zerver: Accept HEAD requests wherever GET requests are accepted.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

zerver/lib/rest.py

@@ -68,6 +68,9 @@ def rest_dispatch(request: HttpRequest, **kwargs: Any) -> HttpResponse:
             supported_methods[arg] = kwargs[arg]
             del kwargs[arg]
 
+    if 'GET' in supported_methods:
+        supported_methods.setdefault('HEAD', supported_methods['GET'])
+
     if request.method == 'OPTIONS':
         response = HttpResponse(status=204)  # No content
         response['Allow'] = ', '.join(sorted(supported_methods.keys()))

zerver/logging_handlers.py

@@ -61,8 +61,8 @@ def add_request_metadata(report: Dict[str, Any], request: HttpRequest) -> None:
 
     exception_filter = get_exception_reporter_filter(request)
     try:
-        report['data'] = request.GET if request.method == 'GET' else \
-            exception_filter.get_post_parameters(request)
+        report['data'] = exception_filter.get_post_parameters(request) \
+            if request.method == 'POST' else request.GET
     except Exception:
         # exception_filter.get_post_parameters will throw
         # RequestDataTooBig if there's a really big file uploaded

zerver/tests/test_decorators.py

@@ -1709,7 +1709,7 @@ class RestAPITest(ZulipTestCase):
         self.login(self.example_email("hamlet"))
         result = self.client_options('/json/users')
         self.assertEqual(result.status_code, 204)
-        self.assertEqual(str(result['Allow']), 'GET, POST')
+        self.assertEqual(str(result['Allow']), 'GET, HEAD, POST')
 
         result = self.client_options('/json/streams/15')
         self.assertEqual(result.status_code, 204)

zerver/views/auth.py

@@ -11,7 +11,7 @@ from django.http import HttpRequest, HttpResponse, HttpResponseRedirect
 from django.template.response import SimpleTemplateResponse
 from django.shortcuts import redirect, render
 from django.views.decorators.csrf import csrf_exempt
-from django.views.decorators.http import require_GET
+from django.views.decorators.http import require_safe
 from django.utils.translation import ugettext as _
 from django.utils.http import is_safe_url
 from django.core import signing
@@ -555,9 +555,7 @@ def login_page(request: HttpRequest, **kwargs: Any) -> HttpResponse:
     # To support previewing the Zulip login pages, we have a special option
     # that disables the default behavior of redirecting logged-in users to the
     # logged-in app.
-    is_preview = False
-    if request.method == "GET" and request.GET and request.GET.get('preview'):
-        is_preview = True
+    is_preview = 'preview' in request.GET
     if settings.TWO_FACTOR_AUTHENTICATION_ENABLED:
         if request.user and request.user.is_verified():
             return HttpResponseRedirect(request.user.realm.uri)
@@ -565,7 +563,7 @@ def login_page(request: HttpRequest, **kwargs: Any) -> HttpResponse:
         return HttpResponseRedirect(request.user.realm.uri)
     if is_subdomain_root_or_alias(request) and settings.ROOT_DOMAIN_LANDING_PAGE:
         redirect_url = reverse('zerver.views.registration.realm_redirect')
-        if request.method == "GET" and request.GET:
+        if request.GET:
             redirect_url = "{}?{}".format(redirect_url, request.GET.urlencode())
         return HttpResponseRedirect(redirect_url)
 
@@ -790,7 +788,7 @@ def check_server_incompatibility(request: HttpRequest) -> bool:
     user_agent = parse_user_agent(request.META.get("HTTP_USER_AGENT", "Missing User-Agent"))
     return user_agent['name'] == "ZulipInvalid"
 
-@require_GET
+@require_safe
 @csrf_exempt
 def api_get_server_settings(request: HttpRequest) -> HttpResponse:
     # Log which client is making this request.

zerver/views/development/email_log.py

@@ -1,7 +1,7 @@
 from django.conf import settings
 from django.http import HttpRequest, HttpResponse
 from django.shortcuts import render, redirect
-from django.views.decorators.http import require_GET
+from django.views.decorators.http import require_safe
 
 from zerver.models import (
     get_realm, get_user_by_delivery_email, get_realm_stream, Realm,
@@ -43,7 +43,7 @@ def clear_emails(request: HttpRequest) -> HttpResponse:
         pass
     return redirect(email_page)
 
-@require_GET
+@require_safe
 def generate_all_emails(request: HttpRequest) -> HttpResponse:
     if not settings.TEST_SUITE:  # nocoverage
         # It's really convenient to automatically inline the email CSS

zerver/views/realm.py

@@ -3,7 +3,7 @@ from django.http import HttpRequest, HttpResponse
 from django.shortcuts import render
 from django.utils.translation import ugettext as _
 from django.core.exceptions import ValidationError
-from django.views.decorators.http import require_GET
+from django.views.decorators.http import require_safe
 
 from zerver.decorator import require_realm_admin, to_non_negative_int, to_not_negative_int_or_none
 from zerver.lib.actions import (
@@ -204,7 +204,7 @@ def deactivate_realm(request: HttpRequest, user: UserProfile) -> HttpResponse:
     do_deactivate_realm(realm, user)
     return json_success()
 
-@require_GET
+@require_safe
 def check_subdomain_available(request: HttpRequest, subdomain: str) -> HttpResponse:
     try:
         check_subdomain(subdomain)

zerver/webhooks/dropbox/view.py

@@ -7,10 +7,10 @@ from zerver.models import UserProfile
 @api_key_only_webhook_view('Dropbox', notify_bot_owner_on_invalid_json=False)
 @has_request_variables
 def api_dropbox_webhook(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
-    if request.method == 'GET':
-        return HttpResponse(request.GET['challenge'])
-    elif request.method == 'POST':
+    if request.method == 'POST':
         topic = 'Dropbox'
         check_send_webhook_message(request, user_profile, topic,
                                    "File has been updated on Dropbox!")
         return json_success()
+    else:
+        return HttpResponse(request.GET['challenge'])