Add support for generating QRCodes with 'bridge://' schema for Orbot.

                   "work. On Debian-based systems, this should be in the "

                   "python-qrcode package."))

def generateQR(bridgelines, imageFormat=u'JPEG'):

def generateQR(bridgelines, imageFormat=u'JPEG', bridgeSchema=False):

    """Generate a QRCode for the client's bridge lines.

    :param str bridgelines: The Bridge Lines which we are distributing to the

        client.

    :param bool bridgeSchema: If ``True``, prepend ``'bridge://'`` to the

        beginning of each bridge line before QR encoding.

    :rtype: str or ``None``

    :returns: The generated QRCode, as a string.

    """

    logging.debug("Attempting to encode bridge lines into a QRCode...")

        logging.info("Not creating QRCode for bridgelines; no qrcode module.")

    try:

        if bridgeSchema:

            # See https://bugs.torproject.org/12639 for why bridge:// is used.

            # (Hopefully, Orbot will pick up the ACTION_VIEW intent.)

            schema = 'bridge://'

            prefixed = []

            for line in bridgelines.strip().split('\n'):

                prefixed.append(schema + line)

            bridgelines = '\n'.join(prefixed)

        logging.debug("QR encoding bridge lines: %s" % bridgelines)

        qr = qrcode.QRCode()

        qr.add_data(bridgelines)

        buf = cStringIO.StringIO()

        img = qr.make_image().resize([350, 350])

        img.save(buf, imageFormat)

        buf.seek(0)

        imgstr = buf.read()

        logging.debug("Got QRCode image string.")

        imgstr = buf.read()

        return imgstr

    except KeyError as error:

    except Exception as error:

        logging.error(("There was an error while attempting to generate the "

                       "QRCode: %s") % str(error))