我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用future.standard_library.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 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 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 __enter__(self): # flog.debug('Entering hooks context manager') self.old_sys_modules = copy.copy(sys.modules) self.hooks_were_installed = detect_hooks() # self.scrubbed = scrub_py2_sys_modules() install_hooks() return self
def __exit__(self, *args): # flog.debug('Exiting hooks context manager') # restore_sys_modules(self.scrubbed) if not self.hooks_were_installed: remove_hooks() # scrub_future_sys_modules() # Sanity check for is_py2_stdlib_module(): We aren't replacing any # builtin modules names:
def cache_py2_modules(): """ Currently this function is unneeded, as we are not attempting to provide import hooks for modules with ambiguous names: email, urllib, pickle. """ if len(sys.py2_modules) != 0: return assert not detect_hooks() import urllib sys.py2_modules['urllib'] = urllib import email sys.py2_modules['email'] = email import pickle sys.py2_modules['pickle'] = pickle # Not all Python installations have test module. (Anaconda doesn't, for example.) # try: # import test # except ImportError: # sys.py2_modules['test'] = None # sys.py2_modules['test'] = test # import dbm # sys.py2_modules['dbm'] = dbm
def test_urllib(self): """ Tests that urllib isn't changed from under our feet. (This might not even be a problem?) """ from future import standard_library import urllib orig_file = urllib.__file__ with standard_library.hooks(): import urllib.response self.assertEqual(orig_file, urllib.__file__)
def test_urllib_imports_cm(self): with standard_library.hooks(): import urllib import urllib.parse import urllib.request import urllib.robotparser import urllib.error import urllib.response self.assertTrue(True)
