Allow to typehint for the type (array/hash) of the root item to be serialized

doc/cookbook/arrays.rst

@@ -0,0 +1,47 @@
+Serailizing arrays and hashes
+=============================
+
+Introduction
+------------
+Serializing arrays and hashes (a concept that in PHP has not explicit boundaries)
+can be challenging. The serializer offers via ``@Type`` annotation different options
+to configure its behavior, but if we try to serialize directly an array
+(not as a property of an object), we need to use context information to determine the
+array "type"
+
+Examples
+--------
+
+In case of a JSON serialization:
+
+.. code-block :: php
+
+    <?php
+
+    // default (let the PHP's json_encode function decide)
+    $serializer->serialize([1, 2]); //  [1, 2]
+    $serializer->serialize(['a', 'b']); //  ['a', 'b']
+    $serializer->serialize(['c' => 'd']); //  {"c" => "d"}
+
+    // same as default (let the PHP's json_encode function decide)
+    $serializer->serialize([1, 2], SerializationContext::create()->setInitialType('array')); //  [1, 2]
+    $serializer->serialize([1 => 2], SerializationContext::create()->setInitialType('array')); //  {"1": 2}
+    $serializer->serialize(['a', 'b'], SerializationContext::create()->setInitialType('array')); //  ['a', 'b']
+    $serializer->serialize(['c' => 'd'], SerializationContext::create()->setInitialType('array')); //  {"c" => "d"}
+
+    // typehint as strict array, keys will be always discarded
+    $serializer->serialize([], SerializationContext::create()->setInitialType('array<integer>')); //  []
+    $serializer->serialize([1, 2], SerializationContext::create()->setInitialType('array<integer>')); //  [1, 2]
+    $serializer->serialize(['a', 'b'], SerializationContext::create()->setInitialType('array<integer>')); //  ['a', 'b']
+    $serializer->serialize(['c' => 'd'], SerializationContext::create()->setInitialType('array<string>')); //  ["d"]
+
+    // typehint as hash, keys will be always considered
+    $serializer->serialize([], SerializationContext::create()->setInitialType('array<integer,integer>')); //  {}
+    $serializer->serialize([1, 2], SerializationContext::create()->setInitialType('array<integer,integer>')); //  {"0" : 1, "1" : 2}
+    $serializer->serialize(['a', 'b'], SerializationContext::create()->setInitialType('array<integer,integer>')); //  {"0" : "a", "1" : "b"}
+    $serializer->serialize(['c' => 'd'], SerializationContext::create()->setInitialType('array<string,string>')); //  {"d" : "d"}
+
+
+.. note ::
+
+    This applies only for the JSON and YAML serialization.

src/JMS/Serializer/GenericSerializationVisitor.php

@@ -91,11 +91,15 @@ public function visitDouble($data, array $type, Context $context)
      */
     public function visitArray($data, array $type, Context $context)
     {
+        $this->dataStack->push($data);
+
+        $isHash = isset($type['params'][1]);
+
         if (null === $this->root) {
-            $this->root = array();
+            $this->root = $isHash ? new \ArrayObject() : array();
             $rs = &$this->root;
         } else {
-            $rs = array();
+            $rs = $isHash ? new \ArrayObject() : array();
         }
 
         $isList = isset($type['params'][0]) && ! isset($type['params'][1]);
@@ -114,6 +118,8 @@ public function visitArray($data, array $type, Context $context)
             }
         }
 
+        $this->dataStack->pop();
+
         return $rs;
     }
 

src/JMS/Serializer/SerializationContext.php

@@ -30,6 +30,11 @@ class SerializationContext extends Context
     /** @var \SplStack */
     private $visitingStack;
 
+    /**
+     * @var string
+     */
+    private $initialType;
+
     public static function create()
     {
         return new self();
@@ -115,4 +120,25 @@ public function getVisitingSet()
     {
         return $this->visitingSet;
     }
+
+    /**
+     * @param string $type
+     * @return $this
+     */
+    public function setInitialType($type)
+    {
+        $this->initialType = $type;
+        $this->attributes->set('initial_type', $type);
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getInitialType()
+    {
+        return $this->initialType
+            ? $this->initialType
+            : $this->attributes->containsKey('initial_type') ? $this->attributes->get('initial_type')->get() : null;
+    }
 }

src/JMS/Serializer/Serializer.php

@@ -107,7 +107,9 @@ public function serialize($data, $format, SerializationContext $context = null)
 
         return $this->serializationVisitors->get($format)
             ->map(function(VisitorInterface $visitor) use ($context, $data, $format) {
-                $this->visit($visitor, $context, $visitor->prepare($data), $format);
+                $type = $context->getInitialType() !== null ? $this->typeParser->parse($context->getInitialType()) : null;
+
+                $this->visit($visitor, $context, $visitor->prepare($data), $format, $type);
 
                 return $visitor->getResult();
             })
@@ -143,7 +145,9 @@ public function toArray($data, SerializationContext $context = null)
 
         return $this->serializationVisitors->get('json')
             ->map(function(JsonSerializationVisitor $visitor) use ($context, $data) {
-                $this->visit($visitor, $context, $data, 'json');
+                $type = $context->getInitialType() !== null ? $this->typeParser->parse($context->getInitialType()) : null;
+
+                $this->visit($visitor, $context, $data, 'json', $type);
                 $result = $this->convertArrayObjects($visitor->getRoot());
 
                 if ( ! is_array($result)) {

src/JMS/Serializer/YamlSerializationVisitor.php

@@ -80,6 +80,8 @@ public function visitString($data, array $type, Context $context)
      */
     public function visitArray($data, array $type, Context $context)
     {
+        $isHash = isset($type['params'][1]);
+
         $count = $this->writer->changeCount;
         $isList = (isset($type['params'][0]) && ! isset($type['params'][1]))
             || array_keys($data) === range(0, count($data) - 1);
@@ -89,7 +91,7 @@ public function visitArray($data, array $type, Context $context)
                 continue;
             }
 
-            if ($isList) {
+            if ($isList && !$isHash) {
                 $this->writer->writeln('-');
             } else {
                 $this->writer->writeln(Inline::dump($k).':');

tests/JMS/Serializer/Tests/Serializer/ContextTest.php

@@ -170,6 +170,18 @@ public function testCanVisitScalars($scalar)
         $context->stopVisiting($scalar);
     }
 
+    public function testInitialTypeCompatibility()
+    {
+        $context = SerializationContext::create();
+        $context->setInitialType('foo');
+        $this->assertEquals('foo', $context->getInitialType());
+        $this->assertEquals('foo', $context->attributes->get('initial_type')->get());
+
+        $context = SerializationContext::create();
+        $context->attributes->set('initial_type', 'foo');
+        $this->assertEquals('foo', $context->getInitialType());
+    }
+
     public function testSerializeNullOption()
     {
         $context = SerializationContext::create();

tests/JMS/Serializer/Tests/Serializer/JsonSerializationTest.php

@@ -26,6 +26,7 @@
 use JMS\Serializer\VisitorInterface;
 use JMS\Serializer\Tests\Fixtures\Author;
 use JMS\Serializer\Tests\Fixtures\AuthorList;
+use JMS\Serializer\SerializationContext;
 
 class JsonSerializationTest extends BaseSerializationTest
 {
@@ -266,6 +267,73 @@ public function testSerializeArrayWithEmptyObject()
         $this->assertEquals('{"0":{}}', $this->serialize(array(new \stdClass())));
     }
 
+    public function testSerializeRootArrayWithDefinedKeys()
+    {
+        $author1 = new Author("Jim");
+        $author2 = new Author("Mark");
+
+        $data = array(
+            'jim' => $author1,
+            'mark' => $author2,
+        );
+
+        $this->assertEquals('{"jim":{"full_name":"Jim"},"mark":{"full_name":"Mark"}}', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array')));
+        $this->assertEquals('[{"full_name":"Jim"},{"full_name":"Mark"}]', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array<JMS\Serializer\Tests\Fixtures\Author>')));
+        $this->assertEquals('{"jim":{"full_name":"Jim"},"mark":{"full_name":"Mark"}}', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array<string,JMS\Serializer\Tests\Fixtures\Author>')));
+
+        $data = array(
+            $author1,
+            $author2,
+        );
+        $this->assertEquals('[{"full_name":"Jim"},{"full_name":"Mark"}]', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array')));
+        $this->assertEquals('{"0":{"full_name":"Jim"},"1":{"full_name":"Mark"}}', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array<int,JMS\Serializer\Tests\Fixtures\Author>')));
+        $this->assertEquals('{"0":{"full_name":"Jim"},"1":{"full_name":"Mark"}}', $this->serializer->serialize($data, $this->getFormat(), SerializationContext::create()->setInitialType('array<string,JMS\Serializer\Tests\Fixtures\Author>')));
+    }
+
+    public function getTypeHintedArrays()
+    {
+        return [
+
+            [[1, 2], '[1,2]', null],
+            [['a', 'b'], '["a","b"]', null],
+            [['a' => 'a', 'b' => 'b'], '{"a":"a","b":"b"}', null],
+
+            [[], '[]', null],
+            [[], '[]', SerializationContext::create()->setInitialType('array')],
+            [[], '[]', SerializationContext::create()->setInitialType('array<integer>')],
+            [[], '{}', SerializationContext::create()->setInitialType('array<string,integer>')],
+
+
+            [[1, 2], '[1,2]', SerializationContext::create()->setInitialType('array')],
+            [[1 => 1, 2 => 2], '{"1":1,"2":2}', SerializationContext::create()->setInitialType('array')],
+            [[1 => 1, 2 => 2], '[1,2]', SerializationContext::create()->setInitialType('array<integer>')],
+            [['a', 'b'], '["a","b"]', SerializationContext::create()->setInitialType('array<string>')],
+
+            [[1 => 'a', 2 => 'b'], '["a","b"]', SerializationContext::create()->setInitialType('array<string>')],
+            [['a' => 'a', 'b' => 'b'], '["a","b"]', SerializationContext::create()->setInitialType('array<string>')],
+
+
+            [[1,2], '{"0":1,"1":2}', SerializationContext::create()->setInitialType('array<integer,integer>')],
+            [[1,2], '{"0":1,"1":2}', SerializationContext::create()->setInitialType('array<string,integer>')],
+            [[1,2], '{"0":"1","1":"2"}', SerializationContext::create()->setInitialType('array<string,string>')],
+
+
+            [['a', 'b'], '{"0":"a","1":"b"}', SerializationContext::create()->setInitialType('array<integer,string>')],
+            [['a' => 'a', 'b' => 'b'], '{"a":"a","b":"b"}', SerializationContext::create()->setInitialType('array<string,string>')],
+        ];
+    }
+
+    /**
+     * @dataProvider getTypeHintedArrays
+     * @param array $array
+     * @param string $expected
+     * @param SerializationContext|null $context
+     */
+    public function testTypeHintedArraySerialization(array $array, $expected, $context = null)
+    {
+        $this->assertEquals($expected, $this->serialize($array, $context));
+    }
+
     protected function getFormat()
     {
         return 'json';

tests/JMS/Serializer/Tests/Serializer/YamlSerializationTest.php

@@ -19,6 +19,7 @@
 namespace JMS\Serializer\Tests\Serializer;
 
 use JMS\Serializer\Exception\RuntimeException;
+use JMS\Serializer\SerializationContext;
 
 class YamlSerializationTest extends BaseSerializationTest
 {
@@ -56,6 +57,51 @@ protected function getContent($key)
         return file_get_contents($file);
     }
 
+    public function getTypeHintedArrays()
+    {
+        return [
+
+            [[1, 2], "- 1\n- 2\n", null],
+            [['a', 'b'], "- a\n- b\n", null],
+            [['a' => 'a', 'b' => 'b'], "a: a\nb: b\n", null],
+
+            [[], " []\n", null],
+            [[], " []\n", SerializationContext::create()->setInitialType('array')],
+            [[], " []\n", SerializationContext::create()->setInitialType('array<integer>')],
+            [[], " {}\n", SerializationContext::create()->setInitialType('array<string,integer>')],
+
+
+            [[1, 2], "- 1\n- 2\n", SerializationContext::create()->setInitialType('array')],
+            [[1 => 1, 2 => 2], "1: 1\n2: 2\n", SerializationContext::create()->setInitialType('array')],
+            [[1 => 1, 2 => 2], "- 1\n- 2\n", SerializationContext::create()->setInitialType('array<integer>')],
+            [['a', 'b'],  "- a\n- b\n", SerializationContext::create()->setInitialType('array<string>')],
+
+            [[1 => 'a', 2 => 'b'],  "- a\n- b\n", SerializationContext::create()->setInitialType('array<string>')],
+            [['a' => 'a', 'b' => 'b'],  "- a\n- b\n", SerializationContext::create()->setInitialType('array<string>')],
+
+
+            [[1,2], "0: 1\n1: 2\n", SerializationContext::create()->setInitialType('array<integer,integer>')],
+            [[1,2], "0: 1\n1: 2\n", SerializationContext::create()->setInitialType('array<string,integer>')],
+            [[1,2], "0: 1\n1: 2\n", SerializationContext::create()->setInitialType('array<string,string>')],
+
+
+            [['a', 'b'], "0: a\n1: b\n", SerializationContext::create()->setInitialType('array<integer,string>')],
+            [['a' => 'a', 'b' => 'b'],  "a: a\nb: b\n", SerializationContext::create()->setInitialType('array<string,string>')],
+        ];
+    }
+
+    /**
+     * @dataProvider getTypeHintedArrays
+     * @param array $array
+     * @param string $expected
+     * @param SerializationContext|null $context
+     */
+    public function testTypeHintedArraySerialization(array $array, $expected, $context = null)
+    {
+        $this->assertEquals($expected, $this->serialize($array, $context));
+    }
+
+
     protected function getFormat()
     {
         return 'yml';