peek([size]) Return bytes from the stream without advancing the position. At most one single read on the raw stream is done to satisfy the call. The number of bytes returned may be less or more than requested.

class io.BufferedReader(raw, buffer_size=DEFAULT_BUFFER_SIZE) A buffer providing higher-level access to a readable, sequential RawIOBase object. It inherits BufferedIOBase. When reading data from this object, a larger amount of data may be requested from the underlying raw stream, and kept in an internal buffer. The buffered data can then be returned directly on subsequent reads. The constructor creates a BufferedReader for the given readable raw stream and buffer_size. If buffer_size is omi

class io.BufferedRandom(raw, buffer_size=DEFAULT_BUFFER_SIZE) A buffered interface to random access streams. It inherits BufferedReader and BufferedWriter, and further supports seek() and tell() functionality. The constructor creates a reader and writer for a seekable raw stream, given in the first argument. If the buffer_size is omitted it defaults to DEFAULT_BUFFER_SIZE. BufferedRandom is capable of anything BufferedReader or BufferedWriter can do.

write(b) Write the given bytes-like object, b, and return the number of bytes written (always equal to the length of b in bytes, since if the write fails an OSError will be raised). Depending on the actual implementation, these bytes may be readily written to the underlying stream, or held in a buffer for performance and latency reasons. When in non-blocking mode, a BlockingIOError is raised if the data needed to be written to the raw stream but it couldn’t accept all the data without blocki

readinto1(b) Read bytes into a pre-allocated, writable bytes-like object b, using at most one call to the underlying raw stream’s read() (or readinto()) method. Return the number of bytes read. A BlockingIOError is raised if the underlying raw stream is in non blocking-mode, and has no data available at the moment. New in version 3.5.

readinto(b) Read bytes into a pre-allocated, writable bytes-like object b and return the number of bytes read. Like read(), multiple reads may be issued to the underlying raw stream, unless the latter is interactive. A BlockingIOError is raised if the underlying raw stream is in non blocking-mode, and has no data available at the moment.

read1(size=-1) Read and return up to size bytes, with at most one call to the underlying raw stream’s read() (or readinto()) method. This can be useful if you are implementing your own buffering on top of a BufferedIOBase object.

read(size=-1) Read and return up to size bytes. If the argument is omitted, None, or negative, data is read and returned until EOF is reached. An empty bytes object is returned if the stream is already at EOF. If the argument is positive, and the underlying raw stream is not interactive, multiple raw reads may be issued to satisfy the byte count (unless EOF is reached first). But for interactive raw streams, at most one raw read will be issued, and a short result does not imply that EOF is i

raw The underlying raw stream (a RawIOBase instance) that BufferedIOBase deals with. This is not part of the BufferedIOBase API and may not exist on some implementations.

detach() Separate the underlying raw stream from the buffer and return it. After the raw stream has been detached, the buffer is in an unusable state. Some buffers, like BytesIO, do not have the concept of a single raw stream to return from this method. They raise UnsupportedOperation. New in version 3.1.