Deprecated since version 2.6: The imputil module has been removed in Python 3.
This module provides a very handy and useful mechanism for custom import hooks. Compared to the older ihooks 模块， imputil takes a dramatically simpler and more straight-forward approach to custom import 函数。
Manage the import process.
Install this ImportManager into the specified namespace.
Restore the previous import mechanism.
Undocumented.
Base class for replacing standard import functions.
Import a top-level module.
Find and retrieve the code for the given module.
parent specifies a parent module to define a context for importing. It may be None , indicating no particular context for the search.
modname specifies a single module (not dotted) within the parent.
fqname specifies the fully-qualified module name. This is a (potentially) dotted name from the “root” of the module namespace down to the modname.
If there is no parent, then modname==fqname.
此方法应返回 None , or a 3-tuple.
Emulate the import mechanism for built-in and frozen modules. This is a sub-class of the Importer 类。
Undocumented.
Undocumented.
Undocumented.
Undocumented.
This is a re-implementation of hierarchical module import.
This code is intended to be read, not executed. However, it does work – all you need to do to enable it is “import knee”.
(The name is a pun on the clunkier predecessor of this module, “ni”.)
import sys, imp, __builtin__ # Replacement for __import__() def import_hook(name, globals=None, locals=None, fromlist=None): parent = determine_parent(globals) q, tail = find_head_package(parent, name) m = load_tail(q, tail) if not fromlist: return q if hasattr(m, "__path__"): ensure_fromlist(m, fromlist) return m def determine_parent(globals): if not globals or not globals.has_key("__name__"): return None pname = globals['__name__'] if globals.has_key("__path__"): parent = sys.modules[pname] assert globals is parent.__dict__ return parent if '.' in pname: i = pname.rfind('.') pname = pname[:i] parent = sys.modules[pname] assert parent.__name__ == pname return parent return None def find_head_package(parent, name): if '.' in name: i = name.find('.') head = name[:i] tail = name[i+1:] else: head = name tail = "" if parent: qname = "%s.%s" % (parent.__name__, head) else: qname = head q = import_module(head, qname, parent) if q: return q, tail if parent: qname = head parent = None q = import_module(head, qname, parent) if q: return q, tail raise ImportError("No module named " + qname) def load_tail(q, tail): m = q while tail: i = tail.find('.') if i < 0: i = len(tail) head, tail = tail[:i], tail[i+1:] mname = "%s.%s" % (m.__name__, head) m = import_module(head, mname, m) if not m: raise ImportError("No module named " + mname) return m def ensure_fromlist(m, fromlist, recursive=0): for sub in fromlist: if sub == "*": if not recursive: try: all = m.__all__ except AttributeError: pass else: ensure_fromlist(m, all, 1) continue if sub != "*" and not hasattr(m, sub): subname = "%s.%s" % (m.__name__, sub) submod = import_module(sub, subname, m) if not submod: raise ImportError("No module named " + subname) def import_module(partname, fqname, parent): try: return sys.modules[fqname] except KeyError: pass try: fp, pathname, stuff = imp.find_module(partname, parent and parent.__path__) except ImportError: return None try: m = imp.load_module(fqname, fp, pathname, stuff) finally: if fp: fp.close() if parent: setattr(parent, partname, m) return m # Replacement for reload() def reload_hook(module): name = module.__name__ if '.' not in name: return import_module(name, name, None) i = name.rfind('.') pname = name[:i] parent = sys.modules[pname] return import_module(name[i+1:], name, parent) # Save the original hooks original_import = __builtin__.__import__ original_reload = __builtin__.reload # Now install our hooks __builtin__.__import__ = import_hook __builtin__.reload = reload_hook
另请参阅 importers module (which can be found in Demo/imputil/ in the Python source distribution) for additional examples.
