def to_wire_dict (self):
        """Return a simplified transport object for logging and caching.

        The transport object must contain these attributes:
        - url_data.valid: bool
          Indicates if URL is valid
        - url_data.result: unicode
          Result string
        - url_data.warnings: list of tuples (tag, warning message)
          List of tagged warnings for this URL.
        - url_data.name: unicode string or None
          name of URL (eg. filename or link name)
        - url_data.parent_url: unicode or None
          Parent URL
        - url_data.base_ref: unicode
          HTML base reference URL of parent
        - url_data.url: unicode
          Fully qualified URL.
        - url_data.domain: unicode
          URL domain part.
        - url_data.checktime: int
          Number of seconds needed to check this link, default: zero.
        - url_data.dltime: int
          Number of seconds needed to download URL content, default: -1
        - url_data.size: int
          Size of downloaded URL content, default: -1
        - url_data.info: list of unicode
          Additional information about this URL.
        - url_data.line: int
          Line number of this URL at parent document, or -1
        - url_data.column: int
          Column number of this URL at parent document, or -1
        - url_data.page: int
          Page number of this URL at parent document, or -1
        - url_data.cache_url: unicode
          Cache url for this URL.
        - url_data.content_type: unicode
          MIME content type for URL content.
        - url_data.level: int
          Recursion level until reaching this URL from start URL
        - url_data.last_modified: datetime
          Last modification date of retrieved page (or None).
        """
        return dict(valid=self.valid,
          extern=self.extern[0],
          result=self.result,
          warnings=self.warnings[:],
          name=self.name or u"",
          title=self.get_title(),
          parent_url=self.parent_url or u"",
          base_ref=self.base_ref or u"",
          base_url=self.base_url or u"",
          url=self.url or u"",
          domain=(self.urlparts[1] if self.urlparts else u""),
          checktime=self.checktime,
          dltime=self.dltime,
          size=self.size,
          info=self.info,
          line=self.line,
          column=self.column,
          page=self.page,
          cache_url=self.cache_url,
          content_type=self.content_type,
          level=self.recursion_level,
          modified=self.modified,
        )
Return a simplified transport object for logging and caching.

        The transport object must contain these attributes:
        - url_data.valid: bool
          Indicates if URL is valid
        - url_data.result: unicode
          Result string
        - url_data.warnings: list of tuples (tag, warning message)
          List of tagged warnings for this URL.
        - url_data.name: unicode string or None
          name of URL (eg. filename or link name)
        - url_data.parent_url: unicode or None
          Parent URL
        - url_data.base_ref: unicode
          HTML base reference URL of parent
        - url_data.url: unicode
          Fully qualified URL.
        - url_data.domain: unicode
          URL domain part.
        - url_data.checktime: int
          Number of seconds needed to check this link, default: zero.
        - url_data.dltime: int
          Number of seconds needed to download URL content, default: -1
        - url_data.size: int
          Size of downloaded URL content, default: -1
        - url_data.info: list of unicode
          Additional information about this URL.
        - url_data.line: int
          Line number of this URL at parent document, or -1
        - url_data.column: int
          Column number of this URL at parent document, or -1
        - url_data.page: int
          Page number of this URL at parent document, or -1
        - url_data.cache_url: unicode
          Cache url for this URL.
        - url_data.content_type: unicode
          MIME content type for URL content.
        - url_data.level: int
          Recursion level until reaching this URL from start URL
        - url_data.last_modified: datetime
          Last modification date of retrieved page (or None).