werkzeug.contrib.iterio
This module implements a IterIO that converts an iterator into
a stream object and the other way round. Converting streams into
iterators requires the greenlet module.
To convert an iterator into a stream all you have to do is to pass it
directly to the IterIO constructor. In this example we pass it
a newly created generator:
def foo():
yield "something\n"
yield "otherthings"
stream = IterIO(foo())
print stream.read() # read the whole iterator
The other way round works a bit different because we have to ensure that
the code execution doesn’t take place yet. An IterIO call with a
callable as first argument does two things. The function itself is passed
an IterIO stream it can feed. The object returned by the
IterIO constructor on the other hand is not an stream object but
an iterator:
def foo(stream):
stream.write("some")
stream.write("thing")
stream.flush()
stream.write("otherthing")
iterator = IterIO(foo)
print iterator.next() # prints something
print iterator.next() # prints otherthing
iterator.next() # raises StopIteration
- 2014 by the Werkzeug Team, see AUTHORS for more details.
class werkzeug.contrib.iterio.IterIO
Instances of this object implement an interface compatible with the
standard Python file object. Streams are either read-only or
write-only depending on how the object is created.
If the first argument is an iterable a file like object is returned that returns the contents of the iterable. In case the iterable is empty read operations will return the sentinel value.
If the first argument is a callable then the stream object will be
created and passed to that function. The caller itself however will
not receive a stream but an iterable. The function will be be executed
step by step as something iterates over the returned iterable. Each
call to flush() will create an item for the iterable. If
flush() is called without any writes in-between the sentinel
value will be yielded.
Note for Python 3: due to the incompatible interface of bytes and
streams you should set the sentinel value explicitly to an empty
bytestring (b'') if you are expecting to deal with bytes as
otherwise the end of the stream is marked with the wrong sentinel
value.
New in version 0.9: [UNKNOWN NODE title_reference] parameter was added.