add initial_seed to access changes

Can be used to fix the initial seed for an exam for certain students.

fixes #314

Author: christianp

numbas_lti/forms.py

@@ -67,6 +67,7 @@ class Meta:
             'require_lockdown_app',
             'lockdown_app_password',
             'seb_settings',
+            'initial_seed',
         ]
         widgets = {
             'description': forms.TextInput(),

numbas_lti/migrations/0098_accesschange_initial_seed.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.0.7 on 2024-12-19 09:19
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('numbas_lti', '0097_userscorereported'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='accesschange',
+            name='initial_seed',
+            field=models.CharField(blank=True, default='', max_length=20, verbose_name='Initial seed for the random number generator'),
+        ),
+    ]

numbas_lti/models.py

@@ -971,6 +971,8 @@ class AccessChange(models.Model):
     lockdown_app_password = models.CharField(max_length=30, blank=True, verbose_name=_('Password for the Numbas lockdown app'))
     seb_settings = models.ForeignKey(SebSettings, blank=True, null=True, on_delete=models.SET_NULL, related_name='access_changes')
 
+    initial_seed = models.CharField(max_length=20, default='', blank=True, verbose_name = _('Initial seed for the random number generator'))
+
     users = models.ManyToManyField(User, blank=True, related_name='access_changes')
 
     objects = AccessChangeManager()
@@ -1172,6 +1174,13 @@ def scorm_cmi(self, include_remarked_elements=True, at_time=None):
             'cmi.success_status': '',
             'cmi.completion_status': self.completion_status,
         }
+
+        changes = self.resource.access_changes.for_user(self.user)
+
+        for change in changes:
+            if change.initial_seed:
+                scorm_cmi['numbas.initial_seed'] = change.initial_seed
+
         scorm_cmi = {k: {'value':v,'time':self.start_time.timestamp()} for k,v in scorm_cmi.items()}
 
         # TODO only fetch the latest values of elements from the DB, somehow

numbas_lti/templates/numbas_lti/management/access_change/edit.html

@@ -76,9 +76,9 @@ <h1>{% if create %}{% translate "Create an access change" %}{% else %}{% transla
                 </p>
             </fieldset>
 
-            {% if resource.exam.has_duration %}
             <fieldset>
-                <legend>{% translate "Exam duration" %}</legend>
+                <legend>{% translate "Exam settings" %}</legend>
+                {% if resource.exam.has_duration %}
                 <p>
                     <label for="{{form.extend_duration.id_for_label}}">{{form.extend_duration.label}}</label>
                     {{form.extend_duration}}
@@ -91,8 +91,16 @@ <h1>{% if create %}{% translate "Create an access change" %}{% else %}{% transla
                 <p class="help-block">
                     {% blocktranslate %}Change the length of time the student has to complete an attempt after starting it.{% endblocktranslate %}
                 </p>
+                {% endif %}
+
+                <p>
+                    {{form.initial_seed.label_tag}}
+                    {{form.initial_seed}}
+                </p>
+                <p class="help-block">
+                    {% blocktranslate %}Leave blank to use a different seed for each attempt.{% endblocktranslate %}
+                </p>
             </fieldset>
-            {% endif %}
             <fieldset>
                 <legend>{% translate "Number of attempts" %}</legend>