puppeteer_tests: Use POST for flush_caches call.

tools/test-js-with-puppeteer

@@ -90,7 +90,7 @@ def run_tests(files: Iterable[str], external_host: str) -> None:
             # Resetting test environment.
             reset_zulip_test_database()
             # We are calling to /flush_caches to remove all the server-side caches.
-            response = requests.get("http://zulip.zulipdev.com:9981/flush_caches")
+            response = requests.post("http://zulip.zulipdev.com:9981/flush_caches")
             assert response.status_code == 200
 
             if ret != 0:

zerver/views/development/cache.py

@@ -1,7 +1,9 @@
 import os
 
 from django.http import HttpRequest, HttpResponse
+from django.views.decorators.csrf import csrf_exempt
 
+from zerver.decorator import require_post
 from zerver.lib.cache import get_cache_backend
 from zerver.lib.response import json_success
 from zerver.models import clear_client_cache, flush_per_request_caches
@@ -9,6 +11,8 @@ from zerver.models import clear_client_cache, flush_per_request_caches
 ZULIP_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../../../")
 
 # This is used only by the Puppeteer Tests to clear all the cache after each run.
+@csrf_exempt
+@require_post
 def remove_caches(request: HttpRequest) -> HttpResponse:
     cache = get_cache_backend(None)
     cache.clear()