Class StreamRecoder

Lib/codecs.py:767–882

StreamRecoder instances translate data from one encoding to another. They use the complete set of APIs returned by the codecs.lookup() function to implement their task. Data written to the StreamRecoder is first decoded into an intermediate format (depending on the

###

class StreamRecoder:

    """ StreamRecoder instances translate data from one encoding to another.

        They use the complete set of APIs returned by the
        codecs.lookup() function to implement their task.

        Data written to the StreamRecoder is first decoded into an
        intermediate format (depending on the "decode" codec) and then
        written to the underlying stream using an instance of the provided
        Writer class.

        In the other direction, data is read from the underlying stream using
        a Reader instance and then encoded and returned to the caller.

    """
    # Optional attributes set by the file wrappers below
    data_encoding = 'unknown'
    file_encoding = 'unknown'

    def __init__(self, stream, encode, decode, Reader, Writer,
                 errors='strict'):

        """ Creates a StreamRecoder instance which implements a two-way
            conversion: encode and decode work on the frontend (the
            data visible to .read() and .write()) while Reader and Writer
            work on the backend (the data in stream).

            You can use these objects to do transparent
            transcodings from e.g. latin-1 to utf-8 and back.

            stream must be a file-like object.

            encode and decode must adhere to the Codec interface; Reader and
            Writer must be factory functions or classes providing the
            StreamReader and StreamWriter interfaces resp.

            Error handling is done in the same way as defined for the
            StreamWriter/Readers.

        """
        self.stream = stream
        self.encode = encode
        self.decode = decode
        self.reader = Reader(stream, errors)
        self.writer = Writer(stream, errors)
        self.errors = errors

    def read(self, size=-1):

        data = self.reader.read(size)
        data, bytesencoded = self.encode(data, self.errors)
        return data

    def readline(self, size=None):

        if size is None:
            data = self.reader.readline()