changed default cache behavior

flight/net/Response.php

@@ -288,13 +288,7 @@ class Response
     {
         if ($expires === false) {
             $this->headers['Expires'] = 'Mon, 26 Jul 1997 05:00:00 GMT';
-
+            $this->headers['Cache-Control'] = 'no-store, no-cache, must-revalidate';
-            $this->headers['Cache-Control'] = [
-                'no-store, no-cache, must-revalidate',
-                'post-check=0, pre-check=0',
-                'max-age=0',
-            ];
-
             $this->headers['Pragma'] = 'no-cache';
         } else {
             $expires = \is_int($expires) ? $expires : strtotime($expires);
@@ -437,8 +431,14 @@ class Response
             $this->processResponseCallbacks();
         }
 
-        if (headers_sent() === false) {
+        if ($this->headersSent() === false) {
-            $this->sendHeaders(); // @codeCoverageIgnore
+
+			// If you haven't set a Cache-Control header, we'll assume you don't want caching
+			if($this->getHeader('Cache-Control') === null) {
+				$this->cache(false);
+			}
+
+            $this->sendHeaders();
         }
 
         echo $this->body;
@@ -446,6 +446,17 @@ class Response
         $this->sent = true;
     }
 
+	/**
+	 * Headers have been sent
+	 * 
+	 * @return bool
+	 * @codeCoverageIgnore
+	 */
+	public function headersSent(): bool
+	{
+		return headers_sent();
+	}
+
     /**
      * Adds a callback to process the response body before it's sent. These are processed in the order
      * they are added

tests/ResponseTest.php

@@ -164,11 +164,7 @@ class ResponseTest extends TestCase
         $response->cache(false);
         $this->assertEquals([
             'Expires' => 'Mon, 26 Jul 1997 05:00:00 GMT',
-            'Cache-Control' => [
+            'Cache-Control' => 'no-store, no-cache, must-revalidate',
-                'no-store, no-cache, must-revalidate',
-                'post-check=0, pre-check=0',
-                'max-age=0',
-            ],
             'Pragma' => 'no-cache'
         ], $response->headers());
     }
@@ -239,6 +235,46 @@ class ResponseTest extends TestCase
         $this->assertTrue($response->sent());
     }
 
+	public function testSendWithNoHeadersSent()
+	{
+        $response = new class extends Response {
+            protected $test_sent_headers = [];
+
+            public function setRealHeader(string $header_string, bool $replace = true, int $response_code = 0): self
+            {
+                $this->test_sent_headers[] = $header_string;
+                return $this;
+            }
+
+            public function getSentHeaders(): array
+            {
+                return $this->test_sent_headers;
+            }
+
+			public function headersSent(): bool
+			{
+				return false;
+			}
+        };
+        $response->header('Content-Type', 'text/html');
+        $response->header('X-Test', 'test');
+        $response->write('Something');
+
+		$this->expectOutputString('Something');
+
+        $response->send();
+        $sent_headers = $response->getSentHeaders();
+        $this->assertEquals([
+            'HTTP/1.1 200 OK',
+            'Content-Type: text/html',
+            'X-Test: test',
+			'Expires: Mon, 26 Jul 1997 05:00:00 GMT',
+            'Cache-Control: no-store, no-cache, must-revalidate',
+			'Pragma: no-cache',
+            'Content-Length: 9'
+        ], $sent_headers);
+    }
+
     public function testClearBody()
     {
         $response = new Response();