Header Content-type from request in ApiProxyTrait

src/Controller/ApiProxyTrait.php

@@ -40,6 +40,13 @@ trait ApiProxyTrait
 {
     use ViewVarsTrait;
 
+    /**
+     * Default allowed headers on proxied requests.
+     *
+     * @var array
+     */
+    protected $allowedHeaders = ['Content-Type'];
+
     /**
      * An instance of a \Cake\Http\ServerRequest object that contains information about the current request.
      *
@@ -182,6 +189,13 @@ protected function apiRequest(array $options): void
             'body' => null,
             'headers' => null,
         ];
+        foreach ($this->allowedHeaders as $headerName) {
+            if (empty($this->request->getHeader($headerName))) {
+                continue;
+            }
+            $options['headers'] = $options['headers'] ?? [];
+            $options['headers'][$headerName] = $this->request->getHeader($headerName);
+        }
 
         if (empty($options['body'])) {
             $options['body'] = null;

tests/TestCase/Controller/ApiProxyTraitTest.php

@@ -122,6 +122,19 @@ public function testGet(): void
         }
     }
 
+    /**
+     * Test get() method
+     *
+     * @return void
+     * @covers ::apiRequest()
+     */
+    public function testGetWithHeaders(): void
+    {
+        $this->_request['headers'] = ['Content-type' => 'text/plain'];
+        $this->get('/api/users/1');
+        $this->assertResponseOk();
+    }
+
     /**
      * Test non found error proxied from API.
      *