[FEATURE] Add a filter plugin that combines category and tag

More filters are possible via filter interface.

Classes/Constants.php

@@ -66,5 +66,6 @@ class Constants
         'blog_commentswidget'       => -1600000017,
         'blog_archivewidget'        => -1600000018,
         'blog_feedwidget'           => -1600000019,
+        'blog_filter'               => -1600000020,
     ];
 }

Classes/Controller/PostController.php

@@ -12,6 +12,7 @@
 
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
+use T3G\AgencyPack\Blog\Domain\Factory\PostFilterFactory;
 use T3G\AgencyPack\Blog\Domain\Model\Author;
 use T3G\AgencyPack\Blog\Domain\Model\Category;
 use T3G\AgencyPack\Blog\Domain\Model\Post;
@@ -27,6 +28,7 @@
 use T3G\AgencyPack\Blog\Utility\ArchiveUtility;
 use TYPO3\CMS\Core\Http\NormalizedParams;
 use TYPO3\CMS\Core\Site\Entity\SiteLanguage;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
 use TYPO3\CMS\Extbase\Pagination\QueryResultPaginator;
 use TYPO3\CMS\Extbase\Persistence\QueryResultInterface;
@@ -251,6 +253,29 @@ public function listPostsByTagAction(?Tag $tag = null, int $currentPage = 1): Re
         return $this->htmlResponse();
     }
 
+    /**
+     * Show a list of posts by given filter.
+     */
+    public function listPostsByFilterAction(int $currentPage = 1): ResponseInterface
+    {
+        $factory = GeneralUtility::makeInstance(PostFilterFactory::class, $this->categoryRepository, $this->tagRepository);
+        $filter = $factory->getFilterFromRequest($this->request);
+        $posts = $this->postRepository->findAllByFilter($filter);
+        $pagination = $this->getPagination($posts, $currentPage);
+
+        $this->view->assign('type', 'byfilter');
+        $this->view->assign('posts', $posts);
+        $this->view->assign('pagination', $pagination);
+        $this->view->assign('filter', $filter);
+        $this->view->assign('categories', $this->categoryRepository->findAll());
+        $this->view->assign('tags', $this->tagRepository->findAll());
+
+        MetaTagService::set(MetaTagService::META_TITLE, $filter->getTitle());
+        MetaTagService::set(MetaTagService::META_DESCRIPTION, $filter->getDescription());
+
+        return $this->htmlResponse();
+    }
+
     /**
      * Sidebar action.
      */

Classes/Domain/Factory/PostFilterFactory.php

@@ -0,0 +1,47 @@
+<?php
+declare(strict_types = 1);
+
+/*
+ * This file is part of the package t3g/blog.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace T3G\AgencyPack\Blog\Domain\Factory;
+
+use T3G\AgencyPack\Blog\Domain\Filter\Post\CategoryTag;
+use T3G\AgencyPack\Blog\Domain\Filter\PostFilter;
+use T3G\AgencyPack\Blog\Domain\Repository\CategoryRepository;
+use T3G\AgencyPack\Blog\Domain\Repository\TagRepository;
+use TYPO3\CMS\Core\SingletonInterface;
+use TYPO3\CMS\Extbase\Mvc\RequestInterface;
+
+/**
+ * The post filter factory sets filter values from the request.
+ */
+class PostFilterFactory implements SingletonInterface
+{
+    protected CategoryRepository $categoryRepository;
+
+    protected TagRepository $tagRepository;
+
+    public function __construct(CategoryRepository $categoryRepository, TagRepository $tagRepository)
+    {
+        $this->categoryRepository = $categoryRepository;
+        $this->tagRepository = $tagRepository;
+    }
+
+    public function getFilterFromRequest(RequestInterface $request): PostFilter
+    {
+        // Currently there is only one filter implementation.
+        $filter = new CategoryTag();
+        if ($request->hasArgument('category')) {
+            $filter->setCategory($this->categoryRepository->findByUid((int)$request->getArgument('category')));
+        }
+        if ($request->hasArgument('tag')) {
+            $filter->setTag($this->tagRepository->findByUid((int)$request->getArgument('tag')));
+        }
+        return $filter;
+    }
+}

Classes/Domain/Filter/Post/AbstractBase.php

@@ -0,0 +1,29 @@
+<?php
+declare(strict_types = 1);
+
+/*
+ * This file is part of the package t3g/blog.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace T3G\AgencyPack\Blog\Domain\Filter\Post;
+
+use T3G\AgencyPack\Blog\Domain\Filter\PostFilter;
+
+/**
+ * Base class for all post filters.
+ */
+abstract class AbstractBase implements PostFilter
+{
+    /**
+     * The class name (without namespace) is used as the filter's name.
+     */
+    public function getName(): string
+    {
+        $classWithNamespace = get_class($this);
+        $rightBackslash = strrpos($classWithNamespace, '\\') ?? 0;
+        return substr($classWithNamespace, $rightBackslash > 0 ? ++$rightBackslash : $rightBackslash);
+    }
+}

Classes/Domain/Filter/Post/CategoryTag.php

@@ -0,0 +1,99 @@
+<?php
+declare(strict_types = 1);
+
+/*
+ * This file is part of the package t3g/blog.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace T3G\AgencyPack\Blog\Domain\Filter\Post;
+
+use T3G\AgencyPack\Blog\Domain\Model\Category;
+use T3G\AgencyPack\Blog\Domain\Model\Tag;
+use TYPO3\CMS\Extbase\Persistence\Exception\InvalidQueryException;
+use TYPO3\CMS\Extbase\Persistence\Generic\Qom\ComparisonInterface;
+use TYPO3\CMS\Extbase\Persistence\QueryInterface;
+
+/**
+ * This filter combines one selected Category and one selected Tag (both optional).
+ */
+class CategoryTag extends AbstractBase
+{
+    protected ?Category $category = null;
+
+    protected ?Tag $tag = null;
+
+    /**
+     * Title is simply the concatenated Category and Tag titles (separated by a SPACE character).
+     */
+    public function getTitle(): string
+    {
+        if ($this->category) {
+            if ($this->tag) {
+                return trim($this->category->getTitle() . ' ' . $this->tag->getTitle());
+            } else {
+                return $this->category->getTitle();
+            }
+        }
+        if ($this->tag) {
+            return $this->tag->getTitle();
+        }
+        return '';
+    }
+
+    /**
+     * Description is simply the concatenated Category and Tag titles (separated by a SPACE character).
+     */
+    public function getDescription(): string
+    {
+        if ($this->category) {
+            if ($this->tag) {
+                return trim($this->category->getDescription() . ' ' . $this->tag->getDescription());
+            } else {
+                return $this->category->getDescription();
+            }
+        }
+        if ($this->tag) {
+            return $this->tag->getDescription();
+        }
+        return '';
+    }
+
+    /**
+     * @return array<ComparisonInterface>
+     * @throws InvalidQueryException
+     */
+    public function getConstraints(QueryInterface $query): array
+    {
+        $constraints = [];
+        if ($this->category) {
+            $constraints[] = $query->contains('categories', $this->category);
+        }
+        if ($this->tag) {
+            $constraints[] = $query->contains('tags', $this->tag);
+        }
+        return $constraints;
+    }
+
+    public function getCategory(): ?Category
+    {
+        return $this->category;
+    }
+
+    public function setCategory(?Category $category): void
+    {
+        $this->category = $category;
+    }
+
+    public function getTag(): ?Tag
+    {
+        return $this->tag;
+    }
+
+    public function setTag(?Tag $tag): void
+    {
+        $this->tag = $tag;
+    }
+}

Classes/Domain/Filter/PostFilter.php

@@ -0,0 +1,42 @@
+<?php
+declare(strict_types = 1);
+
+/*
+ * This file is part of the package t3g/blog.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace T3G\AgencyPack\Blog\Domain\Filter;
+
+use TYPO3\CMS\Extbase\Persistence\Generic\Qom\ComparisonInterface;
+use TYPO3\CMS\Extbase\Persistence\QueryInterface;
+
+/**
+ * Interface for post filters used in the listPostsByFilterAction.
+ */
+interface PostFilter
+{
+    /**
+     * The name of this filter, used for rendering the corresponding Fluid partial.
+     */
+    public function getName(): string;
+
+    /**
+     * The title of the filter result, used in MetaTagService.
+     */
+    public function getTitle(): string;
+
+    /**
+     * A description of the filter result, used in MetaTagService.
+     */
+    public function getDescription(): string;
+
+    /**
+     * Apply current filter values in given Posts query.
+     *
+     * @return array<ComparisonInterface>
+     */
+    public function getConstraints(QueryInterface $query): array;
+}

Classes/Domain/Repository/PostRepository.php

@@ -13,6 +13,7 @@
 use Psr\Http\Message\ServerRequestInterface;
 use T3G\AgencyPack\Blog\Constants;
 use T3G\AgencyPack\Blog\DataTransferObject\PostRepositoryDemand;
+use T3G\AgencyPack\Blog\Domain\Filter\PostFilter;
 use T3G\AgencyPack\Blog\Domain\Model\Author;
 use T3G\AgencyPack\Blog\Domain\Model\Category;
 use T3G\AgencyPack\Blog\Domain\Model\Post;
@@ -226,6 +227,18 @@ public function findAllByTag(Tag $tag): QueryResultInterface
         return $query->matching($query->logicalAnd(...$constraints))->execute();
     }
 
+    public function findAllByFilter(PostFilter $filter): QueryResultInterface
+    {
+        $query = $this->createQuery();
+        $constraints = array_merge($this->defaultConstraints, $filter->getConstraints($query));
+        $storagePidConstraint = $this->getStoragePidConstraint();
+        if ($storagePidConstraint instanceof ComparisonInterface) {
+            $constraints[] = $storagePidConstraint;
+        }
+
+        return $query->matching($query->logicalAnd(...$constraints))->execute();
+    }
+
     public function findByMonthAndYear(int $year, int $month = null): QueryResultInterface
     {
         $query = $this->createQuery();

Configuration/TCA/Overrides/tt_content.php

@@ -57,6 +57,14 @@
 );
 $GLOBALS['TCA']['tt_content']['types']['list']['subtypes_excludelist']['blog_archive'] = 'select_key';
 
+\TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerPlugin(
+    'Blog',
+    'Filter',
+    'LLL:EXT:blog/Resources/Private/Language/locallang_db.xlf:plugin.blog_filter.title',
+    'plugin-blog-filter'
+);
+$GLOBALS['TCA']['tt_content']['types']['list']['subtypes_excludelist']['blog_filter'] = 'select_key';
+
 \TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerPlugin(
     'Blog',
     'Sidebar',

Configuration/TsConfig/Page/Wizards.tsconfig

@@ -59,6 +59,15 @@ mod.wizards.newContentElement.wizardItems.blog {
                 list_type = blog_archive
             }
         }
+        blog_filter {
+            iconIdentifier = plugin-blog-filter
+            title = LLL:EXT:blog/Resources/Private/Language/locallang_db.xlf:plugin.blog_filter.title
+            description = LLL:EXT:blog/Resources/Private/Language/locallang_db.xlf:plugin.blog_filter.description
+            tt_content_defValues {
+                CType = list
+                list_type = blog_filter
+            }
+        }
         blog_demandedposts {
             iconIdentifier = plugin-blog-demandedposts
             title = LLL:EXT:blog/Resources/Private/Language/locallang_db.xlf:plugin.blog_demandedposts.title

Configuration/TypoScript/Static/setup.typoscript

@@ -440,3 +440,8 @@ blog_rss_author < blog_rss_posts
 blog_rss_author.typeNum = 250
 blog_rss_author.10 < tt_content.list.20.blog_authorposts
 blog_rss_author.10.format = rss
+
+blog_rss_filter < blog_rss_posts
+blog_rss_filter.typeNum = 260
+blog_rss_filter.10 < tt_content.list.20.blog_filter
+blog_rss_filter.10.format = rss

Resources/Private/Language/locallang.xlf

@@ -58,6 +58,9 @@
             <trans-unit id="headline.rssfeed" xml:space="preserve">
                 <source>RSS-Feeds</source>
             </trans-unit>
+            <trans-unit id="headline.filter" xml:space="preserve">
+                <source>Filter</source>
+            </trans-unit>
 
             <!-- Form -->
             <trans-unit id="form.comment.name" xml:space="preserve">
@@ -210,6 +213,14 @@
                 <source>Show Archive</source>
             </trans-unit>
 
+            <!-- Filter -->
+            <trans-unit id="filter.category.all" xml:space="preserve">
+                <source>All categories</source>
+            </trans-unit>
+            <trans-unit id="filter.tag.all" xml:space="preserve">
+                <source>All tags</source>
+            </trans-unit>
+
             <!-- Backend -->
             <trans-unit id="backend.headline.setup_wizard" xml:space="preserve">
                 <source>SetupWizard</source>

Resources/Private/Language/locallang_db.xlf

@@ -47,6 +47,12 @@
             <trans-unit id="plugin.blog_tag.description" xml:space="preserve">
                 <source>Allows the users to show all posts tagged with a specific keyword.</source>
             </trans-unit>
+            <trans-unit id="plugin.blog_filter.title" xml:space="preserve">
+                <source>Blog: List by filter</source>
+            </trans-unit>
+            <trans-unit id="plugin.blog_filter.description" xml:space="preserve">
+                <source>Allows the users to show a list of filtered posts.</source>
+            </trans-unit>
             <trans-unit id="plugin.blog_archive.title" xml:space="preserve">
                 <source>Blog: Archive</source>
             </trans-unit>