Allow passing custom param value converters

README.md

@@ -243,6 +243,31 @@ $output = $client->selectWithParams(
 All types are supported (except `AggregateFunction`, `SimpleAggregateFunction` and `Nothing` by design).
 You can also pass `DateTimeInterface` into `Date*` types or native array into `Array`, `Tuple`, `Native` and `Geo` types
 
+### Custom Query Parameter Value Conversion
+
+Query parameters passed to `selectWithParams()` are converted into an HTTP-API-compatible format. To overwrite an existing value converter or
+provide a converter for a type that the library does not (yet) support, pass these to the
+`SimPod\ClickHouseClient\Param\ParamValueConverterRegistry` constructor:
+
+```php
+<?php
+
+use SimPod\ClickHouseClient\Client\Http\RequestFactory;
+use SimPod\ClickHouseClient\Client\PsrClickHouseClient;
+use SimPod\ClickHouseClient\Exception\UnsupportedParamValue;
+use SimPod\ClickHouseClient\Param\ParamValueConverterRegistry;
+
+$paramValueConverterRegistry = new ParamValueConverterRegistry([
+    'datetime' => static fn (mixed $v) => $v instanceof DateTimeInterface ? $v->format('c') : throw UnsupportedParamValue::type($value)
+]);
+
+$client = new PsrClickHouseClient(..., new RequestFactory($paramValueConverterRegistry, ...));
+```
+
+Be aware that the library can not ensure that passed values have a certain type. They are passed as-is and closures must accept `mixed` values.
+
+Throw an exception of type `UnsupportedParamValue` if your converter does not support the passed value type.
+
 ### Expression
 
 To represent complex expressions there's `SimPod\ClickHouseClient\Sql\Expression` class. When passed to `SqlFactory` its value gets evaluated.

src/Param/ParamValueConverterRegistry.php

@@ -12,6 +12,7 @@
 
 use function array_keys;
 use function array_map;
+use function array_merge;
 use function explode;
 use function implode;
 use function in_array;
@@ -24,7 +25,10 @@
 use function strtolower;
 use function trim;
 
-/** @phpstan-type Converter = Closure(mixed, Type|string|null, bool):(StreamInterface|string) */
+/**
+ * @phpstan-type Converter = Closure(mixed, Type|string|null, bool):(StreamInterface|string)
+ * @phpstan-type ConverterRegistry = array<string, Converter>
+ */
 final class ParamValueConverterRegistry
 {
     /** @var list<string> */
@@ -44,10 +48,11 @@ final class ParamValueConverterRegistry
         'json',
     ];
 
-    /** @phpstan-var array<string, Converter> */
+    /** @phpstan-var ConverterRegistry */
     private array $registry;
 
-    public function __construct()
+    /** @phpstan-param ConverterRegistry $registry */
+    public function __construct(array $registry = [])
     {
         $formatPoint = static fn (array $point) => sprintf('(%s)', implode(',', $point));
         // phpcs:ignore SlevomatCodingStandard.Functions.RequireArrowFunction.RequiredArrowFunction
@@ -67,8 +72,8 @@ public function __construct()
             ));
         };
 
-        /** @phpstan-var array<string, Converter> $registry */
-        $registry       = [
+        /** @phpstan-var ConverterRegistry $defaultRegistry */
+        $defaultRegistry = [
             'String' => self::stringConverter(),
             'FixedString' => self::stringConverter(),
 
@@ -208,7 +213,7 @@ public function __construct()
                 return '(' . $innerExpression . ')';
             },
         ];
-        $this->registry = $registry;
+        $this->registry  = array_merge($defaultRegistry, $registry);
     }
 
     /**

tests/Param/ParamValueConverterRegistryTest.php

@@ -5,13 +5,16 @@
 namespace SimPod\ClickHouseClient\Tests\Param;
 
 use DateTimeImmutable;
+use DateTimeInterface;
+use DateTimeZone;
 use Generator;
 use PHPUnit\Framework\Attributes\BeforeClass;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\DataProvider;
 use Psr\Http\Client\ClientExceptionInterface;
 use SimPod\ClickHouseClient\Exception\ServerError;
 use SimPod\ClickHouseClient\Exception\UnsupportedParamType;
+use SimPod\ClickHouseClient\Exception\UnsupportedParamValue;
 use SimPod\ClickHouseClient\Format\JsonEachRow;
 use SimPod\ClickHouseClient\Format\TabSeparated;
 use SimPod\ClickHouseClient\Param\ParamValueConverterRegistry;
@@ -294,4 +297,22 @@ public function testThrowsOnUnknownType(): void
         $this->expectException(UnsupportedParamType::class);
         $registry->get('fOo');
     }
+
+    public function testParameterRegistryOverwrite(): void
+    {
+        $registry = new ParamValueConverterRegistry([
+            'datetime' => static fn (mixed $value) => $value instanceof DateTimeInterface
+                ? $value->format('c')
+                : throw UnsupportedParamValue::value($value),
+        ]);
+
+        self::assertSame(
+            '2025-01-28T16:00:00+01:00',
+            $registry->get('datetime')(
+                new DateTimeImmutable('2025-01-28T16:00:00', new DateTimeZone('+0100')),
+                null,
+                false,
+            ),
+        );
+    }
 }