tornado.util
— General-purpose utilities¶
Miscellaneous utility functions and classes.
This module is used internally by Tornado. It is not necessarily expected that the functions and classes defined here will be useful to other applications, but they are documented here in case they are.
The one public-facing part of this module is the Configurable
class
and its configure
method, which becomes a part of the
interface of its subclasses, including AsyncHTTPClient
, IOLoop
,
and Resolver
.
-
class
tornado.util.
ObjectDict
[source]¶ Makes a dictionary behave like an object, with attribute-style access.
-
class
tornado.util.
GzipDecompressor
[source]¶ Streaming gzip decompressor.
The interface is like that of
zlib.decompressobj
(without the optional arguments, but it understands gzip headers and checksums.
-
tornado.util.
import_object
(name)[source]¶ Imports an object by name.
import_object(‘x’) is equivalent to ‘import x’. import_object(‘x.y.z’) is equivalent to ‘from x.y import z’.
>>> import tornado.escape >>> import_object('tornado.escape') is tornado.escape True >>> import_object('tornado.escape.utf8') is tornado.escape.utf8 True >>> import_object('tornado') is tornado True >>> import_object('tornado.missing_module') Traceback (most recent call last): ... ImportError: No module named missing_module
-
class
tornado.util.
Configurable
[source]¶ Base class for configurable interfaces.
A configurable interface is an (abstract) class whose constructor acts as a factory function for one of its implementation subclasses. The implementation subclass as well as optional keyword arguments to its initializer can be set globally at runtime with
configure
.By using the constructor as the factory method, the interface looks like a normal class,
isinstance
works as usual, etc. This pattern is most useful when the choice of implementation is likely to be a global decision (e.g. whenepoll
is available, always use it instead ofselect
), or when a previously-monolithic class has been split into specialized subclasses.Configurable subclasses must define the class methods
configurable_base
andconfigurable_default
, and use the instance methodinitialize
instead of__init__
.-
classmethod
configurable_base
()[source]¶ Returns the base class of a configurable hierarchy.
This will normally return the class in which it is defined. (which is not necessarily the same as the cls classmethod parameter).
-
classmethod
configurable_default
()[source]¶ Returns the implementation class to be used if none is configured.
-
initialize
()[source]¶ Initialize a
Configurable
subclass instance.Configurable classes should use
initialize
instead of__init__
.
-
classmethod
-
class
tornado.util.
ArgReplacer
(func, name)[source]¶ Replaces one value in an
args, kwargs
pair.Inspects the function signature to find an argument by name whether it is passed by position or keyword. For use in decorators and similar wrappers.
-
replace
(new_value, args, kwargs)[source]¶ Replace the named argument in
args, kwargs
withnew_value
.Returns
(old_value, args, kwargs)
. The returnedargs
andkwargs
objects may not be the same as the input objects, or the input objects may be mutated.If the named argument was not found,
new_value
will be added tokwargs
and None will be returned asold_value
.
-