import_notebooks.py

#!/usr/bin/env python
# Settings and definitions for fuzzingbook notebooks

# We want to import notebooks as modules
# Source: http://jupyter-notebook.readthedocs.io/en/stable/examples/Notebook/Importing%20Notebooks.html

import io, os, sys, types, re
from IPython import get_ipython
from nbformat import read
from IPython.core.interactiveshell import InteractiveShell
import linecache
import ast

# To avoid re-running notebook computations during import,
# we only import code cells that match this regular expression
# i.e. definitions of functions, classes, UPPERCASE_VARIABLES, and imports
RE_CODE = re.compile(r"^(def |class |@|[A-Z0-9_]* = |import |from )")

def find_notebook(fullname, path=None):
    """find a notebook, given its fully qualified name and an optional path

    This turns "foo.bar" into "foo/bar.ipynb"
    and tries turning "Foo_Bar" into "Foo Bar" if Foo_Bar
    does not exist.
    """
    name = fullname.rsplit('.', 1)[-1]
    if not path:
        path = ['']
    for d in path:
        nb_path = os.path.join(d, name + ".ipynb")
        if os.path.isfile(nb_path):
            return nb_path
        # let import Notebook_Name find "Notebook Name.ipynb"
        nb_path = nb_path.replace("_", " ")
        if os.path.isfile(nb_path):
            return nb_path

class NotebookLoader(object):
    """Module Loader for Jupyter Notebooks"""
    def __init__(self, path=None):
        self.shell = InteractiveShell.instance()
        self.path = path
        self.lines = {}

    def load_module(self, fullname):
        self.lines[fullname] = ''
        """import a notebook as a module"""
        path = find_notebook(fullname, self.path)

        # print ("importing Jupyter notebook from %s" % path)

        # load the notebook object
        with io.open(path, 'r', encoding='utf-8') as f:
            nb = read(f, 4)


        # create the module and add it to sys.modules
        # if name in sys.modules:
        #    return sys.modules[name]
        mod = types.ModuleType(fullname)
        mod.__file__ = path
        mod.__loader__ = self
        mod.__dict__['get_ipython'] = get_ipython
        sys.modules[fullname] = mod

        # extra work to ensure that magics that would affect the user_ns
        # actually affect the notebook module's ns
        save_user_ns = self.shell.user_ns
        self.shell.user_ns = mod.__dict__


        codecells = [self.shell.input_transformer_manager.transform_cell(cell.source)
                              for cell in nb.cells if cell.cell_type == 'code']
        source = [code for code in codecells if RE_CODE.match(code)]

        lno = 1

        try:
            for code in source:
                parsed = ast.parse(code, filename=path, mode='exec')
                ast.increment_lineno(parsed, n=lno)
                exec(compile(parsed, path, 'exec'), mod.__dict__)
                lno += len(code.split('\n'))
            self.lines[fullname] = '\n'.join(source)
            p = len(self.lines[fullname].split('\n')) + 1
            assert lno == p
    
        finally:
            self.shell.user_ns = save_user_ns
            data = self.lines[fullname]
            linecache.cache[path] = (len(data), None,
                                    [line+'\n' for line in data.splitlines()],
                                    fullname)
        return mod

class NotebookFinder(object):
    """Module finder that locates Jupyter Notebooks"""
    def __init__(self):
        self.loaders = {}

    def find_module(self, fullname, path=None):
        nb_path = find_notebook(fullname, path)
        if not nb_path:
            return

        key = path
        if path:
            # lists aren't hashable
            key = os.path.sep.join(path)

        if key not in self.loaders:
            self.loaders[key] = NotebookLoader(path)
        return self.loaders[key]

sys.meta_path.append(NotebookFinder())