Add '410 Gone' support for packages moved out of repositories

This allows us to do better than a generic 404 handler when we know a
package previously existed in a given repository, and should also make
things a bit nicer when getting sent in from a search engine to a page
that no longer exists.

Signed-off-by: Dan McGee <dan@archlinux.org>

3 files changed, 72 insertions, 5 deletions

diff --git a/packages/models.py b/packages/models.py
index 45ff3c08..18a62a3c 100644
--- a/packages/models.py
+++ b/packages/models.py
@@ -297,6 +297,9 @@ class Update(models.Model):
             return u'%d:%s-%s' % (self.new_epoch, self.new_pkgver, self.new_pkgrel)
         return u'%s-%s' % (self.new_pkgver, self.new_pkgrel)
 
+    def elsewhere(self):
+        return Package.objects.filter(pkgname=self.pkgname, arch=self.arch)
+
     def __unicode__(self):
         return u'%s of %s on %s' % (self.get_action_flag_display(),
                 self.pkgname, self.created)
diff --git a/packages/views/display.py b/packages/views/display.py
index dd57571a..5332dc13 100644
--- a/packages/views/display.py
+++ b/packages/views/display.py
@@ -1,18 +1,21 @@
+import datetime
 import json
 from string import Template
 from urllib import urlencode
 
 from django.http import HttpResponse, Http404
-from django.shortcuts import get_object_or_404, redirect
+from django.shortcuts import get_object_or_404, redirect, render
+from django.utils.timezone import now
 from django.views.generic.simple import direct_to_template
 from django.views.decorators.vary import vary_on_headers
 
 from main.models import Package, PackageFile, Arch, Repo
 from mirrors.utils import get_mirror_url_for_download
+from ..models import Update
 from ..utils import get_group_info, PackageJSONEncoder
 
 
-def split_package_details(request, name='', repo='', arch=''):
+def split_package_details(request, name, repo, arch):
     arch = get_object_or_404(Arch, name=arch)
     arches = [ arch ]
     arches.extend(Arch.objects.filter(agnostic=True))
@@ -21,10 +24,10 @@ def split_package_details(request, name='', repo='', arch=''):
             repo__testing=repo.testing, repo__staging=repo.staging,
             arch__in=arches).order_by('pkgname')
     if len(pkgs) == 0:
-        raise Http404
+        return None
     # we have packages, but ensure at least one is in the given repo
     if not any(True for pkg in pkgs if pkg.repo == repo):
-        raise Http404
+        return None
     context = {
         'list_title': 'Split Package Details',
         'name': name,
@@ -35,6 +38,30 @@ def split_package_details(request, name='', repo='', arch=''):
             context)
 
 
+CUTOFF = datetime.timedelta(days=60)
+
+
+def recently_removed_package(request, name, repo, arch, cutoff=CUTOFF):
+    '''We're just steps away from raising a 404, but check our packages update
+    table first to see if this package has existed in this repo before. If so,
+    we can show a 410 Gone page and point the requester in the right
+    direction.'''
+    arch = get_object_or_404(Arch, name=arch)
+    arches = [ arch ]
+    arches.extend(Arch.objects.filter(agnostic=True))
+    match = Update.objects.select_related('arch', 'repo').filter(
+            pkgname=name, repo__name__iexact=repo, arch__in=arches)
+    if cutoff is not None:
+        when = now() - cutoff
+        match = match.filter(created__gte=when)
+    try:
+        match = match.latest()
+        return render(request, 'packages/removed.html',
+                {'update': match, }, status=410)
+    except Update.DoesNotExist:
+        return None
+
+
 def details(request, name='', repo='', arch=''):
     if all([name, repo, arch]):
         try:
@@ -54,7 +81,16 @@ def details(request, name='', repo='', arch=''):
                     repo__name__iexact=repo, arch__agnostic=True)
                 if len(pkgs) == 1:
                     return redirect(pkgs[0], permanent=True)
-            return split_package_details(request, name, repo, arch)
+            # do we have a split package matching this criteria?
+            ret = split_package_details(request, name, repo, arch)
+            if ret is None:
+                # maybe we have a recently-removed package?
+                ret = recently_removed_package(request, name, repo, arch)
+            if ret is not None:
+                return ret
+            else:
+                # we've tried everything at this point, nothing to see
+                raise Http404
     else:
         pkg_data = [
             ('arch', arch.lower()),
diff --git a/templates/packages/removed.html b/templates/packages/removed.html
new file mode 100644
index 00000000..17b1f989
--- /dev/null
+++ b/templates/packages/removed.html
@@ -0,0 +1,28 @@
+{% extends "base.html" %}
+{% load url from future %}
+{% load package_extras %}
+
+{% block title %}Arch Linux - Not Available - {{ update.pkgname }} {{ update.old_version }} ({{ update.arch.name }}){% endblock %}
+{% block navbarclass %}anb-packages{% endblock %}
+
+{% block content %}
+<div id="pkg-gone" class="box">
+    <h2>{{ update.pkgname }} {{ update.old_version }} is no longer available</h2>
+
+    <p>{{ update.pkgname }} {{ update.old_version }} has been removed from the [{{ update.repo.name|lower }}] repository.</p>
+
+    {% with update.elsewhere as elsewhere %}{% if elsewhere %}
+    <p>However, this package is available in other repositories:</p>
+    <ul>
+        {% for pkg in elsewhere %}
+        <li>{% pkg_details_link pkg %} {{ pkg.full_version }} [{{ pkg.repo.name|lower }}] ({{ pkg.arch.name }})</li>
+        {% endfor %}
+    </ul>
+    {% else %}
+    <p>Unfortunately, this package cannot be found in any other repositories.
+    Try using the <a href="{% url 'packages-search' %}?name={{ update.pkgname|urlencode }}">package search page</a>,
+    or try <a href="https://aur.archlinux.org/packages.php?K={{ update.pkgname|urlencode }}">searching the AUR</a>
+    to see if the package can be found there.</p>
+    {% endif %}{% endwith %}
+</div>
+{% endblock %}