def get_current_url(environ, root_only=False, strip_querystring=False,
                    host_only=False, trusted_hosts=None):
    """A handy helper function that recreates the full URL for the current
    request or parts of it.  Here an example:

    >>> from werkzeug.test import create_environ
    >>> env = create_environ("/?param=foo", "http://localhost/script")
    >>> get_current_url(env)
    'http://localhost/script/?param=foo'
    >>> get_current_url(env, root_only=True)
    'http://localhost/script/'
    >>> get_current_url(env, host_only=True)
    'http://localhost/'
    >>> get_current_url(env, strip_querystring=True)
    'http://localhost/script/'

    This optionally it verifies that the host is in a list of trusted hosts.
    If the host is not in there it will raise a
    :exc:`~werkzeug.exceptions.SecurityError`.

    :param environ: the WSGI environment to get the current URL from.
    :param root_only: set `True` if you only want the root URL.
    :param strip_querystring: set to `True` if you don't want the querystring.
    :param host_only: set to `True` if the host URL should be returned.
    :param trusted_hosts: a list of trusted hosts, see :func:`host_is_trusted`
                          for more information.
    """
    tmp = [environ['wsgi.url_scheme'], '://', get_host(environ, trusted_hosts)]
    cat = tmp.append
    if host_only:
        return uri_to_iri(''.join(tmp) + '/')
    cat(url_quote(wsgi_get_bytes(environ.get('SCRIPT_NAME', ''))).rstrip('/'))
    cat('/')
    if not root_only:
        cat(url_quote(wsgi_get_bytes(environ.get('PATH_INFO', '')).lstrip(b'/')))
        if not strip_querystring:
            qs = get_query_string(environ)
            if qs:
                cat('?' + qs)
    return uri_to_iri(''.join(tmp))
A handy helper function that recreates the full URL for the current
    request or parts of it.  Here an example:

    >>> from werkzeug.test import create_environ
    >>> env = create_environ("/?param=foo", "http://localhost/script")
    >>> get_current_url(env)
    'http://localhost/script/?param=foo'
    >>> get_current_url(env, root_only=True)
    'http://localhost/script/'
    >>> get_current_url(env, host_only=True)
    'http://localhost/'
    >>> get_current_url(env, strip_querystring=True)
    'http://localhost/script/'

    This optionally it verifies that the host is in a list of trusted hosts.
    If the host is not in there it will raise a
    :exc:`~werkzeug.exceptions.SecurityError`.

    :param environ: the WSGI environment to get the current URL from.
    :param root_only: set `True` if you only want the root URL.
    :param strip_querystring: set to `True` if you don't want the querystring.
    :param host_only: set to `True` if the host URL should be returned.
    :param trusted_hosts: a list of trusted hosts, see :func:`host_is_trusted`
                          for more information.