NEW Add a trait to dynamically generate edit URLs

code/HasCanonicalEditLink.php

@@ -0,0 +1,146 @@
+<?php
+
+namespace SilverStripe\Admin;
+
+use LogicException;
+use SilverStripe\CMS\Controllers\CMSMain;
+use SilverStripe\Control\Controller;
+use SilverStripe\Control\Director;
+use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\GridField\GridField;
+use SilverStripe\Forms\GridField\GridFieldDetailForm;
+use SilverStripe\ORM\DataObject;
+
+/**
+ * A trait that automatically generates a CMS edit link for DataObjects even if
+ * they are canonically edited in some nested {@link GridField}.
+ * Designed to be used in conjunction with the {@link CMSPreviewable} interface.
+ *
+ * For nested relations (e.g. a DataObject managed in a GridField of another DataObject)
+ * you can apply this trait to both the parent and the child object and the links
+ * will chain down the nested `GridField`s to the root canonical edit owner.
+ *
+ * You must set a canonical_edit_owner config variable which defines the canonical
+ * owner for this class.
+ * e.g. set this to a {@link LeftAndMain} class:
+ * private static string canonical_edit_owner = MyModelAdmin::class;
+ * or to a has_one relation:
+ * private static string canonical_edit_owner = 'Parent';
+ *
+ * Note that the canonical edit owner must implement a getEditLinkForObject() method.
+ *
+ * If the canonical edit owner is a has_one relation, the class on the other end
+ * of the relation must have a CMSEditLink() method.
+ */
+trait HasCanonicalEditLink
+{
+    /**
+     * Get the admin or DataObject which owns this object for CMS editing purposes.
+     *
+     * @return LeftAndMain|DataObject|null
+     */
+    public function getCanonicalEditOwner()
+    {
+        $ownerType = static::config()->get('canonical_edit_owner');
+        if (is_subclass_of($ownerType, LeftAndMain::class)) {
+            return $ownerType::singleton();
+        }
+        return $this->getComponent($ownerType);
+    }
+
+    /**
+     * Get the link for editing an object from the CMS edit form of this object.
+     * @throws LogicException if a link cannot be established
+     * e.g. if the object is not in a has_many relation or not edited inside a GridField.
+     */
+    public function getEditLinkForObject(DataObject $obj, string $reciprocalRelation): string
+    {
+        $fields = $this->getCMSFields();
+        $link = $this->getLinkForRelation($this->hasMany(false), $obj, $reciprocalRelation, $fields);
+        if (!$link) {
+            throw new LogicException('Could not produce an edit link for the passed object.');
+        }
+        return $link;
+    }
+
+    /**
+     * Get a link to edit this page in the CMS.
+     */
+    public function CMSEditLink(): string
+    {
+        $owner = $this->getCanonicalEditOwner();
+        if (!$owner || !$owner->exists()) {
+            return '';
+        }
+
+        if (!$owner->hasMethod('getEditLinkForObject')) {
+            throw new LogicException('The canonical owner must implement getEditLinkForObject()');
+        }
+
+        if ($owner instanceof DataObject) {
+            $relativeLink = $owner->getEditLinkForObject($this, static::config()->get('canonical_edit_owner'));
+        } else {
+            $relativeLink = $owner->getEditLinkForObject($this);
+        }
+        return Director::absoluteURL($relativeLink);
+    }
+
+    private function getLinkForRelation(array $componentConfig, DataObject $obj, string $reciprocalRelation, FieldList $fields): string
+    {
+        $candidate = null;
+        foreach ($componentConfig as $relation => $class) {
+            // Check for dot notation being used to explicitly mark the reciprocal relation.
+            $remoteField = null;
+            if (strpos($class ?? '', '.') !== false) {
+                list($class, $remoteField) = explode('.', $class ?? '');
+            }
+
+            // We're only interested in relations to the $obj class.
+            if (!is_a($obj, $class)) {
+                continue;
+            }
+
+            if ($remoteField) {
+                if ($remoteField === $reciprocalRelation) {
+                    // We've found a direct reciprocal relation, so this is definitely correct.
+                    if ($this->relationIsEditable($relation, $fields)) {
+                        return $this->constructLink($relation, $obj->ID);
+                    }
+                    // If the relation isn't in a gridfield, we have no link for it.
+                    return '';
+                }
+                // We're not interested in unrelated relations.
+                continue;
+            }
+
+            // Check for relations that have gridfields we can build a link from.
+            if ($this->relationIsEditable($relation, $fields)) {
+                $candidate = $relation;
+            }
+        }
+
+        // Only do this if we didn't find a direct reciprocal relation.
+        return $candidate ? $this->constructLink($candidate, $obj->ID) : '';
+    }
+
+    private function relationIsEditable(string $relation, FieldList $fields): bool
+    {
+        $field = $fields->dataFieldByName($relation);
+        return $field
+            && $field instanceof GridField
+            && $field->getConfig()->getComponentByType(GridFieldDetailForm::class);
+    }
+
+    private function constructLink(string $relation, int $id): string
+    {
+        $ownerType = static::config()->get('canonical_edit_owner');
+        $prefix = is_a($ownerType, CMSMain::class, true) ? 'field' : 'ItemEditForm/field';
+        return Controller::join_links(
+            $this->CMSEditLink(),
+            $prefix,
+            $relation,
+            'item',
+            $id
+        );
+    }
+}

tests/php/HasCanonicalEditLinkTest.php

@@ -0,0 +1,98 @@
+<?php
+
+namespace SilverStripe\Admin\Tests;
+
+use LogicException;
+use SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\BasicNestedObject;
+use SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\BelongsToModelAdmin;
+use SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\CanonicalModelAdmin;
+use SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\NestedObject;
+use SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\PolymorphicNestedObject;
+use SilverStripe\Dev\SapphireTest;
+
+class HasCanonicalEditLinkTest extends SapphireTest
+{
+    protected static $fixture_file = 'HasCanonicalEditLinkTest.yml';
+
+    protected $usesDatabase = true;
+
+    protected static $extra_dataobjects = [
+        BelongsToModelAdmin::class,
+        BasicNestedObject::class,
+        NestedObject::class,
+        PolymorphicNestedObject::class,
+    ];
+
+    protected static $extra_controllers = [
+        CanonicalModelAdmin::class,
+    ];
+
+    public function testGetCanonicalEditOwner()
+    {
+        $adminSingleton = CanonicalModelAdmin::singleton();
+        $root = $this->objFromFixture(BelongsToModelAdmin::class, 'root');
+        $basicNested = $this->objFromFixture(BasicNestedObject::class, 'one');
+        $nested = $this->objFromFixture(NestedObject::class, 'one');
+        $polymorphic = $this->objFromFixture(PolymorphicNestedObject::class, 'one');
+
+        $this->assertSame($adminSingleton, $root->getCanonicalEditOwner());
+        $this->assertSame($root->ID, $basicNested->getCanonicalEditOwner()->ID);
+        $this->assertSame($root->ID, $nested->getCanonicalEditOwner()->ID);
+        $this->assertSame($root->ID, $polymorphic->getCanonicalEditOwner()->ID);
+    }
+
+    public function testGetEditLinkForObject()
+    {
+        $root = $this->objFromFixture(BelongsToModelAdmin::class, 'root');
+        $basicNested = $this->objFromFixture(BasicNestedObject::class, 'one');
+        $nested = $this->objFromFixture(NestedObject::class, 'one');
+        $polymorphic = $this->objFromFixture(PolymorphicNestedObject::class, 'one');
+
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/BasicNested/item/$basicNested->ID",
+            $root->getEditLinkForObject($basicNested, 'Parent')
+        );
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/Nested/item/$nested->ID",
+            $root->getEditLinkForObject($nested, 'Parent')
+        );
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/Polymorphic/item/$polymorphic->ID",
+            $root->getEditLinkForObject($polymorphic, 'Parent')
+        );
+    }
+
+    public function testGetEditLinkForObjectException()
+    {
+        $root = $this->objFromFixture(BelongsToModelAdmin::class, 'root');
+        $nested = $this->objFromFixture(NestedObject::class, 'redHerringOne');
+
+        $this->expectException(LogicException::class);
+        $this->assertNull($root->getEditLinkForObject($nested, 'AnotherOfTheSameClass'));
+    }
+
+    public function testCMSEditLink()
+    {
+        $root = $this->objFromFixture(BelongsToModelAdmin::class, 'root');
+        $basicNested = $this->objFromFixture(BasicNestedObject::class, 'one');
+        $nested = $this->objFromFixture(NestedObject::class, 'one');
+        $polymorphic = $this->objFromFixture(PolymorphicNestedObject::class, 'one');
+
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID",
+            $root->CMSEditLink()
+        );
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/BasicNested/item/$basicNested->ID",
+            $basicNested->CMSEditLink()
+        );
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/Nested/item/$nested->ID",
+            $nested->CMSEditLink()
+        );
+        $this->assertSame(
+            "http://localhost/admin/canonical-test/belongsHere/EditForm/field/belongsHere/item/$root->ID/ItemEditForm/field/Polymorphic/item/$polymorphic->ID",
+            $polymorphic->CMSEditLink()
+        );
+    }
+}

tests/php/HasCanonicalEditLinkTest.yml

@@ -0,0 +1,33 @@
+SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\BasicNestedObject:
+  one:
+    Name: 'some name'
+
+SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\PolymorphicNestedObject:
+  one:
+    Name: 'some name'
+
+SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\NestedObject:
+  one:
+    Name: 'some name'
+  redHerringOne:
+    Name: 'This exists so there is a record in an edge-case relation'
+  redHerringTwo:
+    Name: 'This exists so there is a record in an edge-case relation'
+
+SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\BelongsToModelAdmin:
+  redHerringOne:
+    Name: 'This exists so we know it doesnt just grab the first record'
+  root:
+    Name: 'this is the record we care about'
+    Nested:
+      - '=>SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\NestedObject.one'
+    ArbitraryRelation:
+      - '=>SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\NestedObject.redHerringOne'
+    AnotherArbitraryRelation:
+      - '=>SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\NestedObject.redHerringTwo'
+    BasicNested:
+      - '=>SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\BasicNestedObject.one'
+    PolyMorphic:
+      - '=>SilverStripe\Admin\Tests\HasCanonicalEditLinkTest\PolymorphicNestedObject.one'
+  redHerringTwo:
+    Name: 'This exists so we know it doesnt just grab the last record'

tests/php/HasCanonicalEditLinkTest/BasicNestedObject.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\HasCanonicalEditLinkTest;
+
+use SilverStripe\Admin\HasCanonicalEditLink;
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\ORM\DataObject;
+
+class BasicNestedObject extends DataObject implements TestOnly
+{
+    use HasCanonicalEditLink;
+
+    private static $table_name = 'HasCanonicalEditLinkTest_BasicNestedObject';
+
+    private static $canonical_edit_owner = 'Parent';
+
+    private static $db = [
+        'Name' => 'Varchar(25)',
+    ];
+
+    private static $has_one = [
+        'Parent' => BelongsToModelAdmin::class,
+    ];
+}

tests/php/HasCanonicalEditLinkTest/BelongsToModelAdmin.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\HasCanonicalEditLinkTest;
+
+use SilverStripe\Admin\HasCanonicalEditLink;
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\ORM\DataObject;
+
+class BelongsToModelAdmin extends DataObject implements TestOnly
+{
+    use HasCanonicalEditLink;
+
+    private static $table_name = 'HasCanonicalEditLinkTest_BelongsToModelAdmin';
+
+    private static $canonical_edit_owner = CanonicalModelAdmin::class;
+
+    private static $db = [
+        'Name' => 'Varchar(25)',
+    ];
+
+    private static $has_many = [
+        'ArbitraryRelation' => NestedObject::class,
+        'Nested' => NestedObject::class . '.Parent',
+        'AnotherArbitraryRelation' => NestedObject::class . '.AnotherOfTheSameClass',
+        'BasicNested' => BasicNestedObject::class,
+        'PolyMorphic' => PolymorphicNestedObject::class,
+    ];
+
+    public function getCMSFields()
+    {
+        $fields = parent::getCMSFields();
+        $fields->removeByName(['ArbitraryRelation', 'AnotherArbitraryRelation']);
+        return $fields;
+    }
+}

tests/php/HasCanonicalEditLinkTest/CanonicalModelAdmin.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\HasCanonicalEditLinkTest;
+
+use SilverStripe\Admin\ModelAdmin;
+use SilverStripe\Dev\TestOnly;
+
+class CanonicalModelAdmin extends ModelAdmin implements TestOnly
+{
+    private static $url_segment = 'canonical-test';
+
+    private static $managed_models = [
+        'belongsHere' => BelongsToModelAdmin::class,
+    ];
+}

tests/php/HasCanonicalEditLinkTest/NestedObject.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\HasCanonicalEditLinkTest;
+
+use SilverStripe\Admin\HasCanonicalEditLink;
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\ORM\DataObject;
+
+class NestedObject extends DataObject implements TestOnly
+{
+    use HasCanonicalEditLink;
+
+    private static $table_name = 'HasCanonicalEditLinkTest_NestedObject';
+
+    private static $canonical_edit_owner = 'Parent';
+
+    private static $db = [
+        'Name' => 'Varchar(25)',
+    ];
+
+    private static $has_one = [
+        'Parent' => BelongsToModelAdmin::class,
+        'AnotherOfTheSameClass' => BelongsToModelAdmin::class,
+        'ThirdOne' => BelongsToModelAdmin::class,
+    ];
+}