New Fingerprint model

backend/migrations/0002_fingerprint.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import backend.models
+from django.conf import settings
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('backend', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Fingerprint',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('fpr', backend.models.FingerprintField(unique=True, max_length=40, verbose_name='OpenPGP key fingerprint')),
+                ('user', models.ForeignKey(related_name='fprs', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'db_table': 'fingerprints',
+            },
+        ),
+    ]

backend/migrations/0003_auto_20150829_0905.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+from django.db import models, migrations
+import re
+
+def person_fpr_to_fingerprint(apps, schema_editor):
+    Person = apps.get_model("backend", "Person")
+    Fingerprint = apps.get_model("backend", "Fingerprint")
+    re_valid = re.compile(r"^[0-9A-Fa-f]+$")
+    for p in Person.objects.all():
+        # Skip empty fingerprints
+        if not p.fpr: continue
+        # Skip invalid fingerprints (match by hex regexp)
+        if not re_valid.match(p.fpr): continue
+        # Create a corresponding Fingerprint object
+        Fingerprint.objects.create(user=p, fpr=p.fpr)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('backend', '0002_fingerprint'),
+    ]
+
+    operations = [
+        migrations.RunPython(person_fpr_to_fingerprint),
+    ]

backend/models.py

@@ -80,18 +80,23 @@ class CharNullField(models.CharField):
            return value
 
 class FingerprintField(models.CharField):
-    description = "CharField that stores NULL but returns '', also strip spaces and upper storing"
+    description = "CharField that holds hex digits, without spaces, in uppercase"
+    re_spaces = re.compile(r"\s+")
+    re_invalid = re.compile(r"[^0-9A-Fa-f]+")
 
     def _clean_fingerprint(self, value):
-        # if the db has a NULL, convert it into the Django-friendly '' string
-        if not value: return None
+        # Refuse all non-strings
         if not isinstance(value, basestring): return None
-        value = value.strip()
+        # Remove spaces
+        value = self.re_spaces.sub("", value)
+        # Convert empty strings to None
         if not value: return None
-        if value.startswith("FIXME"): return re.sub("[^a-zA-Z0-9_-]+", "-", value)[:40]
-        value = value.replace(' ', '').upper()
-        if not re.match(r"^[0-9A-F]{32,40}$", value): return None
-        return value
+        # Refuse strings with non-hex characters
+        if self.re_invalid.search(value): return None
+        # Refuse hex strings whose length does not match a fingerprint
+        if len(value) != 32 and len(value) != 40: return None
+        # Uppercase the result
+        return value.upper()
 
     ## not really useful, because in Person this is blank=True which not cleaned / validated
     def to_python(self, value):
@@ -99,22 +104,18 @@ class FingerprintField(models.CharField):
         Converts a value from the database to a python object
         """
         value = super(FingerprintField, self).to_python(value)
-        value = self._clean_fingerprint(value)
-        if not value: return ""
-        return value
+        return self._clean_fingerprint(value)
 
     def get_prep_value(self, value):
         """
         Converts a value from python to the DB
         """
         value = super(FingerprintField, self).get_prep_value(value)
-        value = self._clean_fingerprint(value)
-        if not value: return None
-        return value
+        return self._clean_fingerprint(value)
 
     def formfield(self, **kwargs):
-        # we want bypass our parent to fix "maxlength" attribute in widget
-        # fingerprint with space are 50 chars to allow easy cut-and-paste
+        # bypass our parent to fix "maxlength" attribute in widget: fingerprint
+        # with spaces are 50 chars to allow easy copy-and-paste
         if 'max_length' not in kwargs:
             kwargs.update({'max_length': 50})
         return super(FingerprintField, self).formfield(**kwargs)
@@ -758,6 +759,18 @@ class Person(PermissionsMixin, models.Model):
         raise Http404
 
 
+class Fingerprint(models.Model):
+    """
+    A fingerprint for a person
+    """
+    class Meta:
+        db_table = "fingerprints"
+
+    user = models.ForeignKey(Person, related_name="fprs")
+    # OpenPGP fingerprint, NULL until one has been provided
+    fpr = FingerprintField("OpenPGP key fingerprint", max_length=40, unique=True)
+
+
 class PersonAuditLog(models.Model):
     person = models.ForeignKey(Person, related_name="audit_log")
     logdate = models.DateTimeField(null=False, auto_now_add=True)