Update custom mapping example (#2654)

The previous example was a simplified copy of the date type. In order to present something more useful, the new example is inspired by MongoDB's codec tutorial.

Author: GromNaN

docs/en/reference/custom-mapping-types.rst

@@ -7,45 +7,58 @@ to replace the existing implementation of a mapping type.
 
 In order to create a new mapping type you need to subclass
 ``Doctrine\ODM\MongoDB\Types\Type`` and implement/override
-the methods. Here is an example skeleton of such a custom type
-class:
+the methods.
+
+The following example defines a custom type that stores ``DateTimeInterface``
+instances as an embedded document containing a BSON date and accompanying
+timezone string. Those same embedded documents are then be translated back into
+a ``DateTimeImmutable`` when the data is read from the database.
 
 .. code-block:: php
 
     <?php
 
     namespace My\Project\Types;
 
+    use DateTimeImmutable;
+    use DateTimeZone;
     use Doctrine\ODM\MongoDB\Types\ClosureToPHP;
     use Doctrine\ODM\MongoDB\Types\Type;
     use MongoDB\BSON\UTCDateTime;
 
-    /**
-     * My custom datatype.
-     */
-    class MyType extends Type
+    class DateTimeWithTimezoneType extends Type
     {
         // This trait provides default closureToPHP used during data hydration
         use ClosureToPHP;
 
-        public function convertToPHPValue($value): \DateTime
+        public function convertToPHPValue($value): DateTimeImmutable
         {
-            // This is called to convert a Mongo value to a PHP representation
-            return $value->toDateTime();
+            $timeZone = new DateTimeZone($value['tz']);
+            $dateTime = $value['utc']
+                ->toDateTime()
+                ->setTimeZone($timeZone);
+
+            return DateTimeImmutable::createFromMutable($dateTime);
         }
 
-        public function convertToDatabaseValue($value): UTCDateTime
+        public function convertToDatabaseValue($value): array
         {
-            // This is called to convert a PHP value to its Mongo equivalent
-            return new UTCDateTime($value);
+            if (! isset($value['utc'], $value['tz'])) {
+                throw new RuntimeException('Database value cannot be converted to date with timezone. Expected array with "utc" and "tz" keys.');
+            }
+
+            return [
+                'utc' => new UTCDateTime($value),
+                'tz' => $value->getTimezone()->getName(),
+            ];
         }
     }
 
 Restrictions to keep in mind:
 
 -
-   If the value of the field is *NULL* the method
-   ``convertToDatabaseValue()`` is not called.
+   If the value of the field is *NULL* the method ``convertToDatabaseValue()``
+   is not called. You don't need to check for *NULL* values.
 -
    The ``UnitOfWork`` never passes values to the database convert
    method that did not change in the request.
@@ -59,41 +72,38 @@ know about it:
 
     // in bootstrapping code
 
-    // ...
-
     use Doctrine\ODM\MongoDB\Types\Type;
 
-    // ...
-
     // Adds a type. This results in an exception if type with given name is already registered
-    Type::addType('mytype', \My\Project\Types\MyType::class);
+    Type::addType('date_with_timezone', \My\Project\Types\DateTimeWithTimezoneType::class);
 
     // Overrides a type. This results in an exception if type with given name is not registered
-    Type::overrideType('mytype', \My\Project\Types\MyType::class);
+    Type::overrideType('date_immutable', \My\Project\Types\DateTimeWithTimezoneType::class);
 
     // Registers a type without checking whether it was already registered
-    Type::registerType('mytype', \My\Project\Types\MyType::class);
+    Type::registerType('date_immutable', \My\Project\Types\DateTimeWithTimezoneType::class);
 
-As can be seen above, when registering the custom types in the
-configuration you specify a unique name for the mapping type and
-map that to the corresponding |FQCN|. Now you can use your new
-type in your mapping like this:
+As can be seen above, when registering the custom types in the configuration you
+specify a unique name for the mapping type and map that to the corresponding
+|FQCN|. Now you can use your new type in your mapping like this:
 
 .. configuration-block::
 
     .. code-block:: php
 
         <?php
 
-        class MyPersistentClass
+        use DateTimeImmutable;
+
+        class Thing
         {
-            #[Field(type: 'mytype')]
-            private \DateTime $field;
+            #[Field(type: 'date_with_timezone')]
+            public DateTimeImmutable $date;
         }
 
     .. code-block:: xml
 
-        <field field-name="field" type="mytype" />
+        <field field-name="field" type="date_with_timezone" />
 
 .. |FQCN| raw:: html
   <abbr title="Fully-Qualified Class Name">FQCN</abbr>

tests/Documentation/CustomMapping/CustomMappingTest.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Documentation\CustomMapping;
+
+use DateTimeImmutable;
+use DateTimeZone;
+use Doctrine\ODM\MongoDB\Tests\BaseTestCase;
+use Doctrine\ODM\MongoDB\Types\Type;
+
+class CustomMappingTest extends BaseTestCase
+{
+    public function testTest(): void
+    {
+        Type::addType('date_with_timezone', DateTimeWithTimezoneType::class);
+        Type::overrideType('date_immutable', DateTimeWithTimezoneType::class);
+
+        $thing       = new Thing();
+        $thing->date = new DateTimeImmutable('2021-01-01 00:00:00', new DateTimeZone('Africa/Tripoli'));
+
+        $this->dm->persist($thing);
+        $this->dm->flush();
+        $this->dm->clear();
+
+        $result = $this->dm->find(Thing::class, $thing->id);
+        $this->assertEquals($thing->date, $result->date);
+        $this->assertEquals('Africa/Tripoli', $result->date->getTimezone()->getName());
+
+        // Ensure we don't need to handle null values
+        $nothing = new Thing();
+
+        $this->dm->persist($nothing);
+        $this->dm->flush();
+        $this->dm->clear();
+
+        $result = $this->dm->find(Thing::class, $nothing->id);
+        $this->assertNull($result->date);
+    }
+}

tests/Documentation/CustomMapping/DateTimeWithTimezoneType.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Documentation\CustomMapping;
+
+use DateTimeImmutable;
+use DateTimeInterface;
+use DateTimeZone;
+use Doctrine\ODM\MongoDB\Types\ClosureToPHP;
+use Doctrine\ODM\MongoDB\Types\Type;
+use MongoDB\BSON\UTCDateTime;
+use RuntimeException;
+
+class DateTimeWithTimezoneType extends Type
+{
+    // This trait provides default closureToPHP used during data hydration
+    use ClosureToPHP;
+
+    /** @param array{utc: UTCDateTime, tz: string} $value */
+    public function convertToPHPValue($value): DateTimeImmutable
+    {
+        if (! isset($value['utc'], $value['tz'])) {
+            throw new RuntimeException('Database value cannot be converted to date with timezone. Expected array with "utc" and "tz" keys.');
+        }
+
+        $timeZone = new DateTimeZone($value['tz']);
+        $dateTime = $value['utc']
+            ->toDateTime()
+            ->setTimeZone($timeZone);
+
+        return DateTimeImmutable::createFromMutable($dateTime);
+    }
+
+    /**
+     * @param DateTimeInterface $value
+     *
+     * @return array{utc: UTCDateTime, tz: string}
+     */
+    public function convertToDatabaseValue($value): array
+    {
+        return [
+            'utc' => new UTCDateTime($value),
+            'tz' => $value->getTimezone()->getName(),
+        ];
+    }
+}

tests/Documentation/CustomMapping/Thing.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Documentation\CustomMapping;
+
+use DateTimeImmutable;
+use Doctrine\ODM\MongoDB\Mapping\Annotations\Document;
+use Doctrine\ODM\MongoDB\Mapping\Annotations\Field;
+use Doctrine\ODM\MongoDB\Mapping\Annotations\Id;
+
+#[Document]
+class Thing
+{
+    #[Id]
+    public string $id;
+
+    #[Field(type: 'date_with_timezone')]
+    public ?DateTimeImmutable $date = null;
+}