feat: add tag filtering to blog posts and implement JSON_CONTAINS DQL function

src/Shared/Doctrine/JsonContains.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Shared\Doctrine;
+
+use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
+use Doctrine\ORM\Query\Parser;
+use Doctrine\ORM\Query\SqlWalker;
+use Doctrine\ORM\Query\TokenType;
+
+/**
+ * JSON_CONTAINS(json_doc, candidate) DQL function for MariaDB/MySQL.
+ * Usage: WHERE JSON_CONTAINS(b.tags, :tag) = 1
+ */
+class JsonContains extends FunctionNode
+{
+    private Node $jsonDoc;
+    private Node $candidate;
+
+    public function parse(Parser $parser): void
+    {
+        $parser->match(TokenType::T_IDENTIFIER);
+        $parser->match(TokenType::T_OPEN_PARENTHESIS);
+        $this->jsonDoc = $parser->StringPrimary();
+        $parser->match(TokenType::T_COMMA);
+        $this->candidate = $parser->StringPrimary();
+        $parser->match(TokenType::T_CLOSE_PARENTHESIS);
+    }
+
+    public function getSql(SqlWalker $sqlWalker): string
+    {
+        return sprintf(
+            'JSON_CONTAINS(%s, %s)',
+            $this->jsonDoc->dispatch($sqlWalker),
+            $this->candidate->dispatch($sqlWalker)
+        );
+    }
+}