Source code for concurrency.views

from typing import NoReturn

from django.http import HttpResponse
from django.template import loader, TemplateDoesNotExist
from django.template.base import Template
from django.utils.translation import gettext as _

from concurrency.exceptions import RecordModifiedError


class ConflictResponse(HttpResponse):
    status_code = 409


def callback(target, *args, **kwargs) -> NoReturn:
    raise RecordModifiedError(_("Record has been modified"), target=target)




def conflict(request, target=None, template_name="409.html"):
    """409 error handler.

    :param request: Request

    :param template_name: `409.html`

    :param target: The model to save

    """
    try:
        template = loader.get_template(template_name)
    except TemplateDoesNotExist:  # pragma: no cover
        template = Template(
            "<h1>Conflict</h1>"
            "<p>The request was unsuccessful due to a conflict. "
            "The object changed during the transaction.</p>"
        )
    try:
        saved = target.__class__._default_manager.get(pk=target.pk)
    except target.__class__.DoesNotExist:  # pragma: no cover
        saved = None
    ctx = {"target": target, "saved": saved, "request_path": request.path}

    return ConflictResponse(template.render(ctx))