certificate: change certificate generation workflow

courses/certification/apps.py

@@ -3,3 +3,6 @@ from django.apps import AppConfig
 
 class CoursesCertificationConfig(AppConfig):
     name = 'courses.certification'
+
+    def ready(self):
+        import courses.certification.signals
\ No newline at end of file

courses/certification/migrations/0003_auto_20200630_2323.py

+# Generated by Django 2.2.13 on 2020-07-01 02:23
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('certification', '0002_certificatedata'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='certificatedata',
+            name='workspace',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, to='courses.Workspace'),
+        ),
+    ]

courses/certification/models.py

@@ -287,6 +287,7 @@ class CertificateData(models.Model):
     workspace = models.ForeignKey(
         Workspace,
         models.CASCADE,
+        null=True
     )
     certificate_template = models.ForeignKey(
         CertificateTemplate,

courses/certification/serializers.py

@@ -58,7 +58,9 @@ class CertificateDataSerializer(serializers.ModelSerializer):
             return None
 
     def get_contract(self, obj):
-        return SimpleWorkspaceSerializer(obj.workspace).data
+        if obj.workspace:
+            return SimpleWorkspaceSerializer(obj.workspace).data
+        return None
 
     def update(self, instance, validated_data):
         ct = dict(validated_data.pop('certificate_template'))

courses/certification/signals.py

 from django.db.models.signals import post_save
+from django.dispatch import receiver
 
 from base64 import urlsafe_b64encode as ub64
 from hashlib import sha1
 from time import time
 
-from courses.models import CourseStudent
-from courses.certification.models import CourseCertification
+from courses.models import Course, CourseStudent
+from courses.certification.models import CourseCertification, CertificateTemplate, CertificateData
 
 
 @receiver(post_save, sender=CourseStudent)
@@ -17,4 +18,15 @@ def course_student_created_or_updated(sender, created, instance, **kwargs):
                                         course=instance.course,
                                         type=CourseCertification.TYPES[0][0],
                                         is_valid=True, link_hash=link_hash.decode())
-        receipt.save()
\ No newline at end of file
+        receipt.save()
+
+
+@receiver(post_save, sender=Course)
+def course_created(sender, created, instance, **kwargs):
+
+    if created:
+        for type_ in CertificateData.TYPES:
+            ct = CertificateTemplate(course=instance)
+            ct.save()
+            cd = CertificateData(type=type_[0], certificate_template=ct)
+            cd.save()