Add serializer support for XML

Here is an initial patch for this. I think the idea is right and this would work except adding the serializer as an argument in the container doesn't work atm (it might, I'm just not sure how to get it to). There is a circular dep issue as there are various passes to add normalizers/encoders to the serializer too.

I think this might be better.

Don't need the use statement for SerializerInterface

Example XML string, as returned by the test:

<?xml version="1.0"?>
<response>
  <id>
    <value>1</value>
  </id>
  <revision_id>
    <value>1</value>
  </revision_id>
  <uuid>
    <value>c84e1b09-da08-4f96-9403-3b965ccdd6c9</value>
  </uuid>
  <langcode>
    <value>und</value>
  </langcode>
  <default_langcode>
    <value/>
  </default_langcode>
  <name>
    <value>nGCbib3H</value>
  </name>
  <user_id>
    <value>1</value>
  </user_id>
  <field_test_text>
    <value>bUWBFGXZ</value>
    <format>full_html</format>
  </field_test_text>
</response>

Just updated the docs a little.

#6: 1854874-4.patch queued for re-testing.

Come on!

#6: 1854874-4.patch queued for re-testing.

Ok, I changed the $format to be an array, this is then consistent with all our other encoders. Which I think makes sense, even though there is only one format.

Injecting this sounds like a good idea, but would we ever need this? We could change the name to EncoderWrapper or something? Then pass in the XmlEncoder as the base encoder?

I'm not sure what else to test, because this is not about the normalizers. The serlizer deals with that.

How about we test serializing the normalized array as well as the entity like this?

We talked about this on IRC briefly; How about this?

Ok, let's get rid of that and so our string is the expected.

Oh dear... :( Good catch Alex. I guess this shows that it was a bit fragile to have the whole string in the test? And these changes DO make it easier to modify down the line. Maybe we can make it easier:

+++ b/core/modules/system/lib/Drupal/system/Tests/Serialization/EntitySerializationTest.phpundefined
@@ -130,12 +129,33 @@
+    $expected = array_merge(array_flip(array_keys($normalized)), $expected);

I can see how it is quite confusing, but I quite like this. If we want something more readable, I guess we can just use a foreach here and iterate over the array_keys OR we could just use array_merge (and drop the other two array methods) really, as the normalized values will get overwritten by the expected array values anyway, so we don't need an array of empty values.

+++ b/core/modules/system/lib/Drupal/system/Tests/Serialization/EntitySerializationTest.phpundefined
@@ -130,12 +129,33 @@
+    $expected = array_reduce($expected, function($result, $item) {
+      $result .= $item;
+      return $result;
+    });

I think just implode('', $expected) would be fine here? array_reduce seems OTT here when it's just concatenating strings.

+++ b/core/modules/system/lib/Drupal/system/Tests/Serialization/EntitySerializationTest.phpundefined
@@ -130,12 +129,33 @@
+    $this->assertIdentical($actual, $expected);
...
+    $this->assertIdentical($actual, $expected);

the assertion message haz gone :)

Alex I will let you action this, if you don't have time, let me know and I will re roll.

Hmm, When the Symfony XmlEncoder decodes the xml it won't match the the original normalized data array, as it seems to remove a level of empty arrays (I think). So we could check the keys, but that's not ideal?

Ok, here is a new version of the patch from #26, but with some parts simplified. I'm not sure the de-serialization method will work, so for now, this is the way to go I think.

For example:

'id' => array(
  array('value' => 1),
)

would become...

'id' => array(
  'value' => 1,
)

#33: 1854874-33.patch queued for re-testing.