python类hooks()的实例源码

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def test_requests_cm(self):
        """
        Tests whether requests can be used importing standard_library modules
        previously with the hooks context manager
        """
        code = """
            from future import standard_library
            with standard_library.hooks():
                import builtins
                import html.parser
                import http.client
            """
        with write_module(code, self.tempdir):
            import test_imports_future_stdlib
            try:
                import requests
            except ImportError:
                print("Requests doesn't seem to be available. Skipping requests test ...")
            else:
                r = requests.get('http://google.com')
                self.assertTrue(r)
            self.assertTrue(True)

def test_import_failure_from_module(self):
        """
        Tests whether e.g. "import socketserver" succeeds in a module
        imported by another module that has used and removed the stdlib hooks.
        We want this to fail; the stdlib hooks should not bleed to imported
        modules too without their explicitly invoking them.
        """
        code1 = '''
                from future import standard_library
                standard_library.install_hooks()
                standard_library.remove_hooks()
                import importme2
                '''
        code2 = '''
                import socketserver
                print('Uh oh. importme2 should have raised an ImportError.')
                '''
        self._write_test_script(code1, 'importme1.py')
        self._write_test_script(code2, 'importme2.py')
        with self.assertRaises(CalledProcessError):
            output = self._run_test_script('importme1.py')

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def detect_hooks():
    """
    Returns True if the import hooks are installed, False if not.
    """
    flog.debug('Detecting hooks ...')
    present = any([hasattr(hook, 'RENAMER') for hook in sys.meta_path])
    if present:
        flog.debug('Detected.')
    else:
        flog.debug('Not detected.')
    return present


# As of v0.12, this no longer happens implicitly:
# if not PY3:
#     install_hooks()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()

def scrub_py2_sys_modules():
    """
    Removes any Python 2 standard library modules from ``sys.modules`` that
    would interfere with Py3-style imports using import hooks. Examples are
    modules with the same names (like urllib or email).

    (Note that currently import hooks are disabled for modules like these
    with ambiguous names anyway ...)
    """
    if PY3:
        return {}
    scrubbed = {}
    for modulename in REPLACED_MODULES & set(RENAMES.keys()):
        if not modulename in sys.modules:
            continue

        module = sys.modules[modulename]

        if is_py2_stdlib_module(module):
            flog.debug('Deleting (Py2) {} from sys.modules'.format(modulename))
            scrubbed[modulename] = sys.modules[modulename]
            del sys.modules[modulename]
    return scrubbed

def install_hooks():
    """
    This function installs the future.standard_library import hook into
    sys.meta_path.
    """
    if PY3:
        return

    install_aliases()

    flog.debug('sys.meta_path was: {0}'.format(sys.meta_path))
    flog.debug('Installing hooks ...')

    # Add it unless it's there already
    newhook = RenameImport(RENAMES)
    if not detect_hooks():
        sys.meta_path.append(newhook)
    flog.debug('sys.meta_path is now: {0}'.format(sys.meta_path))

def remove_hooks(scrub_sys_modules=False):
    """
    This function removes the import hook from sys.meta_path.
    """
    if PY3:
        return
    flog.debug('Uninstalling hooks ...')
    # Loop backwards, so deleting items keeps the ordering:
    for i, hook in list(enumerate(sys.meta_path))[::-1]:
        if hasattr(hook, 'RENAMER'):
            del sys.meta_path[i]

    # Explicit is better than implicit. In the future the interface should
    # probably change so that scrubbing the import hooks requires a separate
    # function call. Left as is for now for backward compatibility with
    # v0.11.x.
    if scrub_sys_modules:
        scrub_future_sys_modules()