add LocationRedirect and fallback slug for locations

src/c3nav/mapdata/api.py

@@ -2,6 +2,7 @@ import mimetypes
 from itertools import chain
 
 from django.http import HttpResponse
+from django.shortcuts import redirect
 from django.utils.translation import ugettext_lazy as _
 from rest_framework.decorators import detail_route, list_route
 from rest_framework.exceptions import NotFound, ValidationError
@@ -13,7 +14,7 @@ from c3nav.access.apply import filter_queryset_by_access
 from c3nav.mapdata.models import Building, Door, Hole, LocationGroup, Source, Space
 from c3nav.mapdata.models.geometry.section import SECTION_MODELS
 from c3nav.mapdata.models.geometry.space import SPACE_MODELS, Area, LineObstacle, Obstacle, Point, Stair
-from c3nav.mapdata.models.locations import LOCATION_MODELS, LocationSlug
+from c3nav.mapdata.models.locations import LOCATION_MODELS, Location, LocationRedirect, LocationSlug
 from c3nav.mapdata.models.section import Section
 from c3nav.mapdata.serializers.main import SourceSerializer
 from c3nav.mapdata.utils.cache import CachedReadOnlyViewSetMixin
@@ -137,11 +138,19 @@ class LocationGroupViewSet(MapdataViewSet):
 
 
 class LocationViewSet(RetrieveModelMixin, GenericViewSet):
+    """ Add ?show_redirect=1 to suppress redirects and show them as JSON. """
     queryset = LocationSlug.objects.all()
     lookup_field = 'slug'
 
-    def retrieve(self, request, *args, **kwargs):
+    def retrieve(self, request, slug=None, *args, **kwargs):
-        return Response(self.get_object().get_child().serialize(include_type=True))
+        result = Location.get_by_slug(slug, self.get_queryset())
+        if result is None:
+            raise NotFound
+        if isinstance(result, LocationRedirect):
+            if 'show_redirects' in request.GET:
+                return Response(result.serialize(include_type=True))
+            return redirect('../'+result.target.slug)  # todo: why does redirect/reverse not work here?
+        return Response(result.get_child().serialize(include_type=True))
 
     @list_route(methods=['get'])
     def types(self, request):

src/c3nav/mapdata/migrations/0002_locationredirect.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-05-11 19:59
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('mapdata', '0001_squashed_refactor_2017'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='LocationRedirect',
+            fields=[
+                ('locationslug_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, related_name='redirect', serialize=False, to='mapdata.LocationSlug')),
+                ('target', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='redirects', to='mapdata.LocationSlug', verbose_name='target')),
+            ],
+            options={
+                'default_related_name': 'redirect',
+            },
+            bases=('mapdata.locationslug',),
+        ),
+    ]

src/c3nav/mapdata/models/base.py

@@ -5,9 +5,7 @@ from django.db import models
 EDITOR_FORM_MODELS = OrderedDict()
 
 
-class EditorFormMixin(models.Model):
+class SerializableMixin(models.Model):
-    EditorForm = None
-
     class Meta:
         abstract = True
 
@@ -29,3 +27,10 @@ class EditorFormMixin(models.Model):
             result['type'] = self.__class__.__name__.lower()
         result['id'] = self.id
         return result
+
+
+class EditorFormMixin(SerializableMixin, models.Model):
+    EditorForm = None
+
+    class Meta:
+        abstract = True

src/c3nav/mapdata/models/locations.py

@@ -1,4 +1,5 @@
 import numpy as np
+from django.apps import apps
 from django.core.cache import cache
 from django.db import models
 from django.utils.functional import cached_property
@@ -7,17 +8,25 @@ from django.utils.translation import get_language, ungettext_lazy
 
 from c3nav.mapdata.fields import JSONField
 from c3nav.mapdata.lastupdate import get_last_mapdata_update
-from c3nav.mapdata.models.base import EditorFormMixin
+from c3nav.mapdata.models.base import EditorFormMixin, SerializableMixin
 
 LOCATION_MODELS = []
 
 
-class LocationSlug(models.Model):
+class LocationSlug(SerializableMixin, models.Model):
+    LOCATION_TYPE_CODES = {
+        'Section': 'se',
+        'Space': 'sp',
+        'Area': 'a',
+        'Point': 'p',
+        'LocationGroup': 'g'
+    }
+    LOCATION_TYPE_BY_CODE = {code: model_name for model_name, code in LOCATION_TYPE_CODES.items()}
     slug = models.SlugField(_('name'), unique=True, null=True, max_length=50)
 
     def get_child(self):
         # todo: cache this
-        for model in LOCATION_MODELS:
+        for model in LOCATION_MODELS+[LocationRedirect]:
             try:
                 return getattr(self, model._meta.default_related_name)
             except AttributeError:
@@ -47,7 +56,7 @@ class Location(LocationSlug, EditorFormMixin, models.Model):
 
     def _serialize(self, **kwargs):
         result = super()._serialize(**kwargs)
-        result['slug'] = self.slug
+        result['slug'] = self.get_slug()
         result['titles'] = self.titles
         result['can_search'] = self.can_search
         result['can_describe'] = self.can_search
@@ -55,6 +64,37 @@ class Location(LocationSlug, EditorFormMixin, models.Model):
         result['public'] = self.public
         return result
 
+    def get_slug(self):
+        if self.slug is None:
+            code = self.LOCATION_TYPE_CODES.get(self.__class__.__name__)
+            if code is not None:
+                return code+':'+str(self.id)
+        return self.slug
+
+    @classmethod
+    def get_by_slug(cls, slug, queryset=None):
+        if queryset is None:
+            queryset = LocationSlug.objects.all()
+
+        if ':' in slug:
+            code, pk = slug.split(':', 1)
+            model_name = cls.LOCATION_TYPE_BY_CODE.get(code)
+            if model_name is None or not pk.isdigit():
+                return None
+
+            model = apps.get_model('mapdata', model_name)
+            try:
+                location = model.objects.get(pk=pk)
+            except model.DoesNotExist:
+                return None
+
+            if location.slug is not None:
+                return LocationRedirect(slug=slug, target=location)
+
+            return location
+
+        return queryset.filter(slug=slug).first()
+
     @property
     def title(self):
         if not hasattr(self, 'titles'):
@@ -135,6 +175,24 @@ class LocationGroup(Location, EditorFormMixin, models.Model):
         return result
 
 
+class LocationRedirect(LocationSlug):
+    target = models.ForeignKey(LocationSlug, verbose_name=_('target'), related_name='redirects')
+
+    def _serialize(self, with_type=True, **kwargs):
+        result = super()._serialize(with_type=with_type, **kwargs)
+        if type(self.target) == LocationSlug:
+            result['target'] = self.target.get_child().slug
+        else:
+            result['target'] = self.target.slug
+        if with_type:
+            result['type'] = 'redirect'
+        result.pop('id')
+        return result
+
+    class Meta:
+        default_related_name = 'redirect'
+
+
 class PointLocation:
     def __init__(self, section: 'Section', x: int, y: int, request):
         self.section = section