366 lines
12 KiB
Python
366 lines
12 KiB
Python
"""Provides the Form class and related classes. Forms are a convenient
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way of building HTML forms that are composed of Widget objects.
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"""
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from quixote import get_request, get_session, get_publisher
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from quixote.html import htmltag, htmltext, TemplateIO
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from quixote.form.widget import HiddenWidget, StringWidget, TextWidget, \
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CheckboxWidget, SingleSelectWidget, RadiobuttonsWidget, \
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MultipleSelectWidget, ResetWidget, SubmitWidget, FloatWidget, \
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IntWidget, PasswordWidget
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class FormTokenWidget(HiddenWidget):
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def _parse(self, request):
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token = request.form.get(self.name)
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session = get_session()
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if not session.has_form_token(token):
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self.error = 'invalid' # this error does not get displayed
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else:
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session.remove_form_token(token)
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def render_error(self, error):
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return ''
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def render(self):
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self.value = get_session().create_form_token()
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return HiddenWidget.render(self)
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class Form(object):
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"""
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Provides a high-level mechanism for collecting and processing user
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input that is based on HTML forms.
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Instance attributes:
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widgets : [Widget]
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widgets that are not subclasses of SubmitWidget or HiddenWidget
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submit_widgets : [SubmitWidget]
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subclasses of SubmitWidget, normally rendered at the end of the
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form
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hidden_widgets : [HiddenWidget]
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subclasses of HiddenWidget, normally rendered at the beginning
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of the form
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_names : { name:string : Widget }
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names used in the form and the widgets associated with them
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"""
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TOKEN_NAME = "_form_id" # name of hidden token widget
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JAVASCRIPT_MARKUP = htmltext('<script type="text/javascript">\n'
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'<!--\n'
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'%s\n'
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'// -->\n'
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'</script>\n')
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TOKEN_NOTICE = htmltext('<div class="errornotice">'
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'The form you have submitted is invalid. Most '
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'likely it has been successfully submitted once '
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'already. Please review the the form data '
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'and submit the form again.'
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'</div>')
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ERROR_NOTICE = htmltext('<div class="errornotice">'
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'There were errors processing your form. '
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'See below for details.'
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'</div>')
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def __init__(self,
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method="post",
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action=None,
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enctype=None,
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use_tokens=True,
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**attrs):
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if method not in ("post", "get"):
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raise ValueError("Form method must be 'post' or 'get', "
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"not %r" % method)
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self.method = method
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self.action = action or self._get_default_action()
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if 'class' not in attrs:
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attrs['class'] = 'quixote'
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self.attrs = attrs
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self.widgets = []
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self.submit_widgets = []
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self.hidden_widgets = []
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self._names = {}
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if enctype is not None and enctype not in (
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"application/x-www-form-urlencoded", "multipart/form-data"):
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raise ValueError("Form enctype must be "
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"'application/x-www-form-urlencoded' or "
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"'multipart/form-data', not %r" % enctype)
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self.enctype = enctype
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if use_tokens and self.method == "post":
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config = get_publisher().config
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if config.form_tokens:
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# unique token for each form, this prevents many cross-site
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# attacks and prevents a form from being submitted twice
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self.add(FormTokenWidget, self.TOKEN_NAME, value=None)
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def _get_default_action(self):
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query = get_request().get_query()
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if query:
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return "?" + query
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else:
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return ""
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# -- Form data access methods --------------------------------------
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def __getitem__(self, name):
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"""(name:string) -> any
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Return a widget's value. Raises KeyError if widget named 'name'
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does not exist.
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"""
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try:
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return self._names[name].parse()
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except KeyError:
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raise KeyError('no widget named %r' % name)
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def __contains__(self, name):
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"""Return true if the widget named 'name' is in the form."""
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return name in self._names
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def get(self, name, default=None):
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"""(name:string, default=None) -> any
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Return a widget's value. Returns 'default' if widget named 'name'
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does not exist.
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"""
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widget = self._names.get(name)
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if widget is not None:
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return widget.parse()
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else:
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return default
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def get_widget(self, name):
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"""(name:string) -> Widget | None
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Return the widget named 'name'. Returns None if the widget does
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not exist.
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"""
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return self._names.get(name)
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def get_submit_widgets(self):
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"""() -> [SubmitWidget]
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"""
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return self.submit_widgets
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def get_all_widgets(self):
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"""() -> [Widget]
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Return all the widgets that have been added to the form. Note that
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this while this list includes submit widgets and hidden widgets, it
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does not include sub-widgets (e.g. widgets that are part of
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CompositeWidgets)
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"""
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return list(self._names.values())
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# -- Form processing and error checking ----------------------------
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def is_submitted(self):
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"""() -> bool
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Return true if a form was submitted. If the form method is 'POST'
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and the page was not requested using 'POST', then the form is not
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considered to be submitted. If the form method is 'GET' then the
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form is considered submitted if there is any form data in the
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request.
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"""
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request = get_request()
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if self.method == 'post':
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if request.get_method() == 'POST':
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return True
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else:
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return False
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else:
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return bool(request.form)
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def has_errors(self):
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"""() -> bool
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Ensure that all components of the form have parsed themselves. Return
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true if any of them have errors.
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"""
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request = get_request()
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has_errors = False
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if self.is_submitted():
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for widget in self.get_all_widgets():
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if widget.has_error(request=request):
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has_errors = True
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return has_errors
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def clear_errors(self):
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"""Ensure that all components of the form have parsed themselves.
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Clear any errors that might have occured during parsing.
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"""
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request = get_request()
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for widget in self.get_all_widgets():
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widget.clear_error(request)
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def get_submit(self):
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"""() -> string | bool
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Get the name of the submit button that was used to submit the
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current form. If the form is submitted but not by any known
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SubmitWidget then return True. Otherwise, return False.
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"""
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request = get_request()
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for button in self.submit_widgets:
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if button.parse(request):
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return button.name
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else:
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if self.is_submitted():
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return True
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else:
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return False
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def set_error(self, name, error):
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"""(name : string, error : string)
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Set the error attribute of the widget named 'name'.
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"""
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widget = self._names.get(name)
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if not widget:
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raise KeyError("unknown name %r" % name)
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widget.set_error(error)
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# -- Form population methods ---------------------------------------
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def add(self, widget_class, name, *args, **kwargs):
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if name in self._names:
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raise ValueError("form already has '%s' widget" % name)
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# add 'id' attribute if not already present
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if 'id' not in kwargs:
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kwargs['id'] = name
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kwargs['form'] = self
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widget = widget_class(name, *args, **kwargs)
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self._names[name] = widget
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if isinstance(widget, SubmitWidget):
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self.submit_widgets.append(widget) # will be rendered at end
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elif isinstance(widget, HiddenWidget):
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self.hidden_widgets.append(widget) # will be render at beginning
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else:
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self.widgets.append(widget)
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# convenience methods
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def add_submit(self, name, value=None, **kwargs):
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self.add(SubmitWidget, name, value, **kwargs)
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def add_reset(self, name, value=None, **kwargs):
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self.add(ResetWidget, name, value, **kwargs)
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def add_hidden(self, name, value=None, **kwargs):
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self.add(HiddenWidget, name, value, **kwargs)
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def add_string(self, name, value=None, **kwargs):
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self.add(StringWidget, name, value, **kwargs)
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def add_text(self, name, value=None, **kwargs):
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self.add(TextWidget, name, value, **kwargs)
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def add_password(self, name, value=None, **kwargs):
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self.add(PasswordWidget, name, value, **kwargs)
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def add_checkbox(self, name, value=None, **kwargs):
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self.add(CheckboxWidget, name, value, **kwargs)
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def add_single_select(self, name, value=None, **kwargs):
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self.add(SingleSelectWidget, name, value, **kwargs)
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def add_multiple_select(self, name, value=None, **kwargs):
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self.add(MultipleSelectWidget, name, value, **kwargs)
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def add_radiobuttons(self, name, value=None, **kwargs):
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self.add(RadiobuttonsWidget, name, value, **kwargs)
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def add_float(self, name, value=None, **kwargs):
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self.add(FloatWidget, name, value, **kwargs)
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def add_int(self, name, value=None, **kwargs):
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self.add(IntWidget, name, value, **kwargs)
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# -- Layout (rendering) methods ------------------------------------
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def render(self):
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"""() -> HTML text
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Render a form as HTML.
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"""
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r = TemplateIO(html=True)
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r += self._render_start()
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r += self._render_body()
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r += self._render_finish()
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return r.getvalue()
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def _render_start(self):
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r = TemplateIO(html=True)
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r += htmltag('form', method=self.method,
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enctype=self.enctype, action=self.action,
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**self.attrs)
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r += self._render_hidden_widgets()
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return r.getvalue()
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def _render_finish(self):
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r = TemplateIO(html=True)
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r += htmltext('</form><br class="quixoteform" />')
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code = get_request().response.javascript_code
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if code:
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r += self._render_javascript(code)
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return r.getvalue()
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def _render_widgets(self):
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r = TemplateIO(html=True)
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for widget in self.widgets:
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r += widget.render()
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return r.getvalue()
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def _render_hidden_widgets(self):
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r = TemplateIO(html=True)
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for widget in self.hidden_widgets:
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r += widget.render()
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return r.getvalue()
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def _render_submit_widgets(self):
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r = TemplateIO(html=True)
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if self.submit_widgets:
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r += htmltext('<div class="submit">')
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for widget in self.submit_widgets:
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r += widget.render()
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r += htmltext('</div><br class="submit" />')
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return r.getvalue()
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def _render_error_notice(self):
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token_widget = self.get_widget(self.TOKEN_NAME)
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if token_widget is not None and token_widget.has_error():
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# form tokens are enabled but the token data in the request
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# does not match anything in the session. It could be an
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# a cross-site attack but most likely the back button has
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# be used
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return self.TOKEN_NOTICE
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else:
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return self.ERROR_NOTICE
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def _render_javascript(self, javascript_code):
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"""Render javacript code for the form. Insert code lexically
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sorted by code_id.
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"""
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form_code = []
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code_ids = sorted(javascript_code.keys())
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for code_id in code_ids:
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code = javascript_code[code_id]
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if code:
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form_code.append(code)
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javascript_code[code_id] = ''
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if form_code:
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return self.JAVASCRIPT_MARKUP % htmltext(''.join(form_code))
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else:
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return ''
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def _render_body(self):
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r = TemplateIO(html=True)
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if self.has_errors():
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r += self._render_error_notice()
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r += self._render_widgets()
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r += self._render_submit_widgets()
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return r.getvalue()
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