Re ic-labs#284 WIP URL shortener

icekit/admin_tools/mixins.py

@@ -10,6 +10,7 @@
 
 from icekit.admin_tools.previews import RawIdPreviewAdminMixin
 from icekit.admin_tools.utils import admin_link
+from icekit.redirects.admin import RedirectInline
 from icekit.utils.attributes import resolve
 
 from django.utils.translation import ugettext_lazy as _
@@ -70,6 +71,9 @@ class HeroMixinAdmin(RawIdPreviewAdminMixin):
 
 
 class ListableMixinAdmin(admin.ModelAdmin):
+
+    # inlines = [RedirectInline]
+
     FIELDSETS = (
         ('Advanced listing options', {
             'classes': ('collapse',),

icekit/project/settings/_base.py

@@ -343,10 +343,10 @@
 
 # Requires: django.contrib.sites
 
-INSTALLED_APPS += ('django.contrib.redirects', )
+INSTALLED_APPS += ('icekit.redirects', )
 
 MIDDLEWARE_CLASSES += (
-    'django.contrib.redirects.middleware.RedirectFallbackMiddleware',
+    'icekit.redirects.middleware.RedirectFallbackMiddleware',
 )
 
 # DJANGO SITES ################################################################

icekit/project/settings/calculated.py

@@ -77,7 +77,7 @@
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.cache.FetchFromCacheMiddleware',
     'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
-    'django.contrib.redirects.middleware.RedirectFallbackMiddleware',
+    'icekit.redirects.middleware.RedirectFallbackMiddleware',
 ])
 
 # Get the secret key from a file that should never be committed to version

icekit/redirects/__init__.py

@@ -0,0 +1 @@
+default_app_config = '%s.apps.AppConfig' % __name__

icekit/redirects/admin.py

@@ -0,0 +1,19 @@
+from django.contrib import admin
+from django.contrib.contenttypes.admin import GenericTabularInline
+
+from .models import Redirect
+
+class RedirectAdmin(admin.ModelAdmin):
+    """
+    A copy from django.contrib.redirects
+    """
+    list_display = ('old_path', 'new_path')
+    list_filter = ('site',)
+    search_fields = ('old_path', 'new_path')
+    radio_fields = {'site': admin.VERTICAL}
+
+admin.site.register(Redirect, RedirectAdmin)
+
+
+class RedirectInline(GenericTabularInline):
+    model = Redirect

icekit/redirects/apps.py

@@ -0,0 +1,7 @@
+from django.apps import AppConfig
+from django.utils.translation import ugettext_lazy as _
+
+class AppConfig(AppConfig):
+    name = '.'.join(__name__.split('.')[:-1])
+    label = 'redirects'
+    verbose_name = _("Redirects")

icekit/redirects/middleware.py

@@ -0,0 +1,55 @@
+"""
+A nearly exact copy from django.contrib.redirects
+"""
+
+from __future__ import unicode_literals
+
+from django import http
+from django.apps import apps
+from django.conf import settings
+from .models import Redirect
+from django.contrib.sites.shortcuts import get_current_site
+from django.core.exceptions import ImproperlyConfigured
+
+
+class RedirectFallbackMiddleware(object):
+
+    # Defined as class-level attributes to be subclassing-friendly.
+    response_gone_class = http.HttpResponseGone
+    response_redirect_class = http.HttpResponsePermanentRedirect
+
+    def __init__(self):
+        if not apps.is_installed('django.contrib.sites'):
+            raise ImproperlyConfigured(
+                "You cannot use RedirectFallbackMiddleware when "
+                "django.contrib.sites is not installed."
+            )
+
+    def process_response(self, request, response):
+        # No need to check for a redirect for non-404 responses.
+        if response.status_code != 404:
+            return response
+
+        full_path = request.get_full_path()
+        current_site = get_current_site(request)
+
+        r = None
+        try:
+            r = Redirect.objects.get(site=current_site, old_path=full_path)
+        except Redirect.DoesNotExist:
+            pass
+        if settings.APPEND_SLASH and not request.path.endswith('/'):
+            # Try appending a trailing slash.
+            path_len = len(request.path)
+            full_path = full_path[:path_len] + '/' + full_path[path_len:]
+            try:
+                r = Redirect.objects.get(site=current_site, old_path=full_path)
+            except Redirect.DoesNotExist:
+                pass
+        if r is not None:
+            if r.new_path == '':
+                return self.response_gone_class()
+            return self.response_redirect_class(r.new_path)
+
+        # No redirect was found. Return the response.
+        return response

icekit/redirects/migrations/0001_initial.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sites', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Redirect',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('site', models.ForeignKey(to='sites.Site', to_field='id')),
+                ('old_path', models.CharField(help_text="This should be an absolute path, excluding the domain name. Example: '/events/search/'.", max_length=200, verbose_name='redirect from', db_index=True)),
+                ('new_path', models.CharField(help_text="This can be either an absolute path (as above) or a full URL starting with 'http://'.", max_length=200, verbose_name='redirect to', blank=True)),
+            ],
+            options={
+                'ordering': ('old_path',),
+                'unique_together': set([('site', 'old_path')]),
+                'db_table': 'django_redirect',
+                'verbose_name': 'redirect',
+                'verbose_name_plural': 'redirects',
+            },
+            bases=(models.Model,),
+        ),
+    ]

icekit/redirects/migrations/0002_auto_20170815_1519.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('contenttypes', '0002_remove_content_type_name'),
+        ('redirects', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='redirect',
+            name='content_type',
+            field=models.ForeignKey(to='contenttypes.ContentType', null=True, blank=True),
+        ),
+        migrations.AddField(
+            model_name='redirect',
+            name='object_id',
+            field=models.PositiveIntegerField(blank=True, null=True),
+        ),
+        migrations.AlterField(
+            model_name='redirect',
+            name='new_path',
+            field=models.CharField(blank=True, verbose_name='URL override', max_length=200, help_text="This can be either an absolute path (as above) or a full URL. Example: '/events/search/?q=kids'."),
+        ),
+        migrations.AlterField(
+            model_name='redirect',
+            name='old_path',
+            field=models.CharField(db_index=True, blank=True, verbose_name='redirect from', max_length=200, help_text="This can be any unused path, excluding the domain name. Example: '/kids'. A short URL will be generated if this is left blank."),
+        ),
+        migrations.AlterField(
+            model_name='redirect',
+            name='site',
+            field=models.ForeignKey(to='sites.Site', default=1),
+        ),
+    ]

icekit/redirects/models.py

@@ -0,0 +1,61 @@
+from random import randint
+
+from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.models import ContentType
+from django.contrib.sites.models import Site
+from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
+from django.utils.translation import ugettext_lazy as _
+from icekit.fields import ICEkitURLField
+
+from .utils import short_code_from_id
+from django.conf import settings
+
+
+@python_2_unicode_compatible
+class Redirect(models.Model):
+    """
+    A simple model, database-superset of django.contrib.redirect, for sending one URL to another.
+
+    We customise this model to generate short URLs if old_path isn't given, and to ensure slashes.
+    """
+
+    # redirect fields
+    site = models.ForeignKey(Site, default=settings.SITE_ID)
+    old_path = models.CharField(_('redirect from'), max_length=200, db_index=True, blank=True,
+        help_text=_("This can be any unused path, excluding the domain name. Example: '/kids'. "
+                    "A short URL will be generated if this is left blank."))
+    # this contrib.redirect field is now used as an 'override'.
+    new_path = models.CharField(_('URL override'), max_length=200, blank=True,
+        help_text=_("This can be either an absolute path (as above) or a full URL. Example: '/events/search/?q=kids'."))
+
+
+    # GFK to a piece of content
+    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE, null=True, blank=True)
+    object_id = models.PositiveIntegerField(null=True, blank=True)
+    content_object = GenericForeignKey('content_type', 'object_id')
+
+
+    class Meta:
+        verbose_name = _('redirect')
+        verbose_name_plural = _('redirects')
+        db_table = 'django_redirect'
+        unique_together = (('site', 'old_path'),)
+        ordering = ('old_path',)
+
+    def __str__(self):
+        return "%s ---> %s" % (self.old_path, self.new_path)
+
+    def save(self, *args, **kwargs):
+        if not self.old_path:
+            # we'll need to generate a short code. We want to use the DB ID. If we don't already have one, we
+            # fake a value, save, and use that ID to generate the code.
+            if not self.id:
+                self.old_path = "__TEMPPATH_%s__" % randint(0,32000)
+                super(Redirect, self).save(*args, **kwargs)
+            self.old_path = short_code_from_id(self.id)
+
+        if not self.old_path.startswith('/'):
+            self.old_path = "/%s" % self.old_path
+
+        super(Redirect, self).save(*args, **kwargs)

icekit/redirects/utils.py

@@ -0,0 +1,41 @@
+import string
+
+ALPHABET = string.digits + string.lowercase
+
+def base36encode(number):
+    """Converts a positive integer to a base36 string."""
+    if not isinstance(number, (int, long)):
+        raise TypeError('`number` must be an integer')
+
+    base36 = ''
+
+    if 0 <= number < len(ALPHABET):
+        return ALPHABET[number]
+
+    while number != 0:
+        number, i = divmod(number, len(ALPHABET))
+        base36 = ALPHABET[i] + base36
+
+    return base36
+
+
+def base36decode(number):
+    return int(number, len(ALPHABET))
+
+
+def short_code_from_id(integer, min_length=2):
+    """
+    :param input: a positive integer (ID) representing the URL to be shortened.
+    :return: a string comprising the letters 0-9 and a-z that maps to that ID
+
+    Assuming a DB ID is passed, the result should be unique.
+
+    We will also ensure that the returned string is at least n characters long, so that the single-character namespace
+    is reserved for future. We do this by adding len(ALPHABET) ^ min_length to the integer.
+
+    It's not necessary that this function be reversible - as we're using a database lookup - just unique. (If we needed
+    reversibility we'd either need to fix min_length or would need to encode it in the output.)
+    """
+
+    minimum_number = len(ALPHABET) ** (min_length - 1)
+    return base36encode(integer + minimum_number)