import logging import urllib from typing import Any, Dict, Iterable, List, Optional from urllib.parse import urlencode from django.conf import settings from django.contrib.auth import authenticate, get_backends from django.contrib.sessions.backends.base import SessionBase from django.core import validators from django.core.exceptions import ValidationError from django.db.models import Q from django.http import HttpRequest, HttpResponse, HttpResponseRedirect from django.shortcuts import redirect, render from django.urls import reverse from django.utils.translation import get_language from django_auth_ldap.backend import LDAPBackend, _LDAPUser from confirmation.models import ( Confirmation, ConfirmationKeyException, RealmCreationKey, create_confirmation_link, get_object_from_key, render_confirmation_key_error, validate_key, ) from zerver.actions.create_realm import do_create_realm from zerver.actions.create_user import do_activate_mirror_dummy_user, do_create_user from zerver.actions.default_streams import lookup_default_stream_groups from zerver.actions.user_settings import ( do_change_full_name, do_change_password, do_change_user_setting, ) from zerver.context_processors import get_realm_from_request, login_context from zerver.decorator import do_login, require_post from zerver.forms import ( FindMyTeamForm, HomepageForm, RealmCreationForm, RealmRedirectForm, RegistrationForm, ) from zerver.lib.email_validation import email_allowed_for_realm, validate_email_not_already_in_realm from zerver.lib.exceptions import RateLimited from zerver.lib.i18n import get_default_language_for_new_user from zerver.lib.pysa import mark_sanitized from zerver.lib.rate_limiter import rate_limit_request_by_ip from zerver.lib.request import REQ, has_request_variables from zerver.lib.send_email import EmailNotDeliveredException, FromAddress, send_email from zerver.lib.sessions import get_expirable_session_var from zerver.lib.subdomains import get_subdomain, is_root_domain_available from zerver.lib.url_encoding import append_url_query_string from zerver.lib.users import get_accounts_for_email from zerver.lib.validator import to_converted_or_fallback, to_non_negative_int, to_timezone_or_empty from zerver.lib.zephyr import compute_mit_user_fullname from zerver.models import ( DisposableEmailError, DomainNotAllowedForRealmError, EmailContainsPlusError, MultiuseInvite, PreregistrationUser, Realm, Stream, UserProfile, get_default_stream_groups, get_realm, get_source_profile, get_user_by_delivery_email, name_changes_disabled, ) from zerver.views.auth import ( create_preregistration_user, finish_desktop_flow, finish_mobile_flow, get_safe_redirect_to, redirect_and_log_into_subdomain, redirect_to_deactivation_notice, ) from zproject.backends import ( ExternalAuthResult, ZulipLDAPAuthBackend, ZulipLDAPExceptionNoMatchingLDAPUser, email_auth_enabled, email_belongs_to_ldap, get_external_method_dicts, ldap_auth_enabled, password_auth_enabled, ) if settings.BILLING_ENABLED: from corporate.lib.registration import check_spare_licenses_available_for_registering_new_user from corporate.lib.stripe import LicenseLimitError @has_request_variables def get_prereg_key_and_redirect( request: HttpRequest, confirmation_key: str, full_name: Optional[str] = REQ(default=None) ) -> HttpResponse: """ The purpose of this little endpoint is primarily to take a GET request to a long URL containing a confirmation key, and render a page that will via JavaScript immediately do a POST request to /accounts/register, so that the user can create their account on a page with a cleaner URL (and with the browser security and UX benefits of an HTTP POST having generated the page). The only thing it does before rendering that page is to check the validity of the confirmation link. This is redundant with a similar check in accounts_register, but it provides a slightly nicer user-facing error handling experience if the URL you visited is displayed in the browser. (E.g. you can debug that you accidentally adding an extra character after pasting). """ try: check_prereg_key(request, confirmation_key) except ConfirmationKeyException as e: return render_confirmation_key_error(request, e) return render( request, "confirmation/confirm_preregistrationuser.html", context={"key": confirmation_key, "full_name": full_name}, ) def check_prereg_key(request: HttpRequest, confirmation_key: str) -> PreregistrationUser: """ Checks if the Confirmation key is valid, returning the PreregistrationUser object in case of success and raising an appropriate ConfirmationKeyException otherwise. """ confirmation_types = [ Confirmation.USER_REGISTRATION, Confirmation.INVITATION, Confirmation.REALM_CREATION, ] prereg_user = get_object_from_key(confirmation_key, confirmation_types, mark_object_used=False) assert isinstance(prereg_user, PreregistrationUser) # Defensive assert to make sure no mix-up in how .status is set leading to re-use # of a PreregistrationUser object. assert prereg_user.created_user is None return prereg_user @require_post @has_request_variables def accounts_register( request: HttpRequest, key: str = REQ(default=""), timezone: str = REQ(default="", converter=to_timezone_or_empty), from_confirmation: Optional[str] = REQ(default=None), form_full_name: Optional[str] = REQ("full_name", default=None), source_realm_id: Optional[int] = REQ( default=None, converter=to_converted_or_fallback(to_non_negative_int, None) ), ) -> HttpResponse: try: prereg_user = check_prereg_key(request, key) except ConfirmationKeyException as e: return render_confirmation_key_error(request, e) email = prereg_user.email realm_creation = prereg_user.realm_creation password_required = prereg_user.password_required role = prereg_user.invited_as if realm_creation: role = UserProfile.ROLE_REALM_OWNER try: validators.validate_email(email) except ValidationError: return render(request, "zerver/invalid_email.html", context={"invalid_email": True}) if realm_creation: # For creating a new realm, there is no existing realm or domain realm = None else: assert prereg_user.realm is not None if get_subdomain(request) != prereg_user.realm.string_id: return render_confirmation_key_error( request, ConfirmationKeyException(ConfirmationKeyException.DOES_NOT_EXIST) ) realm = prereg_user.realm try: email_allowed_for_realm(email, realm) except DomainNotAllowedForRealmError: return render( request, "zerver/invalid_email.html", context={"realm_name": realm.name, "closed_domain": True}, ) except DisposableEmailError: return render( request, "zerver/invalid_email.html", context={"realm_name": realm.name, "disposable_emails_not_allowed": True}, ) except EmailContainsPlusError: return render( request, "zerver/invalid_email.html", context={"realm_name": realm.name, "email_contains_plus": True}, ) if realm.deactivated: # The user is trying to register for a deactivated realm. Advise them to # contact support. return redirect_to_deactivation_notice() try: validate_email_not_already_in_realm(realm, email) except ValidationError: return redirect_to_email_login_url(email) if settings.BILLING_ENABLED: try: check_spare_licenses_available_for_registering_new_user(realm, email, role=role) except LicenseLimitError: return render(request, "zerver/no_spare_licenses.html") name_validated = False require_ldap_password = False if from_confirmation: try: del request.session["authenticated_full_name"] except KeyError: pass ldap_full_name = None if settings.POPULATE_PROFILE_VIA_LDAP: # If the user can be found in LDAP, we'll take the full name from the directory, # and further down create a form pre-filled with it. for backend in get_backends(): if isinstance(backend, LDAPBackend): try: ldap_username = backend.django_to_ldap_username(email) except ZulipLDAPExceptionNoMatchingLDAPUser: logging.warning("New account email %s could not be found in LDAP", email) break # Note that this `ldap_user` object is not a # `ZulipLDAPUser` with a `Realm` attached, so # calling `.populate_user()` on it will crash. # This is OK, since we're just accessing this user # to extract its name. # # TODO: We should potentially be accessing this # user to sync its initial avatar and custom # profile fields as well, if we indeed end up # creating a user account through this flow, # rather than waiting until `manage.py # sync_ldap_user_data` runs to populate it. ldap_user = _LDAPUser(backend, ldap_username) try: ldap_full_name = backend.get_mapped_name(ldap_user) except TypeError: break # Check whether this is ZulipLDAPAuthBackend, # which is responsible for authentication and # requires that LDAP accounts enter their LDAP # password to register, or ZulipLDAPUserPopulator, # which just populates UserProfile fields (no auth). require_ldap_password = isinstance(backend, ZulipLDAPAuthBackend) break if ldap_full_name: # We don't use initial= here, because if the form is # complete (that is, no additional fields need to be # filled out by the user) we want the form to validate, # so they can be directly registered without having to # go through this interstitial. form = RegistrationForm({"full_name": ldap_full_name}, realm_creation=realm_creation) request.session["authenticated_full_name"] = ldap_full_name name_validated = True elif realm is not None and realm.is_zephyr_mirror_realm: # For MIT users, we can get an authoritative name from Hesiod. # Technically we should check that this is actually an MIT # realm, but we can cross that bridge if we ever get a non-MIT # zephyr mirroring realm. hesiod_name = compute_mit_user_fullname(email) form = RegistrationForm( initial={"full_name": hesiod_name if "@" not in hesiod_name else ""}, realm_creation=realm_creation, ) name_validated = True elif prereg_user.full_name: if prereg_user.full_name_validated: request.session["authenticated_full_name"] = prereg_user.full_name name_validated = True form = RegistrationForm( {"full_name": prereg_user.full_name}, realm_creation=realm_creation ) else: form = RegistrationForm( initial={"full_name": prereg_user.full_name}, realm_creation=realm_creation ) elif form_full_name is not None: form = RegistrationForm( initial={"full_name": form_full_name}, realm_creation=realm_creation, ) else: form = RegistrationForm(realm_creation=realm_creation) else: postdata = request.POST.copy() if name_changes_disabled(realm): # If we populate profile information via LDAP and we have a # verified name from you on file, use that. Otherwise, fall # back to the full name in the request. try: postdata.update(full_name=request.session["authenticated_full_name"]) name_validated = True except KeyError: pass form = RegistrationForm(postdata, realm_creation=realm_creation) if not (password_auth_enabled(realm) and password_required): form["password"].field.required = False if form.is_valid(): if password_auth_enabled(realm) and form["password"].field.required: password = form.cleaned_data["password"] else: # If the user wasn't prompted for a password when # completing the authentication form (because they're # signing up with SSO and no password is required), set # the password field to `None` (Which causes Django to # create an unusable password). password = None if realm_creation: string_id = form.cleaned_data["realm_subdomain"] realm_name = form.cleaned_data["realm_name"] realm_type = form.cleaned_data["realm_type"] is_demo_org = form.cleaned_data["is_demo_organization"] realm = do_create_realm( string_id, realm_name, org_type=realm_type, is_demo_organization=is_demo_org ) assert realm is not None full_name = form.cleaned_data["full_name"] enable_marketing_emails = form.cleaned_data["enable_marketing_emails"] default_stream_group_names = request.POST.getlist("default_stream_group") default_stream_groups = lookup_default_stream_groups(default_stream_group_names, realm) if source_realm_id is not None: # Non-integer realm_id values like "string" are treated # like the "Do not import" value of "". source_profile: Optional[UserProfile] = get_source_profile(email, source_realm_id) else: source_profile = None if not realm_creation: try: existing_user_profile: Optional[UserProfile] = get_user_by_delivery_email( email, realm ) except UserProfile.DoesNotExist: existing_user_profile = None else: existing_user_profile = None user_profile: Optional[UserProfile] = None return_data: Dict[str, bool] = {} if ldap_auth_enabled(realm): # If the user was authenticated using an external SSO # mechanism like Google or GitHub auth, then authentication # will have already been done before creating the # PreregistrationUser object with password_required=False, and # so we don't need to worry about passwords. # # If instead the realm is using EmailAuthBackend, we will # set their password above. # # But if the realm is using LDAPAuthBackend, we need to verify # their LDAP password (which will, as a side effect, create # the user account) here using authenticate. # prereg_user.realm_creation carries the information about whether # we're in realm creation mode, and the ldap flow will handle # that and create the user with the appropriate parameters. user = authenticate( request=request, username=email, password=password, realm=realm, prereg_user=prereg_user, return_data=return_data, ) if user is None: can_use_different_backend = email_auth_enabled(realm) or ( len(get_external_method_dicts(realm)) > 0 ) if settings.LDAP_APPEND_DOMAIN: # In LDAP_APPEND_DOMAIN configurations, we don't allow making a non-LDAP account # if the email matches the ldap domain. can_use_different_backend = can_use_different_backend and ( not email_belongs_to_ldap(realm, email) ) if return_data.get("no_matching_ldap_user") and can_use_different_backend: # If both the LDAP and Email or Social auth backends are # enabled, and there's no matching user in the LDAP # directory then the intent is to create a user in the # realm with their email outside the LDAP organization # (with e.g. a password stored in the Zulip database, # not LDAP). So we fall through and create the new # account. pass else: # TODO: This probably isn't going to give a # user-friendly error message, but it doesn't # particularly matter, because the registration form # is hidden for most users. view_url = reverse("login") query = urlencode({"email": email}) redirect_url = append_url_query_string(view_url, query) return HttpResponseRedirect(redirect_url) else: assert isinstance(user, UserProfile) user_profile = user if not realm_creation: # Since we'll have created a user, we now just log them in. return login_and_go_to_home(request, user_profile) # With realm_creation=True, we're going to return further down, # after finishing up the creation process. if existing_user_profile is not None and existing_user_profile.is_mirror_dummy: user_profile = existing_user_profile do_activate_mirror_dummy_user(user_profile, acting_user=user_profile) do_change_password(user_profile, password) do_change_full_name(user_profile, full_name, user_profile) do_change_user_setting(user_profile, "timezone", timezone, acting_user=user_profile) do_change_user_setting( user_profile, "default_language", get_default_language_for_new_user(request, realm), acting_user=None, ) # TODO: When we clean up the `do_activate_mirror_dummy_user` code path, # make it respect invited_as_admin / is_realm_admin. if user_profile is None: user_profile = do_create_user( email, password, realm, full_name, prereg_user=prereg_user, role=role, tos_version=settings.TERMS_OF_SERVICE_VERSION, timezone=timezone, default_language=get_default_language_for_new_user(request, realm), default_stream_groups=default_stream_groups, source_profile=source_profile, realm_creation=realm_creation, acting_user=None, enable_marketing_emails=enable_marketing_emails, ) if realm_creation: # Because for realm creation, registration happens on the # root domain, we need to log them into the subdomain for # their new realm. return redirect_and_log_into_subdomain( ExternalAuthResult(user_profile=user_profile, data_dict={"is_realm_creation": True}) ) # This dummy_backend check below confirms the user is # authenticating to the correct subdomain. auth_result = authenticate( username=user_profile.delivery_email, realm=realm, return_data=return_data, use_dummy_backend=True, ) if return_data.get("invalid_subdomain"): # By construction, this should never happen. logging.error( "Subdomain mismatch in registration %s: %s", realm.subdomain, user_profile.delivery_email, ) return redirect("/") assert isinstance(auth_result, UserProfile) return login_and_go_to_home(request, auth_result) return render( request, "zerver/register.html", context={ "form": form, "email": email, "key": key, "full_name": request.session.get("authenticated_full_name", None), "lock_name": name_validated and name_changes_disabled(realm), # password_auth_enabled is normally set via our context processor, # but for the registration form, there is no logged in user yet, so # we have to set it here. "creating_new_team": realm_creation, "password_required": password_auth_enabled(realm) and password_required, "require_ldap_password": require_ldap_password, "password_auth_enabled": password_auth_enabled(realm), "root_domain_available": is_root_domain_available(), "default_stream_groups": [] if realm is None else get_default_stream_groups(realm), "accounts": get_accounts_for_email(email), "MAX_REALM_NAME_LENGTH": str(Realm.MAX_REALM_NAME_LENGTH), "MAX_NAME_LENGTH": str(UserProfile.MAX_NAME_LENGTH), "MAX_PASSWORD_LENGTH": str(form.MAX_PASSWORD_LENGTH), "MAX_REALM_SUBDOMAIN_LENGTH": str(Realm.MAX_REALM_SUBDOMAIN_LENGTH), "corporate_enabled": settings.CORPORATE_ENABLED, "sorted_realm_types": sorted( Realm.ORG_TYPES.values(), key=lambda d: d["display_order"] ), }, ) def login_and_go_to_home(request: HttpRequest, user_profile: UserProfile) -> HttpResponse: mobile_flow_otp = get_expirable_session_var( request.session, "registration_mobile_flow_otp", delete=True ) desktop_flow_otp = get_expirable_session_var( request.session, "registration_desktop_flow_otp", delete=True ) if mobile_flow_otp is not None: return finish_mobile_flow(request, user_profile, mobile_flow_otp) elif desktop_flow_otp is not None: return finish_desktop_flow(request, user_profile, desktop_flow_otp) do_login(request, user_profile) # Using 'mark_sanitized' to work around false positive where Pysa thinks # that 'user_profile' is user-controlled return HttpResponseRedirect(mark_sanitized(user_profile.realm.uri) + reverse("home")) def prepare_activation_url( email: str, session: SessionBase, *, realm: Optional[Realm], realm_creation: bool = False, streams: Optional[Iterable[Stream]] = None, invited_as: Optional[int] = None, multiuse_invite: Optional[MultiuseInvite] = None, ) -> str: """ Send an email with a confirmation link to the provided e-mail so the user can complete their registration. """ prereg_user = create_preregistration_user( email, realm, realm_creation, multiuse_invite=multiuse_invite ) if streams is not None: prereg_user.streams.set(streams) if invited_as is not None: prereg_user.invited_as = invited_as prereg_user.save() confirmation_type = Confirmation.USER_REGISTRATION if realm_creation: confirmation_type = Confirmation.REALM_CREATION activation_url = create_confirmation_link(prereg_user, confirmation_type) if settings.DEVELOPMENT and realm_creation: session["confirmation_key"] = {"confirmation_key": activation_url.split("/")[-1]} return activation_url def send_confirm_registration_email( email: str, activation_url: str, *, realm: Optional[Realm] = None, request: Optional[HttpRequest] = None, ) -> None: send_email( "zerver/emails/confirm_registration", to_emails=[email], from_address=FromAddress.tokenized_no_reply_address(), language=get_language() if request is not None else None, context={ "create_realm": (realm is None), "activate_url": activation_url, }, realm=realm, request=request, ) def redirect_to_email_login_url(email: str) -> HttpResponseRedirect: login_url = reverse("login") redirect_url = append_url_query_string( login_url, urlencode({"email": email, "already_registered": 1}) ) return HttpResponseRedirect(redirect_url) def create_realm(request: HttpRequest, creation_key: Optional[str] = None) -> HttpResponse: try: key_record = validate_key(creation_key) except RealmCreationKey.Invalid: return render( request, "zerver/realm_creation_link_invalid.html", ) if not settings.OPEN_REALM_CREATION: if key_record is None: return render( request, "zerver/realm_creation_disabled.html", ) # When settings.OPEN_REALM_CREATION is enabled, anyone can create a new realm, # with a few restrictions on their email address. if request.method == "POST": form = RealmCreationForm(request.POST) if form.is_valid(): try: rate_limit_request_by_ip(request, domain="sends_email_by_ip") except RateLimited as e: assert e.secs_to_freedom is not None return render( request, "zerver/rate_limit_exceeded.html", context={"retry_after": int(e.secs_to_freedom)}, status=429, ) email = form.cleaned_data["email"] activation_url = prepare_activation_url( email, request.session, realm=None, realm_creation=True ) if key_record is not None and key_record.presume_email_valid: # The user has a token created from the server command line; # skip confirming the email is theirs, taking their word for it. # This is essential on first install if the admin hasn't stopped # to configure outbound email up front, or it isn't working yet. key_record.delete() return HttpResponseRedirect(activation_url) try: send_confirm_registration_email(email, activation_url, request=request) except EmailNotDeliveredException: logging.error("Error in create_realm") return HttpResponseRedirect("/config-error/smtp") if key_record is not None: key_record.delete() return HttpResponseRedirect(reverse("new_realm_send_confirm", kwargs={"email": email})) else: form = RealmCreationForm() return render( request, "zerver/create_realm.html", context={"form": form, "current_url": request.get_full_path}, ) def accounts_home( request: HttpRequest, multiuse_object_key: str = "", multiuse_object: Optional[MultiuseInvite] = None, ) -> HttpResponse: try: realm = get_realm(get_subdomain(request)) except Realm.DoesNotExist: return HttpResponseRedirect(reverse(find_account)) if realm.deactivated: return redirect_to_deactivation_notice() from_multiuse_invite = False streams_to_subscribe = None invited_as = None if multiuse_object: # multiuse_object's realm should have been validated by the caller, # so this code shouldn't be reachable with a multiuse_object which # has its realm mismatching the realm of the request. assert realm == multiuse_object.realm streams_to_subscribe = multiuse_object.streams.all() from_multiuse_invite = True invited_as = multiuse_object.invited_as if request.method == "POST": form = HomepageForm( request.POST, realm=realm, from_multiuse_invite=from_multiuse_invite, invited_as=invited_as, ) if form.is_valid(): try: rate_limit_request_by_ip(request, domain="sends_email_by_ip") except RateLimited as e: assert e.secs_to_freedom is not None return render( request, "zerver/rate_limit_exceeded.html", context={"retry_after": int(e.secs_to_freedom)}, status=429, ) email = form.cleaned_data["email"] try: validate_email_not_already_in_realm(realm, email) except ValidationError: return redirect_to_email_login_url(email) activation_url = prepare_activation_url( email, request.session, realm=realm, streams=streams_to_subscribe, invited_as=invited_as, multiuse_invite=multiuse_object, ) try: send_confirm_registration_email(email, activation_url, request=request, realm=realm) except EmailNotDeliveredException: logging.error("Error in accounts_home") return HttpResponseRedirect("/config-error/smtp") return HttpResponseRedirect(reverse("signup_send_confirm", kwargs={"email": email})) else: form = HomepageForm(realm=realm) context = login_context(request) context.update( form=form, current_url=request.get_full_path, multiuse_object_key=multiuse_object_key, from_multiuse_invite=from_multiuse_invite, ) return render(request, "zerver/accounts_home.html", context=context) def accounts_home_from_multiuse_invite(request: HttpRequest, confirmation_key: str) -> HttpResponse: realm = get_realm_from_request(request) multiuse_object: Optional[MultiuseInvite] = None try: confirmation_obj = get_object_from_key( confirmation_key, [Confirmation.MULTIUSE_INVITE], mark_object_used=False ) assert isinstance(confirmation_obj, MultiuseInvite) multiuse_object = confirmation_obj if realm != multiuse_object.realm: return render(request, "confirmation/link_does_not_exist.html", status=404) # Required for OAuth 2 except ConfirmationKeyException as exception: if realm is None or realm.invite_required: return render_confirmation_key_error(request, exception) return accounts_home( request, multiuse_object_key=confirmation_key, multiuse_object=multiuse_object ) @has_request_variables def find_account( request: HttpRequest, raw_emails: Optional[str] = REQ("emails", default=None) ) -> HttpResponse: url = reverse("find_account") emails: List[str] = [] if request.method == "POST": form = FindMyTeamForm(request.POST) if form.is_valid(): emails = form.cleaned_data["emails"] for i in range(len(emails)): try: rate_limit_request_by_ip(request, domain="sends_email_by_ip") except RateLimited as e: assert e.secs_to_freedom is not None return render( request, "zerver/rate_limit_exceeded.html", context={"retry_after": int(e.secs_to_freedom)}, status=429, ) # Django doesn't support __iexact__in lookup with EmailField, so we have # to use Qs to get around that without needing to do multiple queries. emails_q = Q() for email in emails: emails_q |= Q(delivery_email__iexact=email) user_profiles = UserProfile.objects.filter( emails_q, is_active=True, is_bot=False, realm__deactivated=False ) # We organize the data in preparation for sending exactly # one outgoing email per provided email address, with each # email listing all of the accounts that email address has # with the current Zulip server. context: Dict[str, Dict[str, Any]] = {} for user in user_profiles: key = user.delivery_email.lower() context.setdefault(key, {}) context[key].setdefault("realms", []) context[key]["realms"].append(user.realm) context[key]["external_host"] = settings.EXTERNAL_HOST # This value will end up being the last user ID among # matching accounts; since it's only used for minor # details like language, that arbitrary choice is OK. context[key]["to_user_id"] = user.id for delivery_email, realm_context in context.items(): realm_context["email"] = delivery_email send_email( "zerver/emails/find_team", to_user_ids=[realm_context["to_user_id"]], context=realm_context, from_address=FromAddress.SUPPORT, request=request, ) # Note: Show all the emails in the result otherwise this # feature can be used to ascertain which email addresses # are associated with Zulip. data = urllib.parse.urlencode({"emails": ",".join(emails)}) return redirect(append_url_query_string(url, data)) else: form = FindMyTeamForm() # The below validation is perhaps unnecessary, in that we # shouldn't get able to get here with an invalid email unless # the user hand-edits the URLs. if raw_emails: for email in raw_emails.split(","): try: validators.validate_email(email) emails.append(email) except ValidationError: pass return render( request, "zerver/find_account.html", context={"form": form, "current_url": lambda: url, "emails": emails}, ) @has_request_variables def realm_redirect(request: HttpRequest, next: str = REQ(default="")) -> HttpResponse: if request.method == "POST": form = RealmRedirectForm(request.POST) if form.is_valid(): subdomain = form.cleaned_data["subdomain"] realm = get_realm(subdomain) redirect_to = get_safe_redirect_to(next, realm.uri) return HttpResponseRedirect(redirect_to) else: form = RealmRedirectForm() return render(request, "zerver/realm_redirect.html", context={"form": form})