1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
|
.. _views_chapter:
Views
=====
A :term:`view` is a callable which is invoked when a request enters
your application. :mod:`repoze.bfg's` primary job is to find and call
a view when a :term:`request` reaches it. The view's return value
must implement the :term:`WebOb` ``Response`` object interface.
.. _function_as_view:
Defining a View as a Function
-----------------------------
The easiest way to define a view is to create a function that accepts
two arguments: :term:`context`, and :term:`request`. For example,
this is a hello world view implemented as a function:
.. code-block:: python
:linenos:
from webob import Response
def hello_world(context, request):
return Response('Hello world!')
The :term:`context` and :term:`request` arguments passed to a view
function can be defined as follows:
context
An instance of a model found via graph :term:`traversal` or
:term:`URL dispatch`.
request
A WebOb request object representing the current WSGI request.
.. _class_as_view:
Defining a View as a Class
--------------------------
.. note:: This feature is new as of :mod:`repoze.bfg` 0.8.1.
When a view callable is a class, the calling semantics are slightly
different than when it is a function or another non-class callable.
When a view is a class, the class' ``__init__`` is called with the
context and the request parameters. As a result, an instance of the
class is created. Subsequently, that instance's ``__call__`` method
is invoked with no parameters. The class' ``__call__`` method must
return a response. This provides behavior similar to a Zope 'browser
view' (Zope 'browser views' are typically classes instead of simple
callables). So the simplest class that can be a view must have:
- an ``__init__`` method that accepts a ``context`` and a ``request``
as positional arguments.
- a ``__call__`` method that accepts no parameters and returns a
response.
For example:
.. code-block:: python
:linenos:
from webob import Response
class MyView(object):
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self):
return Response('hello from %r!' % self.context)
The context and request objects passed to ``__init__`` are the same
types of objects as described in :ref:`function_as_view`.
The Response
------------
A view callable must return an object that implements the
:term:`WebOb` ``Response`` interface. The easiest way to return
something that implements this interface is to return a
``webob.Response`` object. But any object that has the following
attributes will work:
status
The HTTP status code (including the name) for the response.
E.g. ``200 OK`` or ``401 Unauthorized``.
headerlist
A sequence of tuples representing the list of headers that should be
set in the response. E.g. ``[('Content-Type', 'text/html'),
('Content-Length', '412')]``
app_iter
An iterable representing the body of the response. This can be a
list, e.g. ``['<html><head></head><body>Hello
world!</body></html>']`` or it can be a filelike object, or any
other sort of iterable.
If a view happens to return something to the :mod:`repoze.bfg`
publisher that does not implement this interface, the publisher will
raise an error.
.. _mapping_views_to_urls_using_zcml_section:
Mapping Views to URLs Using ZCML
--------------------------------
You may associate a view with a URL by adding information to your
:term:`application registry` via :term:`ZCML` in your
``configure.zcml`` file using a ``view`` declaration.
.. code-block:: xml
:linenos:
<view
for=".models.Hello"
view=".views.hello_world"
name="hello.html"
/>
The above maps the ``.views.hello_world`` view function to
:term:`context` objects which are instances (or subclasses) of the
Python class represented by ``.models.Hello`` when the *view name* is
``hello.html``.
.. note:: Values prefixed with a period (``.``) for the ``for`` and
``view`` attributes of a ``view`` (such as those above) mean
"relative to the Python package directory in which this
:term:`ZCML` file is stored". So if the above ``view``
declaration was made inside a ``configure.zcml`` file that lived in
the ``hello`` package, you could replace the relative
``.models.Hello`` with the absolute ``hello.models.Hello``;
likewise you could replace the relative ``.views.hello_world`` with
the absolute ``hello.views.hello_world``. Either the relative or
absolute form is functionally equivalent. It's often useful to use
the relative form, in case your package's name changes. It's also
shorter to type.
You can also declare a *default view* for a model type:
.. code-block:: xml
:linenos:
<view
for=".models.Hello"
view=".views.hello_world"
/>
A *default view* has no ``name`` attribute. When a :term:`context` is
traversed and there is no *view name* in the request, the *default
view* is the view that is used.
You can also declare that a view is good for any model type by using
the special ``*`` character in the ``for`` attribute:
.. code-block:: xml
:linenos:
<view
for="*"
view=".views.hello_world"
name="hello.html"
/>
This indicates that when :mod:`repoze.bfg` identifies that the *view
name* is ``hello.html`` against *any* :term:`context`, this view will
be called.
A ZCML ``view`` declaration's ``view`` attribute can also name a
class. In this case, the rules described in :ref:`class_as_view`
apply for the class which is named.
The ``view`` ZCML Directive
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The ``view`` ZCML directive has these possible attributes:
view
The Python dotted-path name to the view callable.
for
A Python dotted-path name representing the Python class that the
:term:`context` must be an instance of, *or* the :term:`interface`
that the :term:`context` must provide in order for this view to be
found and called.
name
The *view name*. Read and understand :ref:`traversal_chapter` to
understand the concept of a view name.
permission
The name of a *permission* that the user must possess in order to
call the view. See :ref:`view_security_section` for more
information about view security and permissions.
request_type
This value can either be one of the strings 'GET', 'POST', 'PUT',
'DELETE', or 'HEAD' representing an HTTP method, *or* it may be
Python dotted-path string representing the :term:`interface` that
the :term:`request` must have in order for this view to be found and
called. See :ref:`view_request_types_section` for more information
about request types.
.. _mapping_views_to_urls_using_a_decorator_section:
Mapping Views to URLs Using a Decorator
---------------------------------------
If you're allergic to reading and writing :term:`ZCML`, or you're just
more comfortable defining your view declarations using Python, you may
use the ``repoze.bfg.view.bfg_view`` decorator to associate your view
functions with URLs instead of using :term:`ZCML` for the same
purpose. ``repoze.bfg.view.bfg_view`` can be used to associate
``for``, ``name``, ``permission`` and ``request_type`` information --
as done via the equivalent ZCML -- with a function that acts as a
:mod:`repoze.bfg` view.
To make :mod:`repoze.bfg` process your ``bfg_view`` declarations, you
*must* insert the following boilerplate into your application's
``configure.zcml``::
<scan package="."/>
After you do so, you will not need to use any other ZCML to configure
:mod:`repoze.bfg` view declarations. Instead, you will use a
decorator to do this work.
.. warning:: using this feature tends to slows down application
startup slightly, as more work is performed at application startup
to scan for view declarations. Also, if you use decorators, it
means that other people will not be able to override your view
declarations externally using ZCML: this is a common requirement if
you're developing an exensible application (e.g. a framework).
The ``bfg_view`` Decorator
~~~~~~~~~~~~~~~~~~~~~~~~~~
``repoze.bfg.view.bfg_view`` is a decorator which allows Python code
to make view registrations instead of using ZCML for the same purpose.
An example might reside in a bfg application module ``views.py``:
.. code-block:: python
:linenos:
from models import MyModel
from repoze.bfg.view import bfg_view
from repoze.bfg.chameleon_zpt import render_template_to_response
@bfg_view(name='my_view', request_type='POST', for_=MyModel,
permission='read')
def my_view(context, request):
return render_template_to_response('templates/my.pt')
Using this decorator as above replaces the need to add this ZCML to
your application registry:
.. code-block:: xml
:linenos:
<view
for=".models.MyModel"
view=".views.my_view"
name="my_view"
permission="read"
request_type="POST"
/>
All arguments to ``bfg_view`` are optional.
If ``name`` is not supplied, the empty string is used (implying
the default view).
If ``request_type`` is not supplied, the interface ``None`` is used,
implying any request type.
If ``for_`` is not supplied, the interface
``zope.interface.Interface`` (which matches any model) is used.
``for_`` can also name a class, like its ZCML brother.
If ``permission`` is not supplied, no permission is registered for
this view (it's accessible by any caller).
All arguments may be omitted. For example:
.. code-block:: python
:linenos:
from webob import Response
@bfg_view()
def my_view(context, request):
""" My view """
return Response()
Such a registration as the one directly above implies that the view
name will be ``my_view``, registered ``for_`` any model type, using no
permission, registered against requests which implement any request
method or interface.
If your view callable is a class, the ``bfg_view`` decorator can also
be used as a class decorator in Python 2.6 and better (Python 2.5 and
below do not support class decorators). All the arguments to the
decorator are the same when applied against a class as when they are
applied against a function. For example:
.. code-block:: python
:linenos:
from webob import Response
from repoze.bfg.view import bfg_view
@bfg_view()
class MyView(object):
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self):
return Response('hello from %s!' % self.context)
You can use the ``bfg_view`` decorator as a simple callable to
manually decorate classes in Python 2.5 and below (without the
decorator syntactic sugar), if you wish:
.. code-block:: python
:linenos:
from webob import Response
from repoze.bfg.view import bfg_view
class MyView(object):
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self):
return Response('hello from %s!' % self.context)
my_view = bfg_view()(MyView)
.. _using_model_interfaces:
Using Model Interfaces
----------------------
Instead of registering your views ``for`` a Python model *class*, you
can optionally register a view for an :term:`interface`. Since an
interface can be attached arbitrarily to any model instance (as
opposed to its identity being implied by only its class), associating
a view with an interface can provide more flexibility for sharing a
single view between two or more different implementations of a model
type. For example, if two model object instances of different Python
class types share the same interface, you can use the same view
against each of them.
In order to make use of interfaces in your application during view
dispatch, you must create an interface and mark up your model classes
or instances with interface declarations that refer to this interface.
To attach an interface to a model *class*, you define the interface
and use the ``zope.interface.implements`` function to associate the
interface with the class.
.. code-block:: python
:linenos:
from zope.interface import Interface
from zope.interface import implements
class IHello(Interface):
""" A marker interface """
class Hello(object):
implements(IHello)
To attach an interface to a model *instance*, you define the interface
and use the ``zope.interface.alsoProvides`` function to associate the
interface with the instance. This function mutates the instance in
such a way that the interface is attached to it.
.. code-block:: python
:linenos:
from zope.interface import Interface
from zope.interface import alsoProvides
class IHello(Interface):
""" A marker interface """
class Hello(object):
pass
def make_hello():
hello = Hello()
alsoProvides(hello, IHello)
return hello
Regardless of how you associate an interface with a model instance or
a model class, the resulting ZCML to associate that interface with a
view is the same. Assuming the above code that defines an ``IHello``
interface lives in the root of your application, and its module is
named "models.py", the below interface declaration will associate the
``.views.hello_world`` view with models that implement (aka provide)
this interface.
.. code-block:: xml
:linenos:
<view
for=".models.IHello"
view=".views.hello_world"
name="hello.html"
/>
Any time a model that is determined to be the :term:`context` provides
this interface, and a view named ``hello.html`` is looked up against
it as per the URL, the ``.views.hello_world`` view will be invoked.
Note that views registered against a model class take precedence over
views registered for any interface the model class implements when an
ambiguity arises. If a view is registered for both the class type of
the context and an interface implemented by the context's class, the
view registered for the context's class will "win".
See :term:`Interface` in the glossary to find more information about
interfaces.
.. _view_request_types_section:
Standard View Request Types
---------------------------
You can optionally add a *request_type* attribute to your ``view``
declaration or ``bfg_view`` decorator, which indicates what "kind" of
request the view should be used for. If the request type for a
request doesn't match the request type that a view defines as its
``request_type`` argument, that view won't be called.
The request type can be one of the strings 'GET', 'POST', 'PUT',
'DELETE', or 'HEAD'. When the request type is one of these strings,
the view will only be called when the HTTP method of a request matches
this type.
For example, the following bit of ZCML will match an HTTP POST
request:
.. code-block:: xml
:linenos:
<view
for=".models.Hello"
view=".views.handle_post"
name="handle_post"
request_type="POST"
/>
A ``bfg_view`` decorator that does the same as the above ZCML ``view``
declaration which matches only on HTTP POST might look something like:
.. code-block:: python
:linenos:
from myproject.models import Hello
from webob import Response
@bfg_view(for=Hello, request_type='POST')
def handle_post(context, request):
return Response('hello'
The above examples register views for the POST request type, so it
will only be called if the request's HTTP method is ``POST``. Even if
all the other specifiers match (e.g. the model type is the class
``.models.Hello``, and the view_name is ``handle_post``), if the
request verb is not POST, it will not be invoked. This provides a way
to ensure that views you write are only called via specific HTTP
verbs.
The least specific request type is ``None``. All requests are
guaranteed to implement this request type. It is also the default
request type for views that omit a ``request_type`` argument.
Custom View Request Types
-------------------------
You can make use of *custom* view request types by attaching an
:term:`interface` to the request and specifying this interface in the
``request_type`` parameter. For example, you might want to make use
of simple "content negotiation", only invoking a particular view if
the request has a content-type of 'application/json'.
For information about using interface to specify a request type, see
:ref:`using_an_event_to_vary_the_request_type`.
.. _view_security_section:
View Security
-------------
If a :term:`authentication policy` (and a :term:`authorization
policy`) is active, any :term:`permission` attached to a ``view``
declaration will be consulted to ensure that the currently
authenticated user possesses that permission against the context
before the view function is actually called. Here's an example of
specifying a permission in a ``view`` declaration:
.. code-block:: xml
:linenos:
<view
for=".models.IBlog"
view=".views.add_entry"
name="add.html"
permission="add"
/>
When an authentication policy is enabled, this view will be protected
with the ``add`` permission. The view will *not be called* if the
user does not possess the ``add`` permission relative to the current
:term:`context` and an authorization policy is enabled. Instead an
HTTP ``Unauthorized`` status will be returned to the client.
.. note::
See the :ref:`security_chapter` chapter to find out how to turn on
an authentication policy.
.. note::
Packages such as :term:`repoze.who` are capable of intercepting an
``Unauthorized`` response and displaying a form that asks a user to
authenticate. Use this kind of package to ask the user for
authentication credentials.
Using a View to Do A HTTP Redirect
----------------------------------
You can issue an HTTP redirect from within a view by returning a
slightly different response.
.. code-block:: python
:linenos:
from webob.exc import HTTPFound
def myview(context, request):
return HTTPFound(location='http://example.com')
All exception types from the :mod:`webob.exc` module implement the
``IResponse`` interface; any can be returned as the response from a
view. See :term:`WebOb` for the documentation for this module; it
includes other response types for Unauthorized, etc.
.. _static_resources_section:
Serving Static Resources Using a View
-------------------------------------
Using the :mod:`repoze.bfg.view` ``static`` helper class is the
preferred way to serve static resources (like JavaScript and CSS
files) within :mod:`repoze.bfg`. This class creates a callable that
is capable acting as a :mod:`repoze.bfg` view which serves static
resources from a directory. For instance, to serve files within a
directory located on your filesystem at ``/path/to/static/dir``
mounted at the URL path ``/static`` in your application, create an
instance of :mod:`repoze.bfg.view` 's ``static`` class inside a
``static.py`` file in your application root as below.
.. code-block:: python
:linenos:
from repoze.bfg.view import static
static_view = static('/path/to/static/dir')
Subsequently, wire this view up to be accessible as ``/static`` using
ZCML in your application's ``configure.zcml`` against either the class
or interface that represents your root object.
.. code-block:: xml
:linenos:
<view
for=".models.Root"
view=".static.static_view"
name="static"
/>
In this case, ``.models.Root`` refers to the class of which your
:mod:`repoze.bfg` application's root object is an instance.
.. note:: You can also give a ``for`` of ``*`` if you want the name
``static`` to be accessible as the static view against any model.
This will also allow ``/static/foo.js`` to work, but it will allow
for ``/anything/static/foo.js`` too, as long as ``anything`` itself
is resolveable.
Now put your static files (JS, etc) on your filesystem in the
directory represented as ``/path/to/static/dir``. After this is done,
you should be able to view the static files in this directory via a
browser at URLs prefixed with ``/static/``, for instance
``/static/foo.js`` will return the file
``/path/to/static/dir/foo.js``. The static directory may contain
subdirectories recursively, and any subdirectories may hold files;
these will be resolved by the static view as you would expect.
.. note:: To ensure that model objects contained in the root don't
"shadow" your static view (model objects take precedence during
traversal), or to ensure that your root object's ``__getitem__`` is
never called when a static resource is requested, you can refer to
your static resources as registered above in URLs as,
e.g. ``/@@static/foo.js``. This is completely equivalent to
``/static/foo.js``. See :ref:`traversal_chapter` for information
about "goggles" (``@@``).
.. note:: Under the hood, the ``repoze.bfg.view.static`` class employs
the ``urlparser.StaticURLParser`` WSGI application to serve static
files. See `the Paste documentation for urlparser
<http://pythonpaste.org/modules/urlparser.html>`_ for more
information about ``urlparser.StaticURLParser``.
Using Views to Handle Form Submissions (Unicode and Character Set Issues)
-------------------------------------------------------------------------
Most web applications need to accept form submissions from web
browsers and various other clients. In :mod:`repoze.bfg`, form
submission handling logic is always part of a :term:`view`. For a
general overview of how to handle form submission data using the
:term:`WebOb` API, see `"Query and POST variables" within the WebOb
documentation
<http://pythonpaste.org/webob/reference.html#query-post-variables>`_.
:mod:`repoze.bfg` defers to WebOb for its request and response
implementations, and handling form submission data is a property of
the request implementation. Understanding WebOb's request API is the
key to understanding how to process form submission data.
There are some defaults that you need to be aware of when trying to
handle form submission data in a :mod:`repoze.bfg` view. Because
having high-order (non-ASCII) characters in data contained within form
submissions is exceedingly common, and because the UTF-8 encoding is
the most common encoding used on the web for non-ASCII character data,
and because working and storing Unicode values is much saner than
working with an storing bytestrings, :mod:`repoze.bfg` configures the
:term:`WebOb` request machinery to attempt to decode form submission
values into Unicode from the UTF-8 character set implicitly. This
implicit decoding happens when view code obtains form field values via
the :term:`WebOb` ``request.params``, ``request.GET``, or
``request.POST`` APIs.
For example, let's assume that the following form page is served up to
a browser client, and its ``action`` points at some :mod:`repoze.bfg`
view code:
.. code-block:: xml
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
</head>
<form method="POST" action="myview">
<div>
<input type="text" name="firstname"/>
</div>
<div>
<input type="text" name="lastname"/>
</div>
<input type="submit" value="Submit"/>
</form>
</html>
The ``myview`` view code in the :mod:`repoze.bfg` application *must*
expect that the values returned by ``request.params`` will be of type
``unicode``, as opposed to type ``str``. The following will work to
accept a form post from the above form:
.. code-block:: python
def myview(context, request):
firstname = request.params['firstname']
lastname = request.params['lastname']
But the following ``myview`` view code *may not* work, as it tries to
decode already-decoded (``unicode``) values obtained from
``request.params``:
.. code-block:: python
def myview(context, request):
# the .decode('utf-8') will break below if there are any high-order
# characters in the firstname or lastname
firstname = request.params['firstname'].decode('utf-8')
lastname = request.params['lastname'].decode('utf-8')
For implicit decoding to work reliably, you must ensure that every
form you render that posts to a :mod:`repoze.bfg` view is rendered via
a response that has a ``;charset=UTF-8`` in its ``Content-Type``
header; or, as in the form above, with a ``meta http-equiv`` tag that
implies that the charset is UTF-8 within the HTML ``head`` of the page
containing the form. This must be done explicitly because all known
browser clients assume that they should encode form data in the
character set implied by ``Content-Type`` value of the response
containing the form when subsequently submitting that form; there is
no other generally accepted way to tell browser clients which charset
to use to encode form data. If you do not specify an encoding
explicitly, the browser client will choose to encode form data in its
default character set before submitting it. The browser client may
have a non-UTF-8 default encoding. If such a request is handled by
your view code, when the form submission data is encoded in a non-UTF8
charset, eventually the WebOb request code accessed within your view
will throw an error when it can't decode some high-order character
encoded in another character set within form data e.g. when
``request.params['somename']`` is accessed.
If you are using the ``webob.Response`` class to generate a response,
or if you use the ``render_template``* templating APIs, the UTF-8
charset is set automatically as the default via the ``Content-Type``
header. If you return a ``Content-Type`` header without an explicit
charset, a WebOb request will add a ``;charset=utf-8`` trailer to the
``Content-Type`` header value for you for response content types that
are textual (e.g. ``text/html``, ``application/xml``, etc) as it is
rendered. If you are using your own response object, you will need to
ensure you do this yourself.
To avoid implicit form submission value decoding, so that the values
returned from ``request.params``, ``request.GET`` and ``request.POST``
are returned as bytestrings rather than Unicode, add the following to
your application's ``configure.zcml``::
<subscriber for="repoze.bfg.interfaces.INewRequest"
handler="repoze.bfg.request.make_request_ascii"/>
You can then control form post data decoding "by hand" as necessary.
For example, when this subscriber is active, the second example above
will work unconditionally as long as you ensure that your forms are
rendered in a request that has a ``;charset=utf-8`` stanza on its
``Content-Type`` header.
.. note:: The behavior that form values are decoded from UTF-8 to
Unicode implicitly was introduced in :mod:`repoze.bfg` 0.7.0.
Previous versions of :mod:`repoze.bfg` performed no implicit
decoding of form values (the default was to treat values as
bytestrings).
.. note:: Only the *values* of request params obtained via
``request.params``, ``request.GET`` or ``request.POST`` are decoded
to Unicode objects implicitly in :mod:`repoze.bfg`'s default
configuration. The keys are still strings.
|