fix: Ignore non-HTML responses in storePreviousURL

system/CodeIgniter.php

@@ -1031,6 +1031,11 @@ public function storePreviousURL($uri)
  return;
  }
 
+ // Ignore non-HTML responses
+ if (strpos($this->response->getHeaderLine('Content-Type'), 'text/html') === false) {
+ return;
+ }
+
  // This is mainly needed during testing...
  if (is_string($uri)) {
  $uri = new URI($uri);

tests/system/CodeIgniterTest.php

@@ -424,6 +424,30 @@ public function testNotStoresPreviousURL()
  $this->assertArrayNotHasKey('_ci_previous_url', $_SESSION);
  }
 
+ public function testNotStoresPreviousURLByCheckingContentType()
+ {
+ $_SERVER['argv'] = ['index.php', 'image'];
+ $_SERVER['argc'] = 2;
+
+ $_SERVER['REQUEST_URI'] = '/image';
+
+ // Inject mock router.
+ $routes = Services::routes();
+ $routes->add('image', static function () {
+ $response = Services::response();
+
+ return $response->setContentType('image/jpeg', '');
+ });
+ $router = Services::router($routes, Services::request());
+ Services::injectMock('router', $router);
+
+ ob_start();
+ $this->codeigniter->useSafeOutput(true)->run();
+ ob_get_clean();
+
+ $this->assertArrayNotHasKey('_ci_previous_url', $_SESSION);
+ }
+
  /**
  * The method after all test, reset Servces:: config
  * Can't use static::tearDownAfterClass. This will cause a buffer exception

user_guide_src/source/changelogs/v4.2.0.rst

@@ -32,6 +32,7 @@ Behavior Changes
 - To prevent unexpected access from the web browser, if a controller is added to a cli route (``$routes->cli()``), all methods of that controller are no longer accessible via auto-routing.
 - There is a possible backward compatibility break for those users extending the History Collector and they should probably update ``History::setFiles()`` method.
 - The :php:func:`dot_array_search`'s unexpected behavior has been fixed. Now ``dot_array_search('foo.bar.baz', ['foo' => ['bar' => 23]])`` returns ``null``. The previous versions returned ``23``.
+- The ``CodeIgniter::storePreviousURL()`` has been changed to store only the URLs whose Content-Type was ``text/html``. It also affects the behavior of :php:func:`previous_url` and :php:func:`redirect()->back() <redirect>`.
 
 Enhancements
 ************