def _assert_valid_url()

in tools/tags_validator.py [0:0]

• 16 lines of code
• 7 McCabe index (conditional complexity)

  def _assert_valid_url(self, possible_url: str) -> None:
    """Checks that the given string is a valid and allowed URL.

    The HTTPS URL should be parseable, not contain spaces and start with an
    allowed prefix.

    Args:
      possible_url: String that should be checked for being an allowed URL.

    Raises:
      TagDefinitionError:
        - if the string is not a valid URL.
        - if the URL contains spaces.
        - if the URL is not an HTTPS URL.
        - if the URL does not specify both a domain and a path.
        - if the URL does not start with one allowed URL prefix.
    """
    try:
      result = urllib.parse.urlparse(possible_url)
    except ValueError:
      raise TagDefinitionError(f"{possible_url} is not a valid URL.")
    if " " in possible_url:
      raise TagDefinitionError(f"{possible_url} must not contain spaces.")
    if result.scheme != HTTPS_SCHEME:
      raise TagDefinitionError(f"{possible_url} is not a HTTPS URL.")
    if not all([result.netloc, result.path]):
      raise TagDefinitionError(
          f"{possible_url} must specify a domain and a path.")
    # Keep the two preceding tests even if the next one is stricter. This should
    # allow to be future proof in case e.g. an http prefix is accidentially
    # added to ALLOWED_URL_PREFIXES.
    if not possible_url.startswith(tuple(ALLOWED_URL_PREFIXES)):
      raise TagDefinitionError(
          f"URL needs to start with any of {sorted(ALLOWED_URL_PREFIXES)}"
          f" but was {possible_url}.")