Initial work on categorisation rewrite.

Remove relation between blog and categories / tags
Soft-resolve duplicates on query via URLSegment
Remove and simplify tag / category management
Code quality cleanup

src/Admin/GridFieldCategorisationConfig.php

@@ -4,6 +4,7 @@ namespace SilverStripe\Blog\Admin;
 
 use SilverStripe\Blog\Forms\GridField\GridFieldAddByDBField;
 use SilverStripe\Blog\Model\CategorisationObject;
+use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Forms\GridField\GridFieldAddNewButton;
 use SilverStripe\Forms\GridField\GridFieldConfig_RecordEditor;
 use SilverStripe\Forms\GridField\GridFieldDataColumns;
@@ -12,13 +13,14 @@ use SilverStripe\ORM\SS_List;
 class GridFieldCategorisationConfig extends GridFieldConfig_RecordEditor
 {
     /**
-     * @param int $itemsPerPage
+     * @param int           $itemsPerPage
      * @param array|SS_List $mergeRecords
-     * @param string $parentType
+     * @param string        $parentType
-     * @param string $parentMethod
+     * @param string        $parentMethod
-     * @param string $childMethod
+     * @param string        $childMethod
+     * @param SiteTree      $parent
      */
-    public function __construct($itemsPerPage, $mergeRecords, $parentType, $parentMethod, $childMethod)
+    public function __construct($itemsPerPage, $mergeRecords, $parentType, $parentMethod, $childMethod, $parent)
     {
         parent::__construct($itemsPerPage);
 
@@ -39,31 +41,24 @@ class GridFieldCategorisationConfig extends GridFieldConfig_RecordEditor
 
         $columns->setFieldFormatting(
             [
-                'BlogPostsCount' => function ($value, CategorisationObject $item) {
+                'BlogPostsCount'    => function ($value, CategorisationObject $item) use ($parent) {
+                    return $item
+                        ->BlogPosts()
+                        ->filter(['ParentID' => $parent->ID])
+                        ->Count();
+                },
+                'BlogPostsAllCount' => function ($value, CategorisationObject $item) {
                     return $item->BlogPosts()->Count();
-                }
+                },
             ]
         );
-
-        $this->changeColumnOrder();
-    }
-
-    /**
-     * Reorders GridField columns so that Actions is last.
-     */
-    protected function changeColumnOrder()
-    {
-        /**
-         * @var GridFieldDataColumns $columns
-         */
-        $columns = $this->getComponentByType(GridFieldDataColumns::class);
-
         $columns->setDisplayFields(
             [
-                'Title'          => _t(__CLASS__ . '.Title', 'Title'),
+                'Title'             => _t(__CLASS__ . '.Title', 'Title'),
-                'BlogPostsCount' => _t(__CLASS__ . '.Posts', 'Posts'),
+                'BlogPostsCount'    => _t(__CLASS__ . '.PostsThisBlog', 'Posts (This Blog)'),
-                'MergeAction'    => 'MergeAction',
+                'BlogPostsAllCount' => _t(__CLASS__ . '.PostsAllBlogs', 'Posts (All Blogs)'),
-                'Actions'        => 'Actions'
+                'MergeAction'       => 'MergeAction',
+                'Actions'           => 'Actions'
             ]
         );
     }

src/Model/Blog.php

@@ -2,10 +2,10 @@
 
 namespace SilverStripe\Blog\Model;
 
+use Exception;
 use Page;
 use SilverStripe\Blog\Admin\GridFieldCategorisationConfig;
 use SilverStripe\Blog\Forms\GridField\GridFieldConfigBlogPost;
-use SilverStripe\CMS\Controllers\RootURLController;
 use SilverStripe\Control\Controller;
 use SilverStripe\Core\Convert;
 use SilverStripe\Forms\FieldList;
@@ -14,13 +14,15 @@ use SilverStripe\Forms\GridField\GridFieldConfig;
 use SilverStripe\Forms\ListboxField;
 use SilverStripe\Forms\LiteralField;
 use SilverStripe\Forms\NumericField;
+use SilverStripe\Forms\Tab;
+use SilverStripe\Forms\TabSet;
 use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DB;
-use SilverStripe\ORM\HasManyList;
 use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\UnsavedRelationList;
+use SilverStripe\ORM\ValidationException;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
@@ -31,8 +33,7 @@ use SilverStripe\View\Requirements;
 /**
  * Blog Holder
  *
- * @method HasManyList Tags() List of tags in this blog
+ * @property int $PostsPerPage
- * @method HasManyList Categories() List of categories in this blog
  * @method ManyManyList Editors() List of editors
  * @method ManyManyList Writers() List of writers
  * @method ManyManyList Contributors() List of contributors
@@ -88,20 +89,12 @@ class Blog extends Page implements PermissionProvider
         'PostsPerPage' => 'Int',
     ];
 
-    /**
-     * @var array
-     */
-    private static $has_many = [
-        'Tags' => BlogTag::class,
-        'Categories' => BlogCategory::class,
-    ];
-
     /**
      * @var array
      */
     private static $many_many = [
-        'Editors' => Member::class,
+        'Editors'      => Member::class,
-        'Writers' => Member::class,
+        'Writers'      => Member::class,
         'Contributors' => Member::class,
     ];
 
@@ -134,6 +127,52 @@ class Blog extends Page implements PermissionProvider
 
     private static $icon_class = 'font-icon-p-posts';
 
+    /**
+     * Gets the list of all tags attached to this blog
+     *
+     * @param bool $hideEmpty Set to false to include tags without posts
+     * @return DataList|BlogTag[]
+     */
+    public function Tags($hideEmpty = true)
+    {
+        $tags = BlogTag::get();
+        if ($this->ID) {
+            $tags->setDataQueryParam('BlogID', $this->ID);
+
+            // Conditionally hide empty tags
+            if ($hideEmpty) {
+                $tags = $tags->filter([
+                    'BlogPosts.ParentID' => $this->ID,
+                ]);
+            }
+        }
+        $this->extend('updateBlogTags', $tags);
+        return $tags;
+    }
+
+    /**
+     * Gets the list of all categories attached to this blog
+     *
+     * @param bool $hideEmpty Set to false to include categories without posts
+     * @return DataList|BlogCategory[]
+     */
+    public function Categories($hideEmpty = true)
+    {
+        $tags = BlogCategory::get();
+        if ($this->ID) {
+            $tags->setDataQueryParam('BlogID', $this->ID);
+
+            // Conditionally hide empty categories
+            if ($hideEmpty) {
+                $tags = $tags->filter([
+                    'BlogPosts.ParentID' => $this->ID,
+                ]);
+            }
+        }
+        $this->extend('updateBlogCategories', $tags);
+        return $tags;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -141,7 +180,7 @@ class Blog extends Page implements PermissionProvider
     {
         $this->addCMSRequirements();
 
-        $this->beforeUpdateCMSFields(function ($fields) {
+        $this->beforeUpdateCMSFields(function (FieldList $fields) {
             if (!$this->canEdit()) {
                 return;
             }
@@ -149,43 +188,47 @@ class Blog extends Page implements PermissionProvider
             $categories = GridField::create(
                 'Categories',
                 _t(__CLASS__ . '.Categories', 'Categories'),
-                $this->Categories(),
+                $this->Categories(false),
                 GridFieldCategorisationConfig::create(
                     15,
-                    $this->Categories()->sort('Title'),
+                    $this->Categories(false)->sort('Title'),
                     BlogCategory::class,
                     'Categories',
-                    'BlogPosts'
+                    'BlogPosts',
+                    $this
                 )
             );
 
             $tags = GridField::create(
                 'Tags',
                 _t(__CLASS__ . '.Tags', 'Tags'),
-                $this->Tags(),
+                $this->Tags(false),
                 GridFieldCategorisationConfig::create(
                     15,
-                    $this->Tags()->sort('Title'),
+                    $this->Tags(false)->sort('Title'),
                     BlogTag::class,
                     'Tags',
-                    'BlogPosts'
+                    'BlogPosts',
+                    $this
                 )
             );
 
-            /**
+            $fields->addFieldToTab(
-             * @var FieldList $fields
+                'Root',
-             */
+                TabSet::create('Categorisation', _t(__CLASS__ . '.Categorisation', 'Categorisation'))
-            $fields->addFieldsToTab(
+                    ->addExtraClass('blog-cms-categorisation')
+            );
+            $fields->addFieldToTab(
                 'Root.Categorisation',
-                [
+                Tab::create('Categories', _t(__CLASS__ . '.Categories', 'Categories'))
-                    $categories,
+            );
-                    $tags
+            $fields->addFieldToTab(
-                ]
+                'Root.Categorisation',
+                Tab::create('Tags', _t(__CLASS__ . '.Tags', 'Tags'))
             );
 
-            $fields->fieldByName('Root.Categorisation')
+            $fields->addFieldToTab('Root.Categorisation.Categories', $categories);
-                ->addExtraClass('blog-cms-categorisation')
+            $fields->addFieldToTab('Root.Categorisation.Tags', $tags);
-                ->setTitle(_t(__CLASS__ . '.Categorisation', 'Categorisation'));
         });
 
         return parent::getCMSFields();
@@ -199,6 +242,7 @@ class Blog extends Page implements PermissionProvider
         Requirements::css('silverstripe/blog:client/dist/styles/main.css');
         Requirements::javascript('silverstripe/blog:client/dist/js/main.bundle.js');
     }
+
     /**
      * {@inheritdoc}
      */
@@ -249,7 +293,7 @@ class Blog extends Page implements PermissionProvider
     /**
      * Determine if the given member belongs to the given relation.
      *
-     * @param Member $member
+     * @param Member   $member
      * @param DataList $relation
      *
      * @return bool
@@ -527,7 +571,7 @@ class Blog extends Page implements PermissionProvider
     /**
      * Returns BlogPosts for a given date period.
      *
-     * @param int $year
+     * @param int      $year
      * @param null|int $month
      * @param null|int $day
      *
@@ -592,13 +636,7 @@ class Blog extends Page implements PermissionProvider
      */
     public function ProfileLink($urlSegment)
     {
-        $baseLink = $this->Link();
+        return Controller::join_links($this->Link('Profile'), $urlSegment);
-        if ($baseLink === '/') {
-            // Handle homepage blogs
-            $baseLink = RootURLController::get_homepage_link();
-        }
-
-        return Controller::join_links($baseLink, 'profile', $urlSegment);
     }
 
     /**
@@ -628,22 +666,22 @@ class Blog extends Page implements PermissionProvider
     {
         return [
             Blog::MANAGE_USERS => [
-                'name' => _t(
+                'name'     => _t(
                     __CLASS__ . '.PERMISSION_MANAGE_USERS_DESCRIPTION',
                     'Manage users for individual blogs'
                 ),
-                'help' => _t(
+                'help'     => _t(
                     __CLASS__ . '.PERMISSION_MANAGE_USERS_HELP',
                     'Allow assignment of Editors, Writers, or Contributors to blogs'
                 ),
                 'category' => _t(__CLASS__ . '.PERMISSIONS_CATEGORY', 'Blog permissions'),
-                'sort' => 100
+                'sort'     => 100
             ]
         ];
     }
 
     /**
-     * {@inheritdoc}
+     * @throws ValidationException
      */
     protected function onBeforeWrite()
     {
@@ -653,6 +691,9 @@ class Blog extends Page implements PermissionProvider
 
     /**
      * Assign users as necessary to the blog group.
+     *
+     * @throws ValidationException
+     * @throws Exception
      */
     protected function assignGroup()
     {
@@ -665,6 +706,7 @@ class Blog extends Page implements PermissionProvider
         // Must check if the method exists or else an error occurs when changing page type
         if ($this->hasMethod('Editors')) {
             foreach ([$this->Editors(), $this->Writers(), $this->Contributors()] as $levels) {
+                /** @var Member $user */
                 foreach ($levels as $user) {
                     if (!$user->inGroup($group)) {
                         $user->Groups()->add($group);
@@ -678,13 +720,14 @@ class Blog extends Page implements PermissionProvider
      * Gets or creates the group used to assign CMS access.
      *
      * @return Group
+     * @throws ValidationException
      */
     protected function getUserGroup()
     {
         $code = $this->config()->get('grant_user_group');
 
+        /** @var Group $group */
         $group = Group::get()->filter('Code', $code)->first();
-
         if ($group) {
             return $group;
         }

src/Model/BlogCategory.php

@@ -3,16 +3,14 @@
 namespace SilverStripe\Blog\Model;
 
 use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\ManyManyList;
 
 /**
  * A blog category for generalising blog posts.
  *
-*
+ * @method ManyManyList|BlogPost[] BlogPosts()
- * @method Blog Blog()
- *
  * @property string $Title
  * @property string $URLSegment
- * @property int $BlogID
  */
 class BlogCategory extends DataObject implements CategorisationObject
 {
@@ -44,8 +42,8 @@ class BlogCategory extends DataObject implements CategorisationObject
     /**
      * @var array
      */
-    private static $has_one = [
+    private static $indexes = [
-        'Blog' => Blog::class,
+        'URLSegment' => true,
     ];
 
     /**

src/Model/BlogController.php

@@ -6,14 +6,17 @@ use PageController;
 use SilverStripe\Control\Director;
 use SilverStripe\Control\HTTPResponse_Exception;
 use SilverStripe\Control\RSS\RSSFeed;
-use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\FieldType\DBDatetime;
+use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\ORM\PaginatedList;
+use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Member;
 use SilverStripe\View\Parsers\URLSegmentFilter;
-use SilverStripe\Control\HTTPRequest;
 
+/**
+ * @method Blog data()
+ */
 class BlogController extends PageController
 {
     /**
@@ -31,17 +34,17 @@ class BlogController extends PageController
      * @var array
      */
     private static $url_handlers = [
-        'tag/$Tag!/$Rss' => 'tag',
+        'tag/$Tag!/$Rss'             => 'tag',
-        'category/$Category!/$Rss' => 'category',
+        'category/$Category!/$Rss'   => 'category',
         'archive/$Year!/$Month/$Day' => 'archive',
-        'profile/$URLSegment!' => 'profile'
+        'profile/$Profile!'          => 'profile'
     ];
 
     /**
      * @var array
      */
     private static $casting = [
-        'MetaTitle' => 'Text',
+        'MetaTitle'         => 'Text',
         'FilterDescription' => 'Text'
     ];
 
@@ -60,27 +63,11 @@ class BlogController extends PageController
      */
     protected $blogPosts;
 
-    /**
-     * @return string
-     */
-    public function index(HTTPRequest $request)
-    {
-        /**
-         * @var Blog $dataRecord
-         */
-        $dataRecord = $this->dataRecord;
-
-        $this->blogPosts = $dataRecord->getBlogPosts();
-
-        return $this->render();
-    }
-
     /**
      * Renders a Blog Member's profile.
      *
      * @throws HTTPResponse_Exception
-     *
+     * @return $this
-     * @return string
      */
     public function profile()
     {
@@ -88,45 +75,59 @@ class BlogController extends PageController
             $this->httpError(404, 'Not Found');
         }
 
-        $profile = $this->getCurrentProfile();
+        // Get profile posts
-
+        $posts = $this->getCurrentProfilePosts();
-        if (!$profile) {
+        if (!$posts) {
-            return $this->httpError(404, 'Not Found');
+            $this->httpError(404, 'Not Found');
         }
 
-        $this->blogPosts = $this->getCurrentProfilePosts();
+        $this->setFilteredPosts($posts);
-
+        return $this;
-        return $this->render();
     }
 
     /**
      * Get the Member associated with the current URL segment.
      *
-     * @return null|Member
+     * @return null|Member|BlogMemberExtension
      */
     public function getCurrentProfile()
     {
-        $urlSegment = $this->request->param('URLSegment');
+        $segment = $this->getCurrentProfileURLSegment();
-        if ($urlSegment) {
+        if (!$segment) {
-            $filter = URLSegmentFilter::create();
+            return null;
-            // url encode unless it's multibyte (already pre-encoded in the database)
-            // see https://github.com/silverstripe/silverstripe-cms/pull/2384
-            if (!$filter->getAllowMultibyte()) {
-                $urlSegment = rawurlencode($urlSegment);
-            }
-
-            return Member::get()
-                ->filter('URLSegment', $urlSegment)
-                ->first();
         }
 
-        return null;
+        /** @var Member $profile */
+        $profile = Member::get()
+            ->find('URLSegment', $segment);
+        return $profile;
+    }
+
+    /**
+     * Get URL Segment of current profile
+     *
+     * @return null|string
+     */
+    public function getCurrentProfileURLSegment()
+    {
+        $segment = isset($this->urlParams['Profile'])
+            ? $this->urlParams['Profile']
+            : null;
+        if (!$segment) {
+            return null;
+        }
+
+        // url encode unless it's multibyte (already pre-encoded in the database)
+        // see https://github.com/silverstripe/silverstripe-cms/pull/2384
+        return URLSegmentFilter::singleton()->getAllowMultibyte()
+            ? $segment
+            : rawurlencode($segment);
     }
 
     /**
      * Get posts related to the current Member profile.
      *
-     * @return null|DataList
+     * @return null|DataList|BlogPost[]
      */
     public function getCurrentProfilePosts()
     {
@@ -142,166 +143,190 @@ class BlogController extends PageController
     /**
      * Renders an archive for a specified date. This can be by year or year/month.
      *
-     * @return null|string
+     * @return $this
+     * @throws HTTPResponse_Exception
      */
     public function archive()
     {
-        /**
-         * @var Blog $dataRecord
-         */
-        $dataRecord = $this->dataRecord;
-
         $year = $this->getArchiveYear();
         $month = $this->getArchiveMonth();
         $day = $this->getArchiveDay();
 
-        if ($this->request->param('Month') && !$month) {
+        // Validate all values
+        if ($year === false || $month === false || $day === false) {
             $this->httpError(404, 'Not Found');
         }
 
-        if ($month && $this->request->param('Day') && !$day) {
+        $posts = $this->data()->getArchivedBlogPosts($year, $month, $day);
-            $this->httpError(404, 'Not Found');
+        $this->setFilteredPosts($posts);
-        }
+        return $this;
-
-        if ($year) {
-            $this->blogPosts = $dataRecord->getArchivedBlogPosts($year, $month, $day);
-
-            return $this->render();
-        }
-
-        $this->httpError(404, 'Not Found');
-
-        return null;
     }
 
     /**
      * Fetches the archive year from the url.
      *
-     * @return int
+     * Returns int if valid, current year if not provided, false if invalid value
+     *
+     * @return int|false
      */
     public function getArchiveYear()
     {
-        if ($this->request->param('Year')) {
+        if (isset($this->urlParams['Year'])
-            if (preg_match('/^[0-9]{4}$/', $year = $this->request->param('Year'))) {
+            && preg_match('/^[0-9]{4}$/', $this->urlParams['Year'])
-                return (int) $year;
+        ) {
-            }
+            return (int)$this->urlParams['Year'];
-        } elseif ($this->request->param('Action') == 'archive') {
+        }
+
+        if ($this->urlParams['Action'] === 'archive') {
             return DBDatetime::now()->Year();
         }
 
-        return null;
+        return false;
     }
 
     /**
      * Fetches the archive money from the url.
      *
-     * @return null|int
+     * Returns int if valid, null if not provided, false if invalid value
+     *
+     * @return null|int|false
      */
     public function getArchiveMonth()
     {
-        $month = $this->request->param('Month');
+        $month = isset($this->urlParams['Month'])
+            ? $this->urlParams['Month']
+            : null;
 
-        if (preg_match('/^[0-9]{1,2}$/', $month)) {
+        if (preg_match('/^[0-9]{1,2}$/', $month)
-            if ($month > 0 && $month < 13) {
+            && $month > 0
-                if (checkdate($month, 01, $this->getArchiveYear())) {
+            && $month < 13
-                    return (int) $month;
+        ) {
-                }
+            return (int)$month;
-            }
         }
 
-        return null;
+        return false;
     }
 
     /**
      * Fetches the archive day from the url.
      *
-     * @return null|int
+     * Returns int if valid, null if not provided, false if invalid value
+     *
+     * @return null|int|false
      */
     public function getArchiveDay()
     {
-        $day = $this->request->param('Day');
+        $day = isset($this->urlParams['Day'])
+            ? $this->urlParams['Day']
+            : null;
 
-        if (preg_match('/^[0-9]{1,2}$/', $day)) {
+        // Cannot calculate day without month and year
-            if (checkdate($this->getArchiveMonth(), $day, $this->getArchiveYear())) {
+        $month = $this->getArchiveMonth();
-                return (int) $day;
+        $year = $this->getArchiveYear();
-            }
+        if (!$month || !$year) {
+            return false;
         }
 
-        return null;
+        if (preg_match('/^[0-9]{1,2}$/', $day) && checkdate($month, $day, $year)) {
+            return (int)$day;
+        }
+
+        return false;
     }
 
     /**
      * Renders the blog posts for a given tag.
      *
-     * @return null|string
+     * @return DBHTMLText|$this
+     * @throws HTTPResponse_Exception
      */
     public function tag()
     {
+        // Ensure tag exists
         $tag = $this->getCurrentTag();
-
+        if (!$tag) {
-        if ($tag) {
+            $this->httpError(404, 'Not Found');
-            $this->blogPosts = $tag->BlogPosts();
-
-            if ($this->isRSS()) {
-                return $this->rssFeed($this->blogPosts, $tag->getLink());
-            } else {
-                return $this->render();
-            }
         }
 
-        $this->httpError(404, 'Not Found');
+        // Get posts with this tag
+        $posts = $this
+            ->data()
+            ->getBlogPosts()
+            ->filter(['Tags.URLSegment' => $tag->URLSegment]); // Soft duplicate handling
 
-        return null;
+        $this->setFilteredPosts($posts);
+
+        // Render as RSS if provided
+        if ($this->isRSS()) {
+            return $this->rssFeed($posts, $tag->getLink());
+        }
+
+        return $this;
     }
 
     /**
-     * Tag Getter for use in templates.
+     * Get BlogTag assigned to current filter
      *
      * @return null|BlogTag
      */
     public function getCurrentTag()
     {
-        /**
+        $segment = $this->getCurrentTagURLSegment();
-         * @var Blog $dataRecord
+        if (!$segment) {
-         */
+            return null;
-        $dataRecord = $this->dataRecord;
-        $tag = $this->request->param('Tag');
-        if ($tag) {
-            $filter = URLSegmentFilter::create();
-            // url encode unless it's multibyte (already pre-encoded in the database)
-            // see https://github.com/silverstripe/silverstripe-cms/pull/2384
-            if (!$filter->getAllowMultibyte()) {
-                $tag = rawurlencode($tag);
-            }
-
-            return $dataRecord->Tags()
-                ->filter('URLSegment', $tag)
-                ->first();
         }
-        return null;
+
+        /** @var BlogTag $tag */
+        $tag = $this
+            ->data()
+            ->Tags(false)// Show "no results" instead of "404"
+            ->find('URLSegment', $segment);
+        return $tag;
+    }
+
+    /**
+     * Get URLSegment of selected category (not: URLEncoded based on multibyte)
+     *
+     * @return string|null
+     */
+    public function getCurrentTagURLSegment()
+    {
+        $segment = isset($this->urlParams['Tag'])
+            ? $this->urlParams['Tag']
+            : null;
+
+        // url encode unless it's multibyte (already pre-encoded in the database)
+        // see https://github.com/silverstripe/silverstripe-cms/pull/2384
+        return URLSegmentFilter::singleton()->getAllowMultibyte()
+            ? $segment
+            : rawurlencode($segment);
     }
 
     /**
      * Renders the blog posts for a given category.
      *
-     * @return null|string
+     * @return DBHTMLText|$this
+     * @throws HTTPResponse_Exception
      */
     public function category()
     {
         $category = $this->getCurrentCategory();
 
-        if ($category) {
+        if (!$category) {
-            $this->blogPosts = $category->BlogPosts();
+            $this->httpError(404, 'Not Found');
-
-            if ($this->isRSS()) {
-                return $this->rssFeed($this->blogPosts, $category->getLink());
-            }
-            return $this->render();
         }
 
-        $this->httpError(404, 'Not Found');
+        // Get posts with this category
+        $posts = $this
+            ->data()
+            ->getBlogPosts()
+            ->filter(['Categories.URLSegment' => $category->URLSegment]); // Soft duplicate handling
+        $this->setFilteredPosts($posts);
 
-        return null;
+        if ($this->isRSS()) {
+            return $this->rssFeed($posts, $category->getLink());
+        }
+        return $this;
     }
 
     /**
@@ -311,24 +336,35 @@ class BlogController extends PageController
      */
     public function getCurrentCategory()
     {
-        /**
+        $segment = $this->getCurrentCategoryURLSegment();
-         * @var Blog $dataRecord
+        if (!$segment) {
-         */
+            return null;
-        $dataRecord = $this->dataRecord;
-        $category = $this->request->param('Category');
-        if ($category) {
-            $filter = URLSegmentFilter::create();
-            // url encode unless it's multibyte (already pre-encoded in the database)
-            // see https://github.com/silverstripe/silverstripe-cms/pull/2384
-            if (!$filter->getAllowMultibyte()) {
-                $category = rawurlencode($category);
-            }
-
-            return $dataRecord->Categories()
-                ->filter('URLSegment', $category)
-                ->first();
         }
-        return null;
+
+        /** @var BlogCategory $category */
+        $category = $this
+            ->data()
+            ->Categories(false)// Show "no results" instead of "404"
+            ->find('URLSegment', $segment);
+        return $category;
+    }
+
+    /**
+     * Get URLSegment of selected category
+     *
+     * @return string|null
+     */
+    public function getCurrentCategoryURLSegment()
+    {
+        $segment = isset($this->urlParams['Category'])
+            ? $this->urlParams['Category']
+            : null;
+
+        // url encode unless it's multibyte (already pre-encoded in the database)
+        // see https://github.com/silverstripe/silverstripe-cms/pull/2384
+        return URLSegmentFilter::singleton()->getAllowMultibyte()
+            ? $segment
+            : rawurlencode($segment);
     }
 
     /**
@@ -406,13 +442,13 @@ class BlogController extends PageController
             );
         }
 
-        if ($this->owner->getArchiveYear()) {
+        if ($this->getArchiveYear()) {
-            if ($this->owner->getArchiveDay()) {
+            if ($this->getArchiveDay()) {
-                $date = $this->owner->getArchiveDate()->Nice();
+                $date = $this->getArchiveDate()->Nice();
-            } elseif ($this->owner->getArchiveMonth()) {
+            } elseif ($this->getArchiveMonth()) {
-                $date = $this->owner->getArchiveDate()->format('MMMM, y');
+                $date = $this->getArchiveDate()->format('MMMM, y');
             } else {
-                $date = $this->owner->getArchiveDate()->format('y');
+                $date = $this->getArchiveDate()->format('y');
             }
 
             $items[] = _t(
@@ -436,6 +472,28 @@ class BlogController extends PageController
         return $result;
     }
 
+    /**
+     * Get filtered blog posts
+     *
+     * @return DataList|BlogPost[]
+     */
+    public function getFilteredPosts()
+    {
+        return $this->blogPosts ?: $this->data()->getBlogPosts();
+    }
+
+    /**
+     * Set filtered posts
+     *
+     * @param SS_List|BlogPost[] $posts
+     * @return $this
+     */
+    public function setFilteredPosts($posts)
+    {
+        $this->blogPosts = $posts;
+        return $this;
+    }
+
     /**
      * Returns a list of paginated blog posts based on the BlogPost dataList.
      *
@@ -443,12 +501,12 @@ class BlogController extends PageController
      */
     public function PaginatedList()
     {
-        $allPosts = $this->blogPosts ?: ArrayList::create();
+        $allPosts = $this->getFilteredPosts();
         $posts = PaginatedList::create($allPosts);
 
         // Set appropriate page size
-        if ($this->PostsPerPage > 0) {
+        if ($this->data()->PostsPerPage > 0) {
-            $pageSize = $this->PostsPerPage;
+            $pageSize = $this->data()->PostsPerPage;
         } elseif ($count = $allPosts->count()) {
             $pageSize = $count;
         } else {
@@ -482,7 +540,7 @@ class BlogController extends PageController
         return null;
     }
 
-     /**
+    /**
      * Returns the absolute link to the previous page for use in the page meta tags. This helps search engines
      * find the pagination and index all pages properly.
      *
@@ -507,14 +565,7 @@ class BlogController extends PageController
      */
     public function rss()
     {
-        /**
+        return $this->rssFeed($this->getFilteredPosts(), $this->Link());
-         * @var Blog $dataRecord
-         */
-        $dataRecord = $this->dataRecord;
-
-        $this->blogPosts = $dataRecord->getBlogPosts();
-
-        return $this->rssFeed($this->blogPosts, $this->Link());
     }
 
     /**
@@ -561,13 +612,18 @@ class BlogController extends PageController
      * Displays an RSS feed of the given blog posts.
      *
      * @param DataList $blogPosts
-     * @param string $link
+     * @param string   $link
      *
-     * @return string
+     * @return DBHTMLText
      */
     protected function rssFeed($blogPosts, $link)
     {
-        $rss = RSSFeed::create($blogPosts, $link, $this->MetaTitle, $this->MetaDescription);
+        $rss = RSSFeed::create(
+            $blogPosts,
+            $link,
+            $this->getMetaTitle(),
+            $this->data()->MetaDescription
+        );
 
         $this->extend('updateRss', $rss);
 
@@ -581,7 +637,6 @@ class BlogController extends PageController
      */
     protected function isRSS()
     {
-        $rss = $this->request->param('Rss');
+        return isset($this->urlParams['RSS']) && strcasecmp($this->urlParams['RSS'], 'rss') == 0;
-        return (is_string($rss) && strcasecmp($rss, 'rss') == 0);
     }
 }

src/Model/BlogMemberExtension.php

@@ -10,6 +10,7 @@ use SilverStripe\Forms\GridField\GridFieldAddNewButton;
 use SilverStripe\Forms\Tab;
 use SilverStripe\Forms\TextareaField;
 use SilverStripe\ORM\DataExtension;
+use SilverStripe\ORM\ManyManyList;
 use SilverStripe\Security\Member;
 use SilverStripe\View\Parsers\URLSegmentFilter;
 use SilverStripe\View\Requirements;
@@ -17,6 +18,10 @@ use SilverStripe\View\Requirements;
 /**
  * This class is responsible for add Blog specific behaviour to Members.
  *
+ * @property string $URLSegment
+ * @property string $BlogProfileSummary
+ * @method Image BlogProfileImage()
+ * @method ManyManyList|BlogPost[] BlogPosts()
  */
 class BlogMemberExtension extends DataExtension
 {

src/Model/BlogObject.php

@@ -8,6 +8,7 @@ use SilverStripe\Forms\Tab;
 use SilverStripe\Forms\TabSet;
 use SilverStripe\Forms\TextField;
 use SilverStripe\ORM\DataList;
+use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\ValidationResult;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
@@ -20,7 +21,7 @@ use SilverStripe\View\Parsers\URLSegmentFilter;
 trait BlogObject
 {
     /**
-     * @return DataList
+     * @return ManyManyList|BlogPost[]
      */
     public function BlogPosts()
     {
@@ -31,6 +32,22 @@ trait BlogObject
         return $blogPosts;
     }
 
+    /**
+     * Get blog this tag was queried from
+     *
+     * @return Blog|null
+     */
+    public function Blog()
+    {
+        $blogID = $this->getSourceQueryParam('BlogID');
+        if ($blogID) {
+            /** @var Blog $blog */
+            $blog = Blog::get()->byID($blogID);
+            return $blog;
+        }
+        return null;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -75,14 +92,18 @@ trait BlogObject
     }
 
     /**
-     * Returns a relative link to this category.
+     * Returns a relative link to this category or tag
      *
      * @return string
      */
     public function getLink()
     {
+        $blog = $this->Blog();
+        if (!$blog) {
+            return null;
+        }
         return Controller::join_links(
-            $this->Blog()->Link(),
+            $blog->Link(),
             $this->getListUrlSegment(),
             $this->URLSegment
         );
@@ -158,14 +179,12 @@ trait BlogObject
         return $this->Blog()->canEdit($member);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function onBeforeWrite()
     {
         parent::onBeforeWrite();
+
         if ($this->exists() || empty($this->URLSegment)) {
-            return $this->generateURLSegment();
+            $this->generateURLSegment();
         }
     }
 
@@ -178,7 +197,7 @@ trait BlogObject
      */
     public function generateURLSegment($increment = 0)
     {
-        $increment = (int) $increment;
+        $increment = (int)$increment;
         $filter = URLSegmentFilter::create();
 
         // Setting this to on. Because of the UI flow, it would be quite a lot of work
@@ -209,12 +228,7 @@ trait BlogObject
     protected function getDuplicatesByField($field)
     {
         $duplicates = DataList::create(self::class)
-            ->filter(
+            ->filter([$field => $this->$field]);
-                [
-                    $field   => $this->$field,
-                    'BlogID' => (int) $this->BlogID
-                ]
-            );
 
         if ($this->ID) {
             $duplicates = $duplicates->exclude('ID', $this->ID);

src/Model/BlogPost.php

@@ -313,14 +313,6 @@ class BlogPost extends Page
             }
 
             // Get categories and tags
-            $parent = $this->Parent();
-            $categories = $parent instanceof Blog
-                ? $parent->Categories()
-                : BlogCategory::get();
-            $tags = $parent instanceof Blog
-                ? $parent->Tags()
-                : BlogTag::get();
-
             // @todo: Reimplement the sidebar
             // $options = BlogAdminSidebar::create(
             $fields->addFieldsToTab(
@@ -330,7 +322,7 @@ class BlogPost extends Page
                     TagField::create(
                         'Categories',
                         _t(__CLASS__ . '.Categories', 'Categories'),
-                        $categories,
+                        BlogCategory::get(),
                         $this->Categories()
                     )
                         ->setCanCreate($this->canCreateCategories())
@@ -338,7 +330,7 @@ class BlogPost extends Page
                     TagField::create(
                         'Tags',
                         _t(__CLASS__ . '.Tags', 'Tags'),
-                        $tags,
+                        BlogTag::get(),
                         $this->Tags()
                     )
                         ->setCanCreate($this->canCreateTags())
@@ -816,4 +808,16 @@ class BlogPost extends Page
             $this->Authors()->add($member);
         }
     }
+
+    /**
+     * So that tags / categories queried through this post generate the correct Link()
+     *
+     * @return array
+     */
+    public function getInheritableQueryParams()
+    {
+        $params = parent::getInheritableQueryParams();
+        $params['BlogID'] = $this->ParentID;
+        return $params;
+    }
 }

src/Model/BlogTag.php

@@ -3,6 +3,7 @@
 namespace SilverStripe\Blog\Model;
 
 use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\ManyManyList;
 
 /**
  * A blog tag for keyword descriptions of a blog post.
@@ -10,9 +11,9 @@ use SilverStripe\ORM\DataObject;
  *
  * @method Blog Blog()
  *
+ * @method ManyManyList|BlogPost[] BlogPosts()
  * @property string $Title
  * @property string $URLSegment
- * @property int $BlogID
  */
 class BlogTag extends DataObject implements CategorisationObject
 {
@@ -44,8 +45,8 @@ class BlogTag extends DataObject implements CategorisationObject
     /**
      * @var array
      */
-    private static $has_one = [
+    private static $indexes = [
-        'Blog' => Blog::class
+        'URLSegment' => true,
     ];
 
     /**

src/Model/CategorisationObject.php

@@ -2,8 +2,10 @@
 
 namespace SilverStripe\Blog\Model;
 
+use SilverStripe\ORM\ManyManyList;
+
 /**
- * @method ManyManyList BlogPosts
+ * @method ManyManyList|BlogPost[] BlogPosts()
  */
 interface CategorisationObject
 {