Added classes for defining relationships

2025-10-26 07:56:07 +01:00 · 2022-04-28 13:55:25 +03:00
parent 6218a4b366
commit 6ba1cff114
20 changed files with 1851 additions and 55 deletions
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
    "homepage": "https://getgrav.org",
    "license": "MIT",
    "require": {
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+        "php": "^7.4.1 || ^8.0",
        "ext-json": "*",
        "ext-openssl": "*",
        "ext-curl": "*",
@@ -89,7 +89,7 @@
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+            "php": "7.4.1"
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--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
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        "This file is @generated automatically"
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@@ -1655,20 +1655,20 @@
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@@ -1697,9 +1697,9 @@
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-                "source": "https://github.com/php-fig/container/tree/1.1.1"
+                "source": "https://github.com/php-fig/container/tree/1.1.2"
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-            "time": "2021-03-05T17:36:06+00:00"
+            "time": "2021-11-05T16:50:12+00:00"
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@@ -2224,16 +2224,16 @@
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+            "version": "v4.4.41",
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@@ -2294,7 +2294,7 @@
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@@ -2310,7 +2310,7 @@
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+            "time": "2022-04-12T15:19:55+00:00"
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@@ -2492,16 +2492,16 @@
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@@ -2553,7 +2553,7 @@
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            "support": {
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+                "source": "https://github.com/symfony/http-client/tree/v4.4.41"
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@@ -2569,7 +2569,7 @@
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@@ -3063,16 +3063,16 @@
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+            "version": "v4.4.41",
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@@ -3105,7 +3105,7 @@
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-                "source": "https://github.com/symfony/process/tree/v4.4.40"
+                "source": "https://github.com/symfony/process/tree/v4.4.41"
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@@ -3121,20 +3121,20 @@
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-            "time": "2022-03-18T16:18:39+00:00"
+            "time": "2022-04-04T10:19:07+00:00"
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        {
            "name": "symfony/var-dumper",
-            "version": "v4.4.39",
+            "version": "v4.4.41",
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@@ -3194,7 +3194,7 @@
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+                "source": "https://github.com/symfony/var-dumper/tree/v4.4.41"
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@@ -3210,7 +3210,7 @@
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@@ -3862,20 +3862,24 @@
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-            "version": "3.7.0",
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+                "php": "^7.4 | ^8.0",
+                "phpunit/phpunit": "^8.4 | ^9.0 | ^10.0 | 10.0.x-dev"
+            },
+            "require-dev": {
+                "consolidation/robo": "^3.0"
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@@ -3890,9 +3894,9 @@
            "description": "Flexible Stub wrapper for PHPUnit's Mock Builder",
            "support": {
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-                "source": "https://github.com/Codeception/Stub/tree/3.7.0"
+                "source": "https://github.com/Codeception/Stub/tree/4.0.2"
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-            "time": "2020-07-03T15:54:43+00:00"
+            "time": "2022-01-31T19:25:15+00:00"
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@@ -4679,16 +4683,16 @@
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            "name": "phpstan/phpstan",
-            "version": "1.6.0",
+            "version": "1.6.2",
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                "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "b480ba2ae0699a72d43a340c20b9c00ede91ee3e"
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@@ -4714,7 +4718,7 @@
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-                "source": "https://github.com/phpstan/phpstan/tree/1.6.0"
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@@ -4734,7 +4738,7 @@
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+            "time": "2022-04-27T11:05:24+00:00"
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@@ -6505,16 +6509,16 @@
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        {
            "name": "symfony/finder",
-            "version": "v5.4.3",
+            "version": "v5.4.8",
            "source": {
                "type": "git",
                "url": "https://github.com/symfony/finder.git",
-                "reference": "231313534dded84c7ecaa79d14bc5da4ccb69b7d"
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@@ -6548,7 +6552,7 @@
            "description": "Finds files and directories via an intuitive fluent interface",
            "homepage": "https://symfony.com",
            "support": {
-                "source": "https://github.com/symfony/finder/tree/v5.4.3"
+                "source": "https://github.com/symfony/finder/tree/v5.4.8"
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@@ -6564,7 +6568,7 @@
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-            "time": "2022-01-26T16:34:36+00:00"
+            "time": "2022-04-15T08:07:45+00:00"
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        {
            "name": "theseer/tokenizer",
@@ -6681,7 +6685,7 @@
    "prefer-stable": false,
    "prefer-lowest": false,
    "platform": {
-        "php": "^7.3.6 || ^8.0",
+        "php": "^7.4.1 || ^8.0",
        "ext-json": "*",
        "ext-openssl": "*",
        "ext-curl": "*",
@@ -6691,7 +6695,7 @@
    },
    "platform-dev": [],
    "platform-overrides": {
-        "php": "7.3.6"
+        "php": "7.4.1"
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 }
--- a/system/src/Grav/Common/Media/Interfaces/MediaObjectInterface.php
+++ b/system/src/Grav/Common/Media/Interfaces/MediaObjectInterface.php
@@ -50,6 +50,13 @@ interface MediaObjectInterface extends \Grav\Framework\Media\Interfaces\MediaObj
     */
    public function metadata();

+    /**
+     * Returns an array containing the file metadata
+     *
+     * @return array
+     */
+    public function getMeta();
+
    /**
     * Add meta file for the medium.
     *
--- a/system/src/Grav/Framework/Contracts/Media/MediaObjectInterface.php
+++ b/system/src/Grav/Framework/Contracts/Media/MediaObjectInterface.php
@@ -0,0 +1,52 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Media;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * Media Object Interface
+ */
+interface MediaObjectInterface extends IdentifierInterface
+{
+    /**
+     * Returns true if the object exists.
+     *
+     * @return bool
+     * @phpstan-pure
+     */
+    public function exists(): bool;
+
+    /**
+     * Get metadata associated to the media object.
+     *
+     * @return array
+     * @phpstan-pure
+     */
+    public function getMeta(): array;
+
+    /**
+     * @param string $field
+     * @return mixed
+     * @phpstan-pure
+     */
+    public function get(string $field);
+
+    /**
+     * Return URL pointing to the media object.
+     *
+     * @return string
+     * @phpstan-pure
+     */
+    public function getUrl(): string;
+
+    /**
+     * Create media response.
+     *
+     * @param array $actions
+     * @return ResponseInterface
+     * @phpstan-pure
+     */
+    public function createResponse(array $actions): ResponseInterface;
+}
--- a/system/src/Grav/Framework/Contracts/Object/IdentifierInterface.php
+++ b/system/src/Grav/Framework/Contracts/Object/IdentifierInterface.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Object;
+
+use JsonSerializable;
+
+/**
+ * Interface IdentifierInterface
+ */
+interface IdentifierInterface extends JsonSerializable
+{
+    /**
+     * Get identifier's ID.
+     *
+     * @return string
+     * @phpstan-pure
+     */
+    public function getId(): string;
+
+    /**
+     * Get identifier's type.
+     *
+     * @return string
+     * @phpstan-pure
+     */
+    public function getType(): string;
+}
--- a/system/src/Grav/Framework/Contracts/Relationships/RelationshipIdentifierInterface.php
+++ b/system/src/Grav/Framework/Contracts/Relationships/RelationshipIdentifierInterface.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Relationships;
+
+use ArrayAccess;
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+
+/**
+ * Interface RelationshipIdentifierInterface
+ */
+interface RelationshipIdentifierInterface extends IdentifierInterface
+{
+    /**
+     * If identifier has meta.
+     *
+     * @return bool
+     * @phpstan-pure
+     */
+    public function hasIdentifierMeta(): bool;
+
+    /**
+     * Get identifier meta.
+     *
+     * @return array|ArrayAccess
+     * @phpstan-pure
+     */
+    public function getIdentifierMeta();
+}
--- a/system/src/Grav/Framework/Contracts/Relationships/RelationshipInterface.php
+++ b/system/src/Grav/Framework/Contracts/Relationships/RelationshipInterface.php
@@ -0,0 +1,80 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Relationships;
+
+use Countable;
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use IteratorAggregate;
+use JsonSerializable;
+use Serializable;
+
+/**
+ * Interface Relationship
+ *
+ * @template T of IdentifierInterface
+ * @template P of IdentifierInterface
+ */
+interface RelationshipInterface extends Countable, IteratorAggregate, JsonSerializable, Serializable
+{
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getName(): string;
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getType(): string;
+
+    /**
+     * @return bool
+     * @phpstan-pure
+     */
+    public function isModified(): bool;
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getCardinality(): string;
+
+    /**
+     * @return P
+     * @phpstan-pure
+     */
+    public function getParent(): IdentifierInterface;
+
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return bool
+     * @phpstan-pure
+     */
+    public function has(string $id, string $type = null): bool;
+
+    /**
+     * @param T $identifier
+     * @return bool
+     * @phpstan-pure
+     */
+    public function hasIdentifier(IdentifierInterface $identifier): bool;
+
+    /**
+     * @param T $identifier
+     * @return bool
+     */
+    public function addIdentifier(IdentifierInterface $identifier): bool;
+
+    /**
+     * @param T|null $identifier
+     * @return bool
+     */
+    public function removeIdentifier(IdentifierInterface $identifier = null): bool;
+
+    /**
+     * @return iterable<T>
+     */
+    public function getIterator(): iterable;
+}
--- a/system/src/Grav/Framework/Contracts/Relationships/RelationshipsInterface.php
+++ b/system/src/Grav/Framework/Contracts/Relationships/RelationshipsInterface.php
@@ -0,0 +1,48 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Relationships;
+
+use ArrayAccess;
+use Countable;
+use Iterator;
+use JsonSerializable;
+
+/**
+ * Interface RelationshipsInterface
+ */
+interface RelationshipsInterface extends Countable, ArrayAccess, Iterator, JsonSerializable
+{
+    /**
+     * @return bool
+     * @phpstan-pure
+     */
+    public function isModified(): bool;
+
+    /**
+     * @return array
+     */
+    public function getModified(): array;
+
+    /**
+     * @return int
+     * @phpstan-pure
+     */
+    public function count(): int;
+
+    /**
+     * @param string $offset
+     * @return RelationshipInterface|null
+     */
+    public function offsetGet($offset): ?RelationshipInterface;
+
+    /**
+     * @return RelationshipInterface|null
+     */
+    public function current(): ?RelationshipInterface;
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function key(): string;
+}
--- a/system/src/Grav/Framework/Contracts/Relationships/ToManyRelationshipInterface.php
+++ b/system/src/Grav/Framework/Contracts/Relationships/ToManyRelationshipInterface.php
@@ -0,0 +1,49 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Relationships;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+
+/**
+ * Interface ToManyRelationshipInterface
+ *
+ * @template T of IdentifierInterface
+ * @template P of IdentifierInterface
+ * @template-extends RelationshipInterface<T,P>
+ */
+interface ToManyRelationshipInterface extends RelationshipInterface
+{
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return T|null
+     * @phpstan-pure
+     */
+    public function getIdentifier(string $id, string $type = null): ?IdentifierInterface;
+
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return T|null
+     * @phpstan-pure
+     */
+    public function getObject(string $id, string $type = null): ?object;
+
+    /**
+     * @param iterable<T> $identifiers
+     * @return bool
+     */
+    public function addIdentifiers(iterable $identifiers): bool;
+
+    /**
+     * @param iterable<T> $identifiers
+     * @return bool
+     */
+    public function replaceIdentifiers(iterable $identifiers): bool;
+
+    /**
+     * @param iterable<T> $identifiers
+     * @return bool
+     */
+    public function removeIdentifiers(iterable $identifiers): bool;
+}
--- a/system/src/Grav/Framework/Contracts/Relationships/ToOneRelationshipInterface.php
+++ b/system/src/Grav/Framework/Contracts/Relationships/ToOneRelationshipInterface.php
@@ -0,0 +1,37 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Contracts\Relationships;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+
+/**
+ * Interface ToOneRelationshipInterface
+ *
+ * @template T of IdentifierInterface
+ * @template P of IdentifierInterface
+ * @template-extends RelationshipInterface<T,P>
+ */
+interface ToOneRelationshipInterface extends RelationshipInterface
+{
+    /**
+     * @param string|null $id
+     * @param string|null $type
+     * @return T|null
+     * @phpstan-pure
+     */
+    public function getIdentifier(string $id = null, string $type = null): ?IdentifierInterface;
+
+    /**
+     * @param string|null $id
+     * @param string|null $type
+     * @return T|null
+     * @phpstan-pure
+     */
+    public function getObject(string $id = null, string $type = null): ?object;
+
+    /**
+     * @param T|null $identifier
+     * @return bool
+     */
+    public function replaceIdentifier(IdentifierInterface $identifier = null): bool;
+}
--- a/system/src/Grav/Framework/Flex/FlexIdentifier.php
+++ b/system/src/Grav/Framework/Flex/FlexIdentifier.php
@@ -0,0 +1,72 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Flex;
+
+use Grav\Common\Grav;
+use Grav\Framework\Flex\Interfaces\FlexObjectInterface;
+use Grav\Framework\Object\Identifiers\Identifier;
+use RuntimeException;
+
+/**
+ * Interface IdentifierInterface
+ *
+ * @template T of FlexObjectInterface
+ */
+class FlexIdentifier extends Identifier
+{
+    private string $keyField;
+    private ?FlexObjectInterface $object = null;
+
+    /**
+     * @param FlexObjectInterface $object
+     * @return FlexIdentifier
+     */
+    public static function createFromObject(FlexObjectInterface $object): FlexIdentifier
+    {
+        $instance = new static($object->getKey(), $object->getFlexType(), 'key');
+        $instance->setObject($object);
+
+        return $instance;
+    }
+
+    /**
+     * IdentifierInterface constructor.
+     * @param string $id
+     * @param string $type
+     * @param string $keyField
+     */
+    public function __construct(string $id, string $type, string $keyField = 'key')
+    {
+        parent::__construct($id, $type);
+
+        $this->keyField = $keyField;
+    }
+
+    /**
+     * @return T
+     */
+    public function getObject(): ?FlexObjectInterface
+    {
+        if (!isset($this->object)) {
+            /** @var Flex $flex */
+            $flex = Grav::instance()['flex'];
+
+            $this->object = $flex->getObject($this->getId(), $this->getType(), $this->keyField);
+        }
+
+        return $this->object;
+    }
+
+    /**
+     * @param T $object
+     */
+    public function setObject(FlexObjectInterface $object): void
+    {
+        $type = $this->getType();
+        if ($type !== $object->getFlexType()) {
+            throw new RuntimeException(sprintf('Object has to be type %s, %s given', $type, $object->getFlexType()));
+        }
+
+        $this->object = $object;
+    }
+}
--- a/system/src/Grav/Framework/Flex/Traits/FlexRelationshipsTrait.php
+++ b/system/src/Grav/Framework/Flex/Traits/FlexRelationshipsTrait.php
@@ -0,0 +1,43 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Flex\Traits;
+
+use Grav\Framework\Contracts\Relationships\RelationshipInterface;
+use Grav\Framework\Contracts\Relationships\RelationshipsInterface;
+use Grav\Framework\Flex\FlexIdentifier;
+use Grav\Framework\Relationships\Relationships;
+
+trait FlexRelationshipsTrait
+{
+    private ?RelationshipsInterface $_relationships = null;
+
+    /**
+     * @return Relationships
+     */
+    public function getRelationships(): Relationships
+    {
+        if (!isset($this->_relationships)) {
+            $blueprint = $this->getBlueprint();
+            $options = $blueprint->get('config/relationships', []);
+            $parent = FlexIdentifier::createFromObject($this);
+
+            $this->_relationships = new Relationships($parent, $options);
+        }
+
+        return $this->_relationships;
+    }
+
+    /**
+     * @param string $name
+     * @return RelationshipInterface|null
+     */
+    public function getRelationship(string $name): ?RelationshipInterface
+    {
+        return $this->getRelationships()[$name];
+    }
+
+    protected function resetRelationships(): void
+    {
+        $this->_relationships = null;
+    }
+}
--- a/system/src/Grav/Framework/Media/MediaIdentifier.php
+++ b/system/src/Grav/Framework/Media/MediaIdentifier.php
@@ -0,0 +1,135 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Media;
+
+use Grav\Common\Grav;
+use Grav\Common\User\Interfaces\UserInterface;
+use Grav\Framework\Contracts\Media\MediaObjectInterface;
+use Grav\Framework\Flex\Flex;
+use Grav\Framework\Flex\FlexFormFlash;
+use Grav\Framework\Flex\Interfaces\FlexObjectInterface;
+use Grav\Framework\Object\Identifiers\Identifier;
+
+/**
+ * Interface IdentifierInterface
+ *
+ * @template T of MediaObjectInterface
+ */
+class MediaIdentifier extends Identifier
+{
+    private ?MediaObjectInterface $object = null;
+
+    /**
+     * @param MediaObjectInterface $object
+     * @return MediaIdentifier
+     */
+    public static function createFromObject(MediaObjectInterface $object): MediaIdentifier
+    {
+        $instance = new static($object->getId());
+        $instance->setObject($object);
+
+        return $instance;
+    }
+
+    /**
+     * @param string $id
+     */
+    public function __construct(string $id)
+    {
+        parent::__construct($id, 'media');
+    }
+
+    /**
+     * @return T
+     */
+    public function getObject(): ?MediaObjectInterface
+    {
+        if (!isset($this->object)) {
+            $type = $this->getType();
+            $id = $this->getId();
+
+            $parts = explode('/', $id);
+            if ($type === 'media' && str_starts_with($id, 'uploads/')) {
+                array_shift($parts);
+                $type = array_shift($parts);
+                $uniqueId = array_shift($parts);
+                $field = array_shift($parts);
+                $filename = implode('/', $parts);
+
+                $flash = $this->getFlash($type, $uniqueId);
+                if ($flash->exists()) {
+                    $uploadedFile = $flash->getFilesByField($field)[$filename] ?? null;
+
+                    $this->object = new UploadedMediaObject($field, $filename, $flash, $uploadedFile);
+                }
+            } else {
+                $type = array_shift($parts);
+                $key = array_shift($parts);
+                $field = array_shift($parts);
+                $filename = implode('/', $parts);
+
+                $flexObject = $this->getFlexObject($type, $key);
+                if ($flexObject && method_exists($flexObject, 'getMediaField') && method_exists($flexObject, 'getMedia')) {
+                    $media = $field !== 'media' ? $flexObject->getMediaField($field) : $flexObject->getMedia();
+                    $image = null;
+                    if ($media) {
+                        $image = $media[$filename];
+                    }
+
+                    $this->object = new MediaObject($field, $filename, $image, $flexObject);
+                }
+            }
+
+            if (!isset($this->object)) {
+                throw new \RuntimeException(sprintf('Object not found for identifier {type: "%s", id: "%s"}', $type, $id));
+            }
+        }
+
+        return $this->object;
+    }
+
+    /**
+     * @param T $object
+     */
+    public function setObject(MediaObjectInterface $object): void
+    {
+        $type = $this->getType();
+        $objectType = $object->getType();
+
+        if ($type !== $objectType) {
+            throw new \RuntimeException(sprintf('Object has to be type %s, %s given', $type, $objectType));
+        }
+
+        $this->object = $object;
+    }
+
+    protected function getFlash(string $type, string $uniqueId): FlexFormFlash
+    {
+        /** @var UserInterface|null $user */
+        $user = Grav::instance()['user'] ?? null;
+        if (null !== $user && $user->exists()) {
+            // TODO: Modify uniqueid so we can detect if flash is user or session based.
+            $mediaFolder = $user->getMediaFolder();
+        } else {
+            // TODO: Implement session based flash.
+            throw new \RuntimeException('Not implemented');
+        }
+
+        $folder = "{$mediaFolder}/tmp/api/flex-{$type}";
+
+        $config = [
+            'unique_id' => $uniqueId,
+            'folder' => $folder
+        ];
+
+        return new FlexFormFlash($config);
+    }
+
+    protected function getFlexObject(string $type, string $key): ?FlexObjectInterface
+    {
+        /** @var Flex $flex */
+        $flex = Grav::instance()['flex'];
+
+        return $flex->getObject($key, $type);
+    }
+}
--- a/system/src/Grav/Framework/Media/MediaObject.php
+++ b/system/src/Grav/Framework/Media/MediaObject.php
@@ -0,0 +1,210 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Media;
+
+use Grav\Common\Media\Interfaces\MediaObjectInterface as GravMediaObjectInterface;
+use Grav\Common\Page\Medium\ImageMedium;
+use Grav\Framework\Contracts\Media\MediaObjectInterface;
+use Grav\Framework\Flex\Interfaces\FlexObjectInterface;
+use Grav\Framework\Psr7\Response;
+use Throwable;
+
+/**
+ * Class MediaObject
+ */
+class MediaObject implements MediaObjectInterface
+{
+    // FIXME:
+    static public string $placeholderImage = 'theme://img/revkit-temp.svg';
+
+    public FlexObjectInterface $object;
+    public ?GravMediaObjectInterface $media;
+
+    private ?string $field;
+    private string $filename;
+
+    /**
+     * MediaObject constructor.
+     * @param string|null $field
+     * @param string $filename
+     * @param GravMediaObjectInterface|null $media
+     * @param FlexObjectInterface $object
+     */
+    public function __construct(?string $field, string $filename, ?GravMediaObjectInterface $media, FlexObjectInterface $object)
+    {
+        $this->field = $field;
+        $this->filename = $filename;
+        $this->media = $media;
+        $this->object = $object;
+    }
+
+    /**
+     * @return string
+     */
+    public function getType(): string
+    {
+        return 'media';
+    }
+
+    /**
+     * @return string
+     */
+    public function getId(): string
+    {
+        $field = $this->field;
+        $object = $this->object;
+        $path = $field ? "/{$field}/" : '/media/';
+
+        return $object->getType() . '/' . $object->getKey() . $path . basename($this->filename);
+    }
+
+    /**
+     * @return bool
+     */
+    public function exists(): bool
+    {
+        return $this->media !== null;
+    }
+
+    /**
+     * @return array
+     */
+    public function getMeta(): array
+    {
+        if (!isset($this->media)) {
+            return [];
+        }
+
+        return $this->media->getMeta();
+    }
+
+    /**
+     * @param string $field
+     * @return mixed|null
+     */
+    public function get(string $field)
+    {
+        if (!isset($this->media)) {
+            return null;
+        }
+
+        return $this->media->get($field);
+    }
+
+    /**
+     * @return string
+     */
+    public function getUrl(): string
+    {
+        if (!isset($this->media)) {
+            return '';
+        }
+
+        return $this->media->url();
+    }
+
+    /**
+     * Create media response.
+     *
+     * @param array $actions
+     * @return Response
+     */
+    public function createResponse(array $actions): Response
+    {
+        if (!isset($this->media)) {
+            return $this->create404Response($actions);
+        }
+
+        $media = $this->media;
+
+        if ($actions) {
+            $media = $this->processMediaActions($media, $actions);
+        }
+
+        // FIXME: This only works for images
+        if (!$media instanceof ImageMedium) {
+            throw new \RuntimeException('Not Implemented', 500);
+        }
+
+        $filename = $media->path(false);
+        $time = filemtime($filename);
+        $size = filesize($filename);
+        $body = fopen($filename, 'rb');
+        $headers = [
+            'Content-Type' => $media->get('mime'),
+            'Last-Modified' => gmdate('D, d M Y H:i:s', $time) . ' GMT',
+            'ETag' => sprintf('%x-%x', $size, $time)
+        ];
+
+        return new Response(200, $headers, $body);
+    }
+
+    /**
+     * Process media actions
+     *
+     * @param GravMediaObjectInterface $medium
+     * @param array $actions
+     * @return GravMediaObjectInterface
+     */
+    protected function processMediaActions(GravMediaObjectInterface $medium, array $actions): GravMediaObjectInterface
+    {
+        // loop through actions for the image and call them
+        foreach ($actions as $method => $params) {
+            $matches = [];
+
+            if (preg_match('/\[(.*)]/', $params, $matches)) {
+                $args = [explode(',', $matches[1])];
+            } else {
+                $args = explode(',', $params);
+            }
+
+            try {
+                $medium->{$method}(...$args);
+            } catch (Throwable $e) {
+                // Ignore all errors for now and just skip the action.
+            }
+        }
+
+        return $medium;
+    }
+
+    /**
+     * @param array $actions
+     * @return Response
+     */
+    protected function create404Response(array $actions): Response
+    {
+        // Display placeholder image.
+        $filename = static::$placeholderImage;
+
+        $time = filemtime($filename);
+        $size = filesize($filename);
+        $body = fopen($filename, 'rb');
+        $headers = [
+            'Content-Type' => 'image/svg',
+            'Last-Modified' => gmdate('D, d M Y H:i:s', $time) . ' GMT',
+            'ETag' => sprintf('%x-%x', $size, $time)
+        ];
+
+        return new Response(404, $headers, $body);
+    }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'type' => $this->getType(),
+            'id' => $this->getId()
+        ];
+    }
+
+    /**
+     * @return string[]
+     */
+    public function __debugInfo(): array
+    {
+        return $this->jsonSerialize();
+    }
+}
--- a/system/src/Grav/Framework/Media/UploadedMediaObject.php
+++ b/system/src/Grav/Framework/Media/UploadedMediaObject.php
@@ -0,0 +1,158 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Media;
+
+use Grav\Framework\Contracts\Media\MediaObjectInterface;
+use Grav\Framework\Flex\FlexFormFlash;
+use Grav\Framework\Form\Interfaces\FormFlashInterface;
+use Grav\Framework\Psr7\Response;
+use Psr\Http\Message\UploadedFileInterface;
+
+/**
+ * Class UploadedMediaObject
+ */
+class UploadedMediaObject implements MediaObjectInterface
+{
+    // FIXME:
+    static public string $placeholderImage = 'theme://img/revkit-temp.svg';
+
+    public FormFlashInterface $object;
+
+    private ?string $field;
+    private string $filename;
+    private array $meta;
+    private ?UploadedFileInterface $uploadedFile;
+
+    /**
+     * UploadedMediaObject constructor.
+     * @param string|null $field
+     * @param string $filename
+     * @param FormFlashInterface $object
+     * @param UploadedFileInterface|null $uploadedFile
+     */
+    public function __construct(?string $field, string $filename, FormFlashInterface $object, ?UploadedFileInterface $uploadedFile = null)
+    {
+        $this->field = $field;
+        $this->filename = $filename;
+        $this->object = $object;
+        $this->uploadedFile = $uploadedFile;
+        if ($uploadedFile) {
+            $this->meta = [
+                'filename' => $uploadedFile->getClientFilename(),
+                'mime' => $uploadedFile->getClientMediaType(),
+                'size' => $uploadedFile->getSize()
+            ];
+        } else {
+            $this->meta = [];
+        }
+    }
+
+    /**
+     * @return string
+     */
+    public function getType(): string
+    {
+        return 'media';
+    }
+
+    /**
+     * @return string
+     */
+    public function getId(): string
+    {
+        $field = $this->field;
+        $object = $this->object;
+        if ($object instanceof FlexFormFlash) {
+            $type = $object->getObject()->getFlexType();
+        } else {
+            $type = 'undefined';
+        }
+
+        $id = $type . '/' . $object->getUniqueId();
+        $path = $field ? "/{$field}/" : '';
+
+        return 'uploads/' . $id . $path . basename($this->filename);
+    }
+
+    /**
+     * @return bool
+     */
+    public function exists(): bool
+    {
+        //return $this->uploadedFile !== null;
+        return false;
+    }
+
+    /**
+     * @return array
+     */
+    public function getMeta(): array
+    {
+        return $this->meta;
+    }
+
+    /**
+     * @param string $field
+     * @return mixed|null
+     */
+    public function get(string $field)
+    {
+        return $this->meta[$field] ?? null;
+    }
+
+    /**
+     * @return string
+     */
+    public function getUrl(): string
+    {
+        return '';
+    }
+
+    /**
+     * @return UploadedFileInterface|null
+     */
+    public function getUploadedFile(): ?UploadedFileInterface
+    {
+        return $this->uploadedFile;
+    }
+
+    /**
+     * @param array $actions
+     * @return Response
+     */
+    public function createResponse(array $actions): Response
+    {
+        // Display placeholder image.
+        $filename = static::$placeholderImage;
+
+        $time = filemtime($filename);
+        $size = filesize($filename);
+        $body = fopen($filename, 'rb');
+        $headers = [
+            'Content-Type' => 'image/svg',
+            'Last-Modified' => gmdate('D, d M Y H:i:s', $time) . ' GMT',
+            'ETag' => sprintf('%x-%x', $size, $time)
+        ];
+
+        return new Response(404, $headers, $body);
+    }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'type' => $this->getType(),
+            'id' => $this->getId()
+        ];
+    }
+
+    /**
+     * @return string[]
+     */
+    public function __debugInfo(): array
+    {
+        return $this->jsonSerialize();
+    }
+}
--- a/system/src/Grav/Framework/Object/Identifiers/Identifier.php
+++ b/system/src/Grav/Framework/Object/Identifiers/Identifier.php
@@ -0,0 +1,64 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Object\Identifiers;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+
+/**
+ * Interface IdentifierInterface
+ *
+ * @template T of object
+ */
+class Identifier implements IdentifierInterface
+{
+    private string $id;
+    private string $type;
+
+    /**
+     * IdentifierInterface constructor.
+     * @param string $id
+     * @param string $type
+     */
+    public function __construct(string $id, string $type)
+    {
+        $this->id = $id;
+        $this->type = $type;
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getId(): string
+    {
+        return $this->id;
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getType(): string
+    {
+        return $this->type;
+    }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'type' => $this->type,
+            'id' => $this->id
+        ];
+    }
+
+    /**
+     * @return array
+     */
+    public function __debugInfo(): array
+    {
+        return $this->jsonSerialize();
+    }
+}
--- a/system/src/Grav/Framework/Relationships/Relationships.php
+++ b/system/src/Grav/Framework/Relationships/Relationships.php
@@ -0,0 +1,211 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Relationships;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use Grav\Framework\Contracts\Relationships\RelationshipInterface;
+use Grav\Framework\Contracts\Relationships\RelationshipsInterface;
+use Grav\Framework\Flex\FlexIdentifier;
+use RuntimeException;
+use function count;
+
+/**
+ * Class Relationships
+ */
+class Relationships implements RelationshipsInterface
+{
+    protected IdentifierInterface $parent;
+    protected array $options;
+
+    /** @var RelationshipInterface[] */
+    protected array $relationships;
+
+    /**
+     * Relationships constructor.
+     * @param IdentifierInterface $parent
+     * @param array $options
+     */
+    public function __construct(IdentifierInterface $parent, array $options)
+    {
+        $this->parent = $parent;
+        $this->options = $options;
+        $this->relationships = [];
+    }
+
+    /**
+     * @return bool
+     * @phpstan-pure
+     */
+    public function isModified(): bool
+    {
+        return !empty($this->getModified());
+    }
+
+    /**
+     * @return RelationshipInterface[]
+     * @phpstan-pure
+     */
+    public function getModified(): array
+    {
+        $list = [];
+        foreach ($this->relationships as $name => $relationship) {
+            if ($relationship->isModified()) {
+                $list[$name] = $relationship;
+            }
+        }
+
+        return $list;
+    }
+
+    /**
+     * @return int
+     * @phpstan-pure
+     */
+    public function count(): int
+    {
+        return count($this->options);
+    }
+
+    /**
+     * @param string $offset
+     * @return bool
+     * @phpstan-pure
+     */
+    public function offsetExists($offset): bool
+    {
+        return isset($this->options[$offset]);
+    }
+
+    /**
+     * @param string $offset
+     * @return RelationshipInterface|null
+     */
+    public function offsetGet($offset): ?RelationshipInterface
+    {
+        if (!isset($this->relationships[$offset])) {
+            $options = $this->options[$offset] ?? null;
+            if (null === $options) {
+                return null;
+            }
+
+            $this->relationships[$offset] = $this->createRelationship($offset, $options);
+        }
+
+        return $this->relationships[$offset];
+    }
+
+    /**
+     * @param string $offset
+     * @param mixed $value
+     * @return never-return
+     */
+    public function offsetSet($offset, $value)
+    {
+        throw new RuntimeException('Setting relationship is not supported', 500);
+    }
+
+    /**
+     * @param string $offset
+     * @return never-return
+     */
+    public function offsetUnset($offset)
+    {
+        throw new RuntimeException('Removing relationship is not allowed', 500);
+    }
+
+    /**
+     * @return RelationshipInterface|null
+     */
+    public function current(): ?RelationshipInterface
+    {
+        $name = key($this->options);
+        if ($name === null) {
+            return null;
+        }
+
+        return $this->offsetGet($name);
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function key(): string
+    {
+        return key($this->options);
+    }
+
+    /**
+     * @return void
+     * @phpstan-pure
+     */
+    public function next(): void
+    {
+        next($this->options);
+    }
+
+    /**
+     * @return void
+     * @phpstan-pure
+     */
+    public function rewind(): void
+    {
+        reset($this->options);
+    }
+
+    /**
+     * @return bool
+     * @phpstan-pure
+     */
+    public function valid(): bool
+    {
+        return key($this->options) !== null;
+    }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize(): array
+    {
+        $list = [];
+        foreach ($this as $name => $relationship) {
+            $list[$name] = $relationship->jsonSerialize();
+        }
+
+        return $list;
+    }
+
+    /**
+     * @param string $name
+     * @param array $options
+     * @return RelationshipInterface
+     */
+    private function createRelationship(string $name, array $options): RelationshipInterface
+    {
+        $data = null;
+
+        $parent = $this->parent;
+        if ($parent instanceof FlexIdentifier) {
+            $object = $parent->getObject();
+            if (!method_exists($object, 'initRelationship')) {
+                throw new RuntimeException(sprintf('Bad relationship %s', $name), 500);
+            }
+
+            $data = $object->initRelationship($name);
+        }
+
+        $cardinality = $options['cardinality'] ?? '';
+        switch ($cardinality) {
+            case 'to-one':
+                $relationship = new ToOneRelationship($parent, $name, $options, $data);
+                break;
+            case 'to-many':
+                $relationship = new ToManyRelationship($parent, $name, $options, $data ?? []);
+                break;
+            default:
+                throw new RuntimeException(sprintf('Bad relationship cardinality %s', $cardinality), 500);
+        }
+
+        return $relationship;
+    }
+}
--- a/system/src/Grav/Framework/Relationships/ToManyRelationship.php
+++ b/system/src/Grav/Framework/Relationships/ToManyRelationship.php
@@ -0,0 +1,244 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Relationships;
+
+use ArrayIterator;
+use Grav\Framework\Compat\Serializable;
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use Grav\Framework\Contracts\Relationships\ToManyRelationshipInterface;
+use Grav\Framework\Relationships\Traits\RelationshipTrait;
+use function count;
+use function is_callable;
+
+/**
+ * Class ToManyRelationship
+ *
+ * @template T of object
+ * @template P of object
+ * @template-implements ToManyRelationshipInterface<IdentifierInterface,IdentifierInterface>
+ */
+class ToManyRelationship implements ToManyRelationshipInterface
+{
+    /** @template-use RelationshipTrait<T> */
+    use RelationshipTrait;
+    use Serializable;
+
+    /** @var IdentifierInterface[] */
+    protected array $identifiers = [];
+
+    /**
+     * ToManyRelationship constructor.
+     * @param string $name
+     * @param IdentifierInterface $parent
+     * @param iterable<IdentifierInterface> $identifiers
+     */
+    public function __construct(IdentifierInterface $parent, string $name, array $options, iterable $identifiers = [])
+    {
+        $this->parent = $parent;
+        $this->name = $name;
+
+        $this->parseOptions($options);
+        $this->addIdentifiers($identifiers);
+
+        $this->modified = false;
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getCardinality(): string
+    {
+        return 'to-many';
+    }
+
+    /**
+     * @return int
+     * @phpstan-pure
+     */
+    public function count(): int
+    {
+        return count($this->identifiers);
+    }
+
+    /**
+     * @return array
+     */
+    public function fetch(): array
+    {
+        $list = [];
+        foreach ($this->identifiers as $identifier) {
+            if (is_callable([$identifier, 'getObject'])) {
+                $identifier = $identifier->getObject();
+            }
+            $list[] = $identifier;
+        }
+
+        return $list;
+    }
+
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return bool
+     * @phpstan-pure
+     */
+    public function has(string $id, string $type = null): bool
+    {
+        return $this->getIdentifier($id, $type) !== null;
+    }
+
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return IdentifierInterface|null
+     * @phpstan-pure
+     */
+    public function getIdentifier(string $id, string $type = null): ?IdentifierInterface
+    {
+        if (null === $type) {
+            $type = $this->getType();
+        }
+
+        if ($type === 'media' && !str_contains($id, '/')) {
+            $name = $this->name;
+            $id = $this->parent->getType() . '/' . $this->parent->getId() . '/'. $name . '/' . $id;
+        }
+
+        $key = "{$type}/{$id}";
+
+        return $this->identifiers[$key] ?? null;
+    }
+
+    /**
+     * @param string $id
+     * @param string|null $type
+     * @return T|null
+     */
+    public function getObject(string $id, string $type = null): ?object
+    {
+        $identifier = $this->getIdentifier($id, $type);
+        if ($identifier && is_callable([$identifier, 'getObject'])) {
+            $identifier = $identifier->getObject();
+        }
+
+        return $identifier;
+    }
+
+    /**
+     * @param IdentifierInterface $identifier
+     * @return bool
+     */
+    public function addIdentifier(IdentifierInterface $identifier): bool
+    {
+        return $this->addIdentifiers([$identifier]);
+    }
+
+    /**
+     * @param IdentifierInterface|null $identifier
+     * @return bool
+     */
+    public function removeIdentifier(IdentifierInterface $identifier = null): bool
+    {
+        return !$identifier || $this->removeIdentifiers([$identifier]);
+    }
+
+    /**
+     * @param iterable<IdentifierInterface> $identifiers
+     * @return bool
+     */
+    public function addIdentifiers(iterable $identifiers): bool
+    {
+        foreach ($identifiers as $identifier) {
+            $type = $identifier->getType();
+            $id = $identifier->getId();
+            $key = "{$type}/{$id}";
+
+            $this->identifiers[$key] = $this->checkIdentifier($identifier);
+            $this->modified = true;
+        }
+
+        return true;
+    }
+
+    /**
+     * @param iterable<IdentifierInterface> $identifiers
+     * @return bool
+     */
+    public function replaceIdentifiers(iterable $identifiers): bool
+    {
+        $this->identifiers = [];
+        $this->modified = true;
+
+        return $this->addIdentifiers($identifiers);
+    }
+
+    /**
+     * @param iterable<IdentifierInterface> $identifiers
+     * @return bool
+     */
+    public function removeIdentifiers(iterable $identifiers): bool
+    {
+        foreach ($identifiers as $identifier) {
+            $type = $identifier->getType();
+            $id = $identifier->getId();
+            $key = "{$type}/{$id}";
+
+            unset($this->identifiers[$key]);
+            $this->modified = true;
+        }
+
+        return true;
+    }
+
+    /**
+     * @return iterable<IdentifierInterface>
+     * @phpstan-pure
+     */
+    public function getIterator(): iterable
+    {
+        return new ArrayIterator($this->identifiers);
+    }
+
+    /**
+     * @return array
+     */
+    public function jsonSerialize(): array
+    {
+        $list = [];
+        foreach ($this->getIterator() as $item) {
+            $list[] = $item->jsonSerialize();
+        }
+
+        return $list;
+    }
+
+    /**
+     * @return array
+     */
+    public function __serialize(): array
+    {
+        return [
+            'parent' => $this->parent,
+            'name' => $this->name,
+            'type' => $this->type,
+            'options' => $this->options,
+            'modified' => $this->modified,
+            'identifiers' => $this->identifiers,
+        ];
+    }
+
+    /**
+     * @param array $data
+     * @return void
+     */
+    public function __unserialize(array $data): void
+    {
+        $this->parent = $data['parent'];
+        $this->name = $data['name'];
+        $this->type = $data['type'];
+        $this->options = $data['options'];
+        $this->modified = $data['modified'];
+        $this->identifiers = $data['identifiers'];
+    }
+}
--- a/system/src/Grav/Framework/Relationships/ToOneRelationship.php
+++ b/system/src/Grav/Framework/Relationships/ToOneRelationship.php
@@ -0,0 +1,205 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Relationships;
+
+use ArrayIterator;
+use Grav\Framework\Compat\Serializable;
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use Grav\Framework\Contracts\Relationships\ToOneRelationshipInterface;
+use Grav\Framework\Relationships\Traits\RelationshipTrait;
+use function is_callable;
+
+/**
+ * Class ToOneRelationship
+ *
+ * @template T of object
+ * @template-implements ToOneRelationshipInterface<IdentifierInterface,IdentifierInterface>
+ */
+class ToOneRelationship implements ToOneRelationshipInterface
+{
+    /** @template-use RelationshipTrait<T> */
+    use RelationshipTrait;
+    use Serializable;
+
+    protected ?IdentifierInterface $identifier = null;
+
+    public function __construct(IdentifierInterface $parent, string $name, array $options, IdentifierInterface $identifier = null)
+    {
+        $this->parent = $parent;
+        $this->name = $name;
+
+        $this->parseOptions($options);
+        $this->replaceIdentifier($identifier);
+
+        $this->modified = false;
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getCardinality(): string
+    {
+        return 'to-one';
+    }
+
+    /**
+     * @return int
+     * @phpstan-pure
+     */
+    public function count(): int
+    {
+        return $this->identifier ? 1 : 0;
+    }
+
+    /**
+     * @return object|null
+     */
+    public function fetch(): ?object
+    {
+        $identifier = $this->identifier;
+        if (is_callable([$identifier, 'getObject'])) {
+            $identifier = $identifier->getObject();
+        }
+
+        return $identifier;
+    }
+
+
+    /**
+     * @param string|null $id
+     * @param string|null $type
+     * @return bool
+     * @phpstan-pure
+     */
+    public function has(string $id = null, string $type = null): bool
+    {
+        return $this->getIdentifier($id, $type) !== null;
+    }
+
+    /**
+     * @param string|null $id
+     * @param string|null $type
+     * @return IdentifierInterface|null
+     * @phpstan-pure
+     */
+    public function getIdentifier(string $id = null, string $type = null): ?IdentifierInterface
+    {
+        if ($id && $this->getType() === 'media' && !str_contains($id, '/')) {
+            $name = $this->name;
+            $id = $this->parent->getType() . '/' . $this->parent->getId() . '/'. $name . '/' . $id;
+        }
+
+        $identifier = $this->identifier ?? null;
+        if (null === $identifier || ($type && $type !== $identifier->getType()) || ($id && $id !== $identifier->getId())) {
+            return null;
+        }
+
+        return $identifier;
+    }
+
+    /**
+     * @param string|null $id
+     * @param string|null $type
+     * @return T|null
+     */
+    public function getObject(string $id = null, string $type = null): ?object
+    {
+        $identifier = $this->getIdentifier($id, $type);
+        if ($identifier && is_callable([$identifier, 'getObject'])) {
+            $identifier = $identifier->getObject();
+        }
+
+        return $identifier;
+    }
+
+    /**
+     * @param IdentifierInterface $identifier
+     * @return bool
+     */
+    public function addIdentifier(IdentifierInterface $identifier): bool
+    {
+        $this->identifier = $this->checkIdentifier($identifier);
+        $this->modified = true;
+
+        return true;
+    }
+
+    /**
+     * @param IdentifierInterface|null $identifier
+     * @return bool
+     */
+    public function replaceIdentifier(IdentifierInterface $identifier = null): bool
+    {
+        if ($identifier === null) {
+            $this->identifier = null;
+            $this->modified = true;
+
+            return true;
+        }
+
+        return $this->addIdentifier($identifier);
+    }
+
+    /**
+     * @param IdentifierInterface|null $identifier
+     * @return bool
+     */
+    public function removeIdentifier(IdentifierInterface $identifier = null): bool
+    {
+        if (null === $identifier || $this->has($identifier->getId(), $identifier->getType())) {
+            $this->identifier = null;
+            $this->modified = true;
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @return iterable<IdentifierInterface>
+     * @phpstan-pure
+     */
+    public function getIterator(): iterable
+    {
+        return new ArrayIterator((array)$this->identifier);
+    }
+
+    /**
+     * @return array|null
+     */
+    public function jsonSerialize(): ?array
+    {
+        return $this->identifier ? $this->identifier->jsonSerialize() : null;
+    }
+
+    /**
+     * @return array
+     */
+    public function __serialize(): array
+    {
+        return [
+            'parent' => $this->parent,
+            'name' => $this->name,
+            'type' => $this->type,
+            'options' => $this->options,
+            'modified' => $this->modified,
+            'identifier' => $this->identifier,
+        ];
+    }
+
+    /**
+     * @param array $data
+     * @return void
+     */
+    public function __unserialize(array $data): void
+    {
+        $this->parent = $data['parent'];
+        $this->name = $data['name'];
+        $this->type = $data['type'];
+        $this->options = $data['options'];
+        $this->modified = $data['modified'];
+        $this->identifier = $data['identifier'];
+    }
+}
--- a/system/src/Grav/Framework/Relationships/Traits/RelationshipTrait.php
+++ b/system/src/Grav/Framework/Relationships/Traits/RelationshipTrait.php
@@ -0,0 +1,122 @@
+<?php declare(strict_types=1);
+
+namespace Grav\Framework\Relationships\Traits;
+
+use Grav\Framework\Contracts\Object\IdentifierInterface;
+use Grav\Framework\Flex\FlexIdentifier;
+use Grav\Framework\Media\MediaIdentifier;
+use Grav\Framework\Object\Identifiers\Identifier;
+use function get_class;
+
+/**
+ * Trait RelationshipTrait
+ *
+ * @template T of object
+ */
+trait RelationshipTrait
+{
+    protected IdentifierInterface $parent;
+    protected string $name;
+    protected string $type;
+    protected array $options;
+    protected bool $modified = false;
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    /**
+     * @return string
+     * @phpstan-pure
+     */
+    public function getType(): string
+    {
+        return $this->type;
+    }
+
+    /**
+     * @return bool
+     * @phpstan-pure
+     */
+    public function isModified(): bool
+    {
+        return $this->modified;
+    }
+
+    /**
+     * @return IdentifierInterface
+     * @phpstan-pure
+     */
+    public function getParent(): IdentifierInterface
+    {
+        return $this->parent;
+    }
+
+    /**
+     * @param IdentifierInterface $identifier
+     * @return bool
+     * @phpstan-pure
+     */
+    public function hasIdentifier(IdentifierInterface $identifier): bool
+    {
+        return $this->getIdentifier($identifier->getId(), $identifier->getType()) !== null;
+    }
+
+    /**
+     * @return int
+     * @phpstan-pure
+     */
+    abstract public function count(): int;
+
+    /**
+     * @return void
+     * @phpstan-pure
+     */
+    public function check(): void
+    {
+        $min = $this->options['min'] ?? 0;
+        $max = $this->options['max'] ?? 0;
+
+        if ($min || $max) {
+            $count = $this->count();
+            if ($min && $count < $min) {
+                throw new \RuntimeException(sprintf('%s relationship has too few objects in it', $this->name));
+            }
+            if ($max && $count > $max) {
+                throw new \RuntimeException(sprintf('%s relationship has too many objects in it', $this->name));
+            }
+        }
+    }
+
+    /**
+     * @param IdentifierInterface $identifier
+     * @return IdentifierInterface
+     */
+    private function checkIdentifier(IdentifierInterface $identifier): IdentifierInterface
+    {
+        if ($this->type !== $identifier->getType()) {
+            throw new \RuntimeException(sprintf('Bad identifier type %s', $identifier->getType()));
+        }
+
+        if (get_class($identifier) !== Identifier::class) {
+            return $identifier;
+        }
+
+        if ($this->type === 'media') {
+            return new MediaIdentifier($identifier->getId());
+        }
+
+        return new FlexIdentifier($identifier->getId(), $identifier->getType());
+    }
+
+    private function parseOptions(array $options): void
+    {
+        $this->type = $options['type'];
+        $this->options = $options;
+    }
+}