merged branch StanAngeloff/issue-8424-refactoring (PR #8514)

This PR was merged into the master branch.

Discussion
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[Serializer] Added XML attributes support in XmlEncoder

This is a rebase and refactoring of #8424.

---

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8424
| License       | MIT
| Doc PR        | -

---

| New Code | Result
| --- | ---
| Code coverage | 100%
| PSR-2 | No violations
| PHP-CS-Fixer | No changes

---

### TODO

- [ ] **Q**: I looked through `symfony-docs` for any mention of `xml_root_node_name` which is already implemented, but failed to find any. How to best document those new additions?

Commits
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21218cc [Serializer] Added XML attributes support for DomDocument in XmlEncoder.

Author: fabpot

Encoder/XmlEncoder.php

@@ -47,7 +47,7 @@ public function encode($data, $format, array $context = array())
 
         $xmlRootNodeName = $this->resolveXmlRootName($context);
 
-        $this->dom = new \DOMDocument();
+        $this->dom = $this->createDomDocument($context);
         $this->format = $format;
 
         if (null !== $data && !is_scalar($data)) {
@@ -426,4 +426,32 @@ private function resolveXmlRootName(array $context = array())
             : $this->rootNodeName;
     }
 
+    /**
+     * Create a DOM document, taking serializer options into account.
+     *
+     * @param array $context options that the encoder has access to.
+     *
+     * @return \DOMDocument
+     */
+    private function createDomDocument(array $context)
+    {
+        $document = new \DOMDocument();
+
+        // Set an attribute on the DOM document specifying, as part of the XML declaration,
+        $xmlOptions = array(
+            // the version number of the document
+            'xml_version' => 'xmlVersion',
+            // the encoding of the document
+            'xml_encoding' => 'encoding',
+            // whether the document is standalone
+            'xml_standalone' => 'xmlStandalone',
+        );
+        foreach ($xmlOptions as $xmlOption => $documentProperty) {
+            if (isset($context[$xmlOption])) {
+                $document->$documentProperty = $context[$xmlOption];
+            }
+        }
+
+        return $document;
+    }
 }

Tests/Encoder/XmlEncoderTest.php

@@ -118,6 +118,23 @@ public function testEncodeSimpleXML()
         $this->assertEquals($expected, $this->encoder->encode($array, 'xml'));
     }
 
+    public function testEncodeXmlAttributes()
+    {
+        $xml = simplexml_load_string('<firstname>Peter</firstname>');
+        $array = array('person' => $xml);
+
+        $expected = '<?xml version="1.1" encoding="utf-8" standalone="yes"?>'."\n".
+            '<response><person><firstname>Peter</firstname></person></response>'."\n";
+
+        $context = array(
+            'xml_version' => '1.1',
+            'xml_encoding' => 'utf-8',
+            'xml_standalone' => true,
+        );
+
+        $this->assertSame($expected, $this->encoder->encode($array, 'xml', $context));
+    }
+
     public function testEncodeScalarRootAttributes()
     {
         $array = array(