Implement parsed body methods.

Add more of the PSR7 interface in.

src/Network/Request.php

@@ -1403,6 +1403,36 @@ public function withCookieParams(array $cookies)
         return $new;
     }
 
+    /**
+     * Get the parsed request body data.
+     *
+     * If the request Content-Type is either application/x-www-form-urlencoded
+     * or multipart/form-data, nd the request method is POST, this will be the
+     * post data. For other content types, it may be the deserialized request
+     * body.
+     *
+     * @return null|array|object The deserialized body parameters, if any.
+     *     These will typically be an array or object.
+     */
+    public function getParsedBody()
+    {
+        return $this->data;
+    }
+
+    /**
+     * Update the parsed body and get a new instance.
+     *
+     * @param null|array|object $data The deserialized body data. This will
+     *     typically be in an array or object.
+     * @return static
+     */
+    public function withParsedBody($data)
+    {
+        $new = clone $this;
+        $new->data = $data;
+        return $new;
+    }
+
     /**
      * Get/Set value from the request's environment data.
      * Fallback to using env() if key not set in $environment property.

tests/TestCase/Network/RequestTest.php

@@ -2704,6 +2704,37 @@ public function testWithParam()
         $this->assertSame('Admin', $result->param('prefix'));
     }
 
+    /**
+     * Test getting the parsed body parameters.
+     *
+     * @return void
+     */
+    public function testGetParsedBody()
+    {
+        $data = ['title' => 'First', 'body' => 'Best Article!'];
+        $request = new Request(['post' => $data]);
+        $this->assertSame($data, $request->getParsedBody());
+
+        $request = new Request();
+        $this->assertSame([], $request->getParsedBody());
+    }
+
+    /**
+     * Test replacing the parsed body parameters.
+     *
+     * @return void
+     */
+    public function testWithParsedBody()
+    {
+        $data = ['title' => 'First', 'body' => 'Best Article!'];
+        $request = new Request([]);
+        $new = $request->withParsedBody($data);
+
+        $this->assertNotSame($request, $new);
+        $this->assertSame([], $request->getParsedBody());
+        $this->assertSame($data, $new->getParsedBody());
+    }
+
     /**
      * Test updating POST data in a psr7 fashion.
      *