fix(middleware): log responses that are not JSON

docs/redaction.md

@@ -22,3 +22,6 @@ file](configuration.md) and adjust the `redact` options in `config/api-logs.php`
 
 `keys` are matched case-insensitively and recursively against the request payload,
 query string and response data; `headers` are matched against request header names.
+
+Key redaction applies to JSON responses only. A response that is not JSON, such as an
+HTML error page, is stored as its raw body, unredacted.

src/Http/Middleware/LogApiRequest.php

@@ -35,9 +35,6 @@ public function terminate(Request $request, Response $response): void
             ?? $request->server('REQUEST_TIME_FLOAT')
             ?? microtime(true);
 
-        $content = $response->getContent();
-        $responseData = is_string($content) ? json_decode($content, true) : null;
-
         $keys = config('api-logs.redact.keys', []);
         $headers = config('api-logs.redact.headers', []);
         $replacement = config('api-logs.redact.replacement', '[REDACTED]');
@@ -51,7 +48,28 @@ public function terminate(Request $request, Response $response): void
             'ip' => $request->getClientIp(),
             'request_data' => Redactor::redact($request->all(), $keys, $replacement),
             'request_headers' => Redactor::redactHeaders($request->headers->all(), $headers, $replacement),
-            'response_data' => is_array($responseData) ? Redactor::redact($responseData, $keys, $replacement) : $responseData,
+            'response_data' => $this->responseData($response, $keys, $replacement),
         ]);
     }
+
+    /**
+     * Get the response body to store: the decoded JSON value when the body
+     * is JSON, or the raw body as a UTF-8 string otherwise.
+     */
+    private function responseData(Response $response, array $keys, string $replacement): mixed
+    {
+        $content = $response->getContent();
+
+        if (! is_string($content)) {
+            return '';
+        }
+
+        $decoded = json_decode($content, true);
+
+        if (is_array($decoded)) {
+            return Redactor::redact($decoded, $keys, $replacement);
+        }
+
+        return $decoded ?? mb_scrub($content, 'UTF-8');
+    }
 }

tests/Feature/LogApiRequestMiddlewareTest.php

@@ -18,6 +18,10 @@ protected function defineRoutes($router): void
                 'user' => ['email' => 'user@example.com'],
                 'access_token' => 'issued-token',
             ]));
+            $router->get('/api/forbidden', fn () => abort(403));
+            $router->delete('/api/items', fn () => response()->noContent());
+            $router->get('/api/export', fn () => response()->stream(fn () => print 'a,b,c'));
+            $router->get('/api/binary', fn () => response("abc\xff"));
         });
     }
 
@@ -136,6 +140,54 @@ public function test_request_is_not_logged_when_configured_guard_is_unauthentica
         $this->assertSame(0, ApiLog::count());
     }
 
+    public function test_html_response_is_logged_with_its_raw_body(): void
+    {
+        $this->actingAs($this->createUser())
+            ->get('/api/forbidden', ['Accept' => '*/*'])
+            ->assertForbidden();
+
+        $log = ApiLog::first();
+
+        $this->assertIsString($log->response_data);
+        $this->assertStringContainsString('<html', $log->response_data);
+    }
+
+    public function test_empty_response_is_logged_with_an_empty_body(): void
+    {
+        $this->actingAs($this->createUser())
+            ->delete('/api/items')
+            ->assertNoContent();
+
+        $this->assertSame('', ApiLog::first()->response_data);
+    }
+
+    public function test_streamed_response_is_logged_with_an_empty_body(): void
+    {
+        $this->actingAs($this->createUser())
+            ->get('/api/export')
+            ->assertOk();
+
+        $this->assertSame('', ApiLog::first()->response_data);
+    }
+
+    public function test_response_that_is_not_valid_utf8_is_logged_with_its_body_scrubbed(): void
+    {
+        $this->actingAs($this->createUser())
+            ->get('/api/binary')
+            ->assertOk();
+
+        $this->assertSame('abc?', ApiLog::first()->response_data);
+    }
+
+    private function createUser(): User
+    {
+        return User::create([
+            'name' => 'Test User',
+            'email' => 'user@example.com',
+            'password' => 'secret',
+        ]);
+    }
+
     private function defineApiGuard(): void
     {
         config()->set('auth.guards.api', ['driver' => 'session', 'provider' => 'users']);