IPython/nbformat/current.py

"""The official API for working with notebooks in the current format version."""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

from __future__ import print_function

import re
import warnings

from IPython.nbformat.v3 import (
    NotebookNode,
    new_code_cell, new_text_cell, new_notebook, new_output, new_worksheet,
    parse_filename, new_metadata, new_author, new_heading_cell, nbformat,
    nbformat_minor, nbformat_schema, to_notebook_json,
)
from IPython.nbformat import v3 as _v_latest

from .reader import reads as reader_reads
from .reader import versions
from .convert import convert
from .validator import validate, ValidationError

from IPython.utils.log import get_logger

__all__ = ['NotebookNode', 'new_code_cell', 'new_text_cell', 'new_notebook',
'new_output', 'new_worksheet', 'parse_filename', 'new_metadata', 'new_author',
'new_heading_cell', 'nbformat', 'nbformat_minor', 'nbformat_schema',
'to_notebook_json', 'convert', 'validate', 'NBFormatError', 'parse_py',
'reads_json', 'writes_json', 'reads_py', 'writes_py', 'reads', 'writes', 'read',
'write']

current_nbformat = nbformat
current_nbformat_minor = nbformat_minor
current_nbformat_module = _v_latest.__name__


class NBFormatError(ValueError):
    pass


def _warn_format():
    warnings.warn("""Non-JSON file support in nbformat is deprecated.
    Use nbconvert to create files of other formats.""")


def parse_py(s, **kwargs):
    """Parse a string into a (nbformat, string) tuple."""
    nbf = current_nbformat
    nbm = current_nbformat_minor
    
    pattern = r'# <nbformat>(?P<nbformat>\d+[\.\d+]*)</nbformat>'
    m = re.search(pattern,s)
    if m is not None:
        digits = m.group('nbformat').split('.')
        nbf = int(digits[0])
        if len(digits) > 1:
            nbm = int(digits[1])

    return nbf, nbm, s


def reads_json(nbjson, **kwargs):
    """DEPRECATED, use reads"""
    warnings.warn("reads_json is deprecated, use reads")
    return reads(nbjson)

def writes_json(nb, **kwargs):
    """DEPRECATED, use writes"""
    warnings.warn("writes_json is deprecated, use writes")
    return writes(nb, **kwargs)

def reads_py(s, **kwargs):
    """DEPRECATED: use nbconvert"""
    _warn_format()
    nbf, nbm, s = parse_py(s, **kwargs)
    if nbf in (2, 3):
        nb = versions[nbf].to_notebook_py(s, **kwargs)
    else:
        raise NBFormatError('Unsupported PY nbformat version: %i' % nbf)
    return nb

def writes_py(nb, **kwargs):
    """DEPRECATED: use nbconvert"""
    _warn_format()
    return versions[3].writes_py(nb, **kwargs)


# High level API


def reads(s, format='DEPRECATED', version=current_nbformat, **kwargs):
    """Read a notebook from a string and return the NotebookNode object.

    This function properly handles notebooks of any version. The notebook
    returned will always be in the current version's format.

    Parameters
    ----------
    s : unicode
        The raw unicode string to read the notebook from.

    Returns
    -------
    nb : NotebookNode
        The notebook that was read.
    """
    if format not in {'DEPRECATED', 'json'}:
        _warn_format()
    nb = reader_reads(s, **kwargs)
    nb = convert(nb, version)
    try:
        validate(nb)
    except ValidationError as e:
        get_logger().error("Notebook JSON is invalid: %s", e)
    return nb


def writes(nb, format='DEPRECATED', version=current_nbformat, **kwargs):
    """Write a notebook to a string in a given format in the current nbformat version.

    This function always writes the notebook in the current nbformat version.

    Parameters
    ----------
    nb : NotebookNode
        The notebook to write.
    version : int
        The nbformat version to write.
        Used for downgrading notebooks.

    Returns
    -------
    s : unicode
        The notebook string.
    """
    if format not in {'DEPRECATED', 'json'}:
        _warn_format()
    nb = convert(nb, version)
    try:
        validate(nb)
    except ValidationError as e:
        get_logger().error("Notebook JSON is invalid: %s", e)
    return versions[version].writes_json(nb, **kwargs)


def read(fp, format='DEPRECATED', **kwargs):
    """Read a notebook from a file and return the NotebookNode object.

    This function properly handles notebooks of any version. The notebook
    returned will always be in the current version's format.

    Parameters
    ----------
    fp : file
        Any file-like object with a read method.

    Returns
    -------
    nb : NotebookNode
        The notebook that was read.
    """
    return reads(fp.read(), **kwargs)


def write(nb, fp, format='DEPRECATED', **kwargs):
    """Write a notebook to a file in a given format in the current nbformat version.

    This function always writes the notebook in the current nbformat version.

    Parameters
    ----------
    nb : NotebookNode
        The notebook to write.
    fp : file
        Any file-like object with a write method.
    """
    s = writes(nb, **kwargs)
    if isinstance(s, bytes):
        s = s.decode('utf8')
    return fp.write(s)