():
+        exercise.uuid = uuid.uuid4()
+        exercise.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('exercises', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='exercise',
+            name='uuid',
+            field=models.CharField(editable=False, max_length=36, verbose_name='UUID', default=uuid.uuid4),
+            preserve_default=True,
+        ),
+        migrations.RunPython(generate_uuids),
+    ]

wger/exercises/models.py

@@ -16,6 +16,7 @@
 # along with Workout Manager.  If not, see <http://www.gnu.org/licenses/>.
 
 import six
+import uuid
 import logging
 import bleach
 
@@ -198,6 +199,14 @@ class Exercise(AbstractSubmissionModel, AbstractLicenseModel, models.Model):
                                  verbose_name=_('Language'))
     '''The exercise's language'''
 
+    uuid = models.CharField(verbose_name='UUID',
+                            max_length=36,
+                            editable=False,
+                            default=uuid.uuid4)
+    '''
+    Globally unique ID, to identify the exercise across installations
+    '''
+
     #
     # Django methods
     #

wger/software/templates/changelog.html

@@ -45,8 +45,9 @@ <h4>2015-XX-XX</h4>
     <li>
         Other improvements and bugfixes
         <a href="https://github.com/rolandgeider/wger/issues/99">#99</a>
-        <a href="https://github.com/rolandgeider/wger/issues/108">#100</a>
+        <a href="https://github.com/rolandgeider/wger/issues/100">#100</a>
         <a href="https://github.com/rolandgeider/wger/issues/108">#108</a>
+        <a href="https://github.com/rolandgeider/wger/issues/110">#110</a>
         <a href="https://github.com/rolandgeider/wger/issues/117">#117</a>
         <a href="https://github.com/rolandgeider/wger/issues/131">#131</a>
         <a href="https://github.com/rolandgeider/wger/issues/135">#135</a>