Expose URI in file fields when serializing an object

1. +++ b/core/modules/hal/lib/Drupal/hal/Normalizer/FileFieldItemNormalizer.php
   @@ -0,0 +1,57 @@
   +  protected $formats = array('json', 'xml');
   

   why is that in hal module and not in the serialization module?

2. +++ b/core/modules/hal/lib/Drupal/hal/Normalizer/FileFieldItemNormalizer.php
   @@ -0,0 +1,57 @@
   +      $values['lang'] = $context['langcode'];
   

   why do you need the language? That is already on the entity object? please add a comment.

But otherwise I think you are on the right track. We need a test case that covers this change.

Since file fields extend entity reference, wouldn't it make sense for this to also support all entity reference items?

Maybe yes, but what about circular references? There have to be some logic to make a "cut"

I don't see how we could have circular references here? we're just calling url(), like hal serialization is too, that could easily live on a more generic normalizer.

Also needs an issue summary update (the examples there are very old) and the issue title should clarify that this is about the json format.

Agree it would make sense to just support all entity reference fields with this. We can rely on ->url() as it comes from EntityInterface, along with every other method under the sun.

This would make it a very similar patch to #2060677: Add target_type, target_uuid to serialized output of entity reference fields in non-HAL formats

File rename not in diff due to pure laziness.

Maybe not assuming there will always be an entity is a good idea.

The EntitySerializationTest should have actually semi-failed already, we just weren't actually using a user in the test, so no 'url' was added from the normalizer.

Here is a modified EntitySerializationTest and a new EntityReferenceFieldItemNormalizerTest unit test.

+1 even using prophecy would be nicer for the tests.

Yeah, prophecy is not a bad idea. None of the other tests use it but hey..

Fixing a the rel param value passed to url() so config entities don't get the edit-form URL put into the normalized data.

Converted to prophecy, that was pretty fun!

Converted to prophecy, that was pretty fun!

Of course it is!

1. +++ b/core/modules/serialization/src/Normalizer/EntityReferenceFieldItemNormalizer.php
   @@ -0,0 +1,39 @@
   +  protected $supportedInterfaceOrClass = 'Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem';
   

   can we use ::class here?

2. +++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
   @@ -0,0 +1,106 @@
   +    $this->fieldItem = $this->prophesize('Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem');
   

   can we use ::class here?

3. +++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
   @@ -0,0 +1,106 @@
   +    $entity = $this->prophesize('Drupal\Core\Entity\EntityInterface');
   

   can we use ::class here?

4. +++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
   @@ -0,0 +1,106 @@
   +    $entity_reference = $this->prophesize('Drupal\Core\TypedData\TypedDataInterface');
   

   and here

5. +++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
   @@ -0,0 +1,106 @@
   +    $entity_reference = $this->prophesize('Drupal\Core\TypedData\TypedDataInterface');
   

   and here

6. +++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
   @@ -0,0 +1,106 @@
   +    $this->fieldItem->get('entity')->willReturn($entity_reference->reveal())->shouldBeCalled();
   

   over 80 characters, can we split this up into multiple lines as we do elsewhere with chained method calls? Also elsewhere.

I can change that, 80 chars is not a limit on lines of code though?

Sure, but if you have 5 "->" operators on one line my head starts spinning.

And yes, you certainly can use it with interface too! :)

+++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityReferenceFieldItemNormalizerTest.php
@@ -69,13 +74,19 @@ public function testSupportsNormalization() {
+    $entity_reference = $this->prophesize(TypedDataInterface::class);
+    $entity_reference->getValue()
+      ->willReturn($entity->reveal())

Meh, actually I think its much more readable if input and output is in one line. At least I don't have to do that in other patches, yeah!

Committed ba447d7 and pushed to 8.0.x. Thanks!

This broke file_entity tests, see #2575741: Priority of serialialization EntityReferenceFieldItemNormalizer must be lower than the one from hal

This was mocked incorrectly. See #2927566: Unit test EntityReferenceFieldItemNormalizerTest mocks incorrectly.