Misago/misago/core/errorpages.py

from django.http import JsonResponse
from django.shortcuts import render
from django.utils.translation import gettext as _
from social_core import exceptions as social_exceptions

from ..admin.views.errorpages import admin_csrf_failure, admin_error_page
from ..socialauth.providers import providers
from .exceptions import SocialAuthBanned, SocialAuthFailed
from .utils import get_exception_message, is_request_to_misago


def _is_ajax(request):
    # Request is AJAX when done with XMLHttpRequest
    if request.headers.get("x-requested-with") == "XMLHttpRequest":
        return True

    # Assume that request is AJAX when it has JSON payload
    return "application/json" in request.headers.get("content-type", "")


def _ajax_error(code, exception=None, default_message=None):
    return JsonResponse(
        {"detail": get_exception_message(exception, default_message)}, status=code
    )


@admin_error_page
def _error_page(request, code, exception=None, default_message=None):
    request.frontend_context.update({"CURRENT_LINK": "misago:error-%s" % code})

    return render(
        request,
        "misago/errorpages/%s.html" % code,
        {"message": get_exception_message(exception, default_message)},
        status=code,
    )


def banned(request, exception):
    ban = exception.ban

    request.frontend_context.update(
        {"MESSAGE": ban.get_serialized_message(), "CURRENT_LINK": "misago:error-banned"}
    )

    return render(request, "misago/errorpages/banned.html", {"ban": ban}, status=403)


def permission_denied(request, exception):
    if _is_ajax(request):
        return _ajax_error(403, exception, _("Permission denied."))
    return _error_page(request, 403, exception)


def page_not_found(request, exception):
    if _is_ajax(request):
        return _ajax_error(404, exception, "Not found.")
    return _error_page(request, 404, exception)


def social_auth_failed(request, exception):
    backend_name = None
    ban = None
    help_text = None
    message = None

    try:
        backend_name = exception.backend_name
    except AttributeError:
        pass

    try:
        exception_backend = exception.backend
        backend_name = providers.get_name(exception_backend.name)
    except AttributeError:
        pass

    if isinstance(exception, social_exceptions.NotAllowedToDisconnect):
        message = _(
            "A problem was encountered when disconnecting your account "
            "from the remote site."
        )
        help_text = _(
            "You are not allowed to disconnect your account from the other site, "
            "because currently it's the only way to sign in to your account."
        )
    elif backend_name:
        message = _(
            "A problem was encountered when signing you in using %(backend)s."
        ) % {"backend": backend_name}

        if isinstance(exception, social_exceptions.AuthCanceled):
            help_text = _("The sign in process has been canceled by user.")
        if isinstance(exception, social_exceptions.AuthUnreachableProvider):
            help_text = _("The other service could not be reached.")
        if isinstance(exception, SocialAuthFailed):
            help_text = exception.message
        if isinstance(exception, SocialAuthBanned):
            ban = exception.ban
    else:
        message = _("Unexpected problem has been encountered during sign in process.")

    return render(
        request,
        "misago/errorpages/social.html",
        {
            "backend_name": backend_name,
            "ban": ban,
            "message": message,
            "help_text": help_text,
        },
        status=403,
    )


@admin_csrf_failure
def csrf_failure(request, reason=""):
    if _is_ajax(request):
        return JsonResponse(
            {
                "detail": _(
                    "Your request was rejected because your browser didn't "
                    "send the CSRF cookie, or the cookie sent was invalid."
                )
            },
            status=403,
        )

    return render(request, "misago/errorpages/csrf_failure.html", status=403)


def not_allowed(request):
    return _error_page(request, 405)


# Decorators for custom error page handlers
def shared_403_exception_handler(f):
    def page_decorator(request, *args, **kwargs):
        if is_request_to_misago(request):
            return permission_denied(request, *args, **kwargs)
        return f(request, *args, **kwargs)

    return page_decorator


def shared_404_exception_handler(f):
    def page_decorator(request, *args, **kwargs):
        if is_request_to_misago(request):
            return page_not_found(request, *args, **kwargs)
        return f(request, *args, **kwargs)

    return page_decorator