python判斷一個字元是否是xml合法字元

項目中碰到的問題，記錄如下，期望能對他人有用。

def valid_XML_char_ordinal(c):    """    @summary:            check if the char is a valid xml character    @param c: the character to be checked    @see: # http://www.w3.org/TR/2008/REC-xml-20081126/#charsets    @result: True/False    """    return ( # conditions ordered by presumed frequency        0x20 <= c <= 0xD7FF        or c in (0x09, 0x0A, 0x0D)        or 0xE000 <= c <= 0xFFFD        or 0x10000 <= c <= 0x10FFFF        )

考慮對於其他非法xml字元通過base64加密處理，具體代碼如下：

try:    import xml.sax.saxutilsexcept ImportError:    raise ImportError("requires xml.sax.saxutils package, pleas check if xml.sax.saxutils is installed!")import base64import logginglogger = logging.getLogger(__name__)__all__ = ["escape", "unescape"]def escape(data):    """    @summary:            Escape '&', '<', and '>' in a string of data.            if the data is not ascii, then encode in base64    @param data: the data to be processed    @return        {"base64": True | False,         "data": data}    """    # check if all of the data is in ascii code    is_base64 = False    escaped_data = ""    try:        #data.decode("ascii")        if data is None:            data = ""        is_base64 = False        for c in data:            if not valid_XML_char_ordinal(c):                is_base64 = True                break        # check if need base64 encode        if is_base64:            logger.debug("%s is not ascii-encoded string, so i will encode it in base64")            # base64 encode            escaped_data = base64.b64encode(data)        else:            # check if the data should be escaped to be stored in xml            escaped_data = xml.sax.saxutils.escape(data)    except Exception, e:        logger.excpetion(e)    return {"base64": is_base64,            "data": escaped_data}def unescape(data, is_base64 = False):    """    @summary:            Unescape '&amp;', '&lt;', and '&gt;' in a string of data.            if base64 is True, then base64 decode will be processed first    @param data: the data to be processed    @param base64: specify if the data is encoded by base64    @result: unescaped data    """    # check if base64    unescaped_data = data    if is_base64:        try:            unescaped_data = base64.b64decode(data)        except Exception, ex:            logger.debug("some excpetion occured when invoke b64decode")            logger.error(ex)            print ex    else:        # unescape it        unescaped_data = xml.sax.saxutils.unescape(data)    return unescaped_data