Fix json deserialization error (#320)

* Fix JSON deserialization error in SmartSerializer

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

* test: modify assert

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

* Fix checking for json content type when decoding

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

* Add a test for missing Content-Type header

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

* Fixed header case normalization and content type checks

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

---------

Signed-off-by: takuyanakazawa <t.nakazawa0222@gmail.com>

Author: tn2222

CHANGELOG.md

@@ -11,6 +11,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Deprecated
 ### Removed
 ### Fixed
+- Fixed checking for content type in JSON deserialization ([#318](https://github.com/opensearch-project/opensearch-php/issues/318))
 - Fixed mismatch in return types between `Client::performRequest()` and `Transport::sendRequest()` ([#307](https://github.com/opensearch-project/opensearch-php/issues/307))
 - Fixed legacy client options being passed as headers ([#301](https://github.com/opensearch-project/opensearch-php/issues/301))
 - Fixed endpoint options not being passed to legacy transport ([#296](https://github.com/opensearch-project/opensearch-php/issues/296))

src/OpenSearch/Serializers/SmartSerializer.php

@@ -56,17 +56,10 @@ public function serialize($data): string
      */
     public function deserialize(?string $data, array $headers)
     {
-        if (isset($headers['content_type']) === true) {
-            if (strpos($headers['content_type'], 'json') !== false) {
-                return $this->decode($data);
-            } else {
-                //Not json, return as string
-                return $data;
-            }
-        } else {
-            //No content headers, assume json
+        if ($this->isJson($headers)) {
             return $this->decode($data);
         }
+        return $data;
     }
 
     /**
@@ -86,4 +79,31 @@ private function decode(?string $data): array
             throw new JsonException($e->getCode(), $data, $e);
         }
     }
+
+    /**
+     * Check the response content type to see if it is JSON.
+     *
+     * @param array<string,mixed> $headers
+     */
+    private function isJson(array $headers): bool
+    {
+        // Legacy support for 'transfer_stats'.
+        if (array_key_exists('content_type', $headers)) {
+            return str_contains($headers['content_type'], 'json');
+        }
+
+        // Check PSR-7 headers.
+        $lowercaseHeaders = array_change_key_case($headers, CASE_LOWER);
+        if (array_key_exists('content-type', $lowercaseHeaders)) {
+            foreach ($lowercaseHeaders['content-type'] as $type) {
+                if (str_contains($type, 'json')) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        // No content type header, so assume it is JSON.
+        return true;
+    }
 }

tests/Serializers/SmartSerializerTest.php

@@ -58,4 +58,53 @@ public function testThrowJsonException(): void
         }
     }
 
+    public function testDeserialize(): void
+    {
+        $data = '{ "foo" : "bar" }';
+        $headers = ['Content-Type' => ['application/json']];
+
+        $result = $this->serializer->deserialize($data, $headers);
+
+        $this->assertEquals('bar', $result['foo']);
+    }
+
+    public function testDeserializeLowercaseContentTypeHeader(): void
+    {
+        $data = '{ "foo" : "bar" }';
+        $headers = ['content-type' => ['application/json']];
+
+        $result = $this->serializer->deserialize($data, $headers);
+
+        $this->assertEquals('bar', $result['foo']);
+    }
+
+    public function testDeserializeWithLegacyContentTypeHeader(): void
+    {
+        $data = '{ "foo" : "bar" }';
+        $headers = ['content_type' => 'application/json'];
+
+        $result = $this->serializer->deserialize($data, $headers);
+
+        $this->assertEquals('bar', $result['foo']);
+    }
+
+    public function testDeserializeNonJsonData(): void
+    {
+        $data = 'plain text data';
+        $headers = ['Content-Type' => ['text/plain']];
+
+        $result = $this->serializer->deserialize($data, $headers);
+
+        $this->assertEquals('plain text data', $result);
+    }
+
+    public function testDeserializeWithNoContentTypeHeader(): void
+    {
+        $data = '{ "foo" : "bar" }';
+        $headers = [];
+
+        $result = $this->serializer->deserialize($data, $headers);
+
+        $this->assertEquals('bar', $result['foo']);
+    }
 }