Make nbformat.(read|write) accept file-like object or path

IPython/nbformat/__init__.py

@@ -5,6 +5,8 b' Use this module to read or write notebook files as particular nbformat versions.'
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+import io
+from IPython.utils import py3compat
 
 from IPython.utils.log import get_logger
 
@@ -112,8 +114,8 b' def read(fp, as_version, **kwargs):'
 
     Parameters
     ----------
-    fp : file
-        Any file-like object with a read method.
+    fp : file or str
+        Any file-like object with a read method, or a path to a file.
     as_version: int
         The version of the notebook format to return.
         The notebook will be converted, if necessary.
@@ -124,6 +126,10 b' def read(fp, as_version, **kwargs):'
     nb : NotebookNode
         The notebook that was read.
     """
+    if isinstance(fp, py3compat.string_types):
+        with io.open(fp, encoding='utf-8') as f:
+            return read(f, as_version, **kwargs)
+
     return reads(fp.read(), as_version, **kwargs)
 
 
@@ -136,14 +142,19 b' def write(nb, fp, version=NO_CONVERT, **kwargs):'
     ----------
     nb : NotebookNode
         The notebook to write.
-    fp : file
-        Any file-like object with a write method that accepts unicode.
+    fp : file or str
+        Any file-like object with a write method that accepts unicode, or
+        a path to write a file.
     version : int, optional
         The nbformat version to write.
         If nb is not this version, it will be converted.
         If unspecified, or specified as nbformat.NO_CONVERT,
         the notebook's own version will be used and no conversion performed.
     """
+    if isinstance(fp, py3compat.string_types):
+        with open(fp, 'w', encoding='utf-8') as f:
+            return write(nb, f, version=version, **kwargs)
+
     s = writes(nb, version, **kwargs)
     if isinstance(s, bytes):
         s = s.decode('utf8')

IPython/nbformat/tests/test_api.py

@@ -4,11 +4,13 b''
 # Distributed under the terms of the Modified BSD License.
 
 import json
+import os
 
 from .base import TestsBase
 
+from IPython.utils.tempdir import TemporaryDirectory
 from ..reader import get_version
-from IPython.nbformat import read, current_nbformat, writes
+from IPython.nbformat import read, current_nbformat, writes, write
 
 
 class TestAPI(TestsBase):
@@ -35,3 +37,13 b' class TestAPI(TestsBase):'
         nb2 = json.loads(jsons)
         (major, minor) = get_version(nb2)
         self.assertEqual(major, 2)
+
+    def test_read_write_path(self):
+        """read() and write() take filesystem paths"""
+        path = os.path.join(self._get_files_path(), u'test4.ipynb')
+        nb = read(path, as_version=4)
+
+        with TemporaryDirectory() as td:
+            dest = os.path.join(td, 'echidna.ipynb')
+            write(nb, dest)
+            assert os.path.isfile(dest)