tailbone/tailbone/forms2/core.py

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# -*- coding: utf-8; -*-
################################################################################
#
# Rattail -- Retail Software Framework
# Copyright © 2010-2017 Lance Edgar
#
# This file is part of Rattail.
#
# Rattail is free software: you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# Rattail. If not, see <http://www.gnu.org/licenses/>.
#
################################################################################
"""
Forms Core
"""
from __future__ import unicode_literals, absolute_import
import logging
import six
import sqlalchemy as sa
from sqlalchemy import orm
from sqlalchemy.ext.associationproxy import AssociationProxy, ASSOCIATION_PROXY
from rattail.util import prettify
import colander
from colanderalchemy import SQLAlchemySchemaNode
import deform
from deform import widget as dfwidget
from pyramid.renderers import render
from webhelpers2.html import tags, HTML
log = logging.getLogger(__name__)
class CustomSchemaNode(SQLAlchemySchemaNode):
def get_schema_from_relationship(self, prop, overrides):
""" Build and return a :class:`colander.SchemaNode` for a relationship.
"""
# for some reason ColanderAlchemy wants to crawl our entire ORM by
# default, by way of relationships. this 'excludes' hack is used to
# prevent that, by forcing skip of 2nd-level relationships
excludes = []
if isinstance(prop, orm.RelationshipProperty):
for next_prop in prop.mapper.iterate_properties:
if isinstance(next_prop, orm.RelationshipProperty):
excludes.append(next_prop.key)
if excludes:
overrides['excludes'] = excludes
return super(CustomSchemaNode, self).get_schema_from_relationship(prop, overrides)
def dictify(self, obj):
""" Return a dictified version of `obj` using schema information.
.. note::
This method was copied from upstream and modified to add automatic
handling of "association proxy" fields.
"""
dict_ = super(CustomSchemaNode, self).dictify(obj)
for node in self:
name = node.name
if name not in dict_:
try:
desc = getattr(self.inspector.all_orm_descriptors, name)
if desc.extension_type != ASSOCIATION_PROXY:
continue
value = getattr(obj, name)
except AttributeError:
continue
if value is None:
if isinstance(node.typ, colander.String):
# colander has an issue with `None` on a String type
# where it translates it into "None". Let's check
# for that specific case and turn it into a
# `colander.null`.
dict_[name] = colander.null
else:
# A specific case this helps is with Integer where
# `None` is an invalid value. We call serialize()
# to test if we have a value that will work later
# for serialization and then allow it if it doesn't
# raise an exception. Hopefully this also catches
# issues with user defined types and future issues.
try:
node.serialize(value)
except:
dict_[name] = colander.null
else:
dict_[name] = value
else:
dict_[name] = value
return dict_
def objectify(self, dict_, context=None):
""" Return an object representing ``dict_`` using schema information.
.. note::
This method was copied from upstream and modified to add automatic
handling of "association proxy" fields.
"""
mapper = self.inspector
context = mapper.class_() if context is None else context
for attr in dict_:
if mapper.has_property(attr):
prop = mapper.get_property(attr)
if hasattr(prop, 'mapper'):
cls = prop.mapper.class_
if prop.uselist:
# Sequence of objects
value = [self[attr].children[0].objectify(obj)
for obj in dict_[attr]]
else:
# Single object
value = self[attr].objectify(dict_[attr])
else:
value = dict_[attr]
if value is colander.null:
# `colander.null` is never an appropriate
# value to be placed on an SQLAlchemy object
# so we translate it into `None`.
value = None
setattr(context, attr, value)
else:
# try to process association proxy field
desc = mapper.all_orm_descriptors.get(attr)
if desc and desc.extension_type == ASSOCIATION_PROXY:
value = dict_[attr]
if value is colander.null:
# `colander.null` is never an appropriate
# value to be placed on an SQLAlchemy object
# so we translate it into `None`.
value = None
setattr(context, attr, value)
else:
# Ignore attributes if they are not mapped
log.debug(
'SQLAlchemySchemaNode.objectify: %s not found on '
'%s. This property has been ignored.',
attr, self
)
continue
return context
class Form(object):
"""
Base class for all forms.
"""
def __init__(self, fields=None, schema=None, request=None, readonly=False, readonly_fields=[],
model_instance=None, model_class=None, labels={}, renderers={}, widgets={},
action_url=None, cancel_url=None):
self.fields = fields
self.schema = schema
self.request = request
self.readonly = readonly
self.readonly_fields = set(readonly_fields or [])
self.model_instance = model_instance
self.model_class = model_class
if self.model_instance and not self.model_class:
self.model_class = type(self.model_instance)
if self.model_class and self.fields is None:
self.fields = self.make_fields()
self.labels = labels or {}
self.renderers = renderers or {}
self.widgets = widgets or {}
self.action_url = action_url
self.cancel_url = cancel_url
def make_fields(self):
"""
Return a default list of fields, based on :attr:`model_class`.
"""
if not self.model_class:
raise ValueError("Must define model_class to use make_fields()")
mapper = orm.class_mapper(self.model_class)
# first add primary column fields
fields = [prop.key for prop in mapper.iterate_properties
if not prop.key.startswith('_')
and prop.key != 'versions']
# then add association proxy fields
for key, desc in sa.inspect(self.model_class).all_orm_descriptors.items():
if desc.extension_type == ASSOCIATION_PROXY:
fields.append(key)
return fields
def remove_field(self, key):
if key in self.fields:
self.fields.remove(key)
def make_schema(self):
if not self.model_class:
# TODO
raise NotImplementedError
if not self.schema:
mapper = orm.class_mapper(self.model_class)
# first filter our "full" field list so we ignore certain ones. in
# particular we don't want readonly fields in the schema, or any
# which appear to be "private"
includes = [f for f in self.fields
if f not in self.readonly_fields
and not f.startswith('_')
and f != 'versions']
# make schema - only include *property* fields at this point
schema = CustomSchemaNode(self.model_class,
includes=[p.key for p in mapper.iterate_properties
if p.key in includes])
# for now, must manually add any "extra" fields? this includes all
# association proxy fields, not sure how other fields will behave
for field in includes:
if field not in schema:
schema.add(colander.SchemaNode(colander.String(), name=field))
# apply any label overrides
for key, label in self.labels.items():
if key in schema:
schema[key].title = label
# apply any widget overrides
for key, widget in self.widgets.items():
if key in schema:
schema[key].widget = widget
self.schema = schema
return self.schema
def set_label(self, key, label):
self.labels[key] = label
def get_label(self, key):
return self.labels.get(key, prettify(key))
def set_readonly(self, key, readonly=True):
if readonly:
self.readonly_fields.add(key)
else:
if key in self.readonly_fields:
self.readonly_fields.remove(key)
def set_type(self, key, type_):
if type_ == 'codeblock':
self.set_renderer(key, self.render_codeblock)
self.set_widget(key, dfwidget.TextAreaWidget(cols=80, rows=8))
def set_renderer(self, key, renderer):
self.renderers[key] = renderer
def set_widget(self, key, widget):
self.widgets[key] = widget
def set_validator(self, key, validator):
schema = self.make_schema()
schema[key].validator = validator
def render(self, template=None, **kwargs):
if not template:
if self.readonly:
template = '/forms2/form_readonly.mako'
else:
template = '/forms2/form.mako'
context = kwargs
context['form'] = self
return render(template, context)
def make_deform_form(self):
if not hasattr(self, 'deform_form'):
schema = self.make_schema()
# get initial form values from model instance
kwargs = {}
if self.model_instance:
kwargs['appstruct'] = schema.dictify(self.model_instance)
# create form
form = deform.Form(schema, **kwargs)
# set readonly widget where applicable
for field in self.readonly_fields:
if field in form:
form[field].widget = ReadonlyWidget()
self.deform_form = form
return self.deform_form
def render_deform(self, dform=None, template='/forms2/deform.mako', **kwargs):
if dform is None:
dform = self.make_deform_form()
# TODO: would perhaps be nice to leverage deform's default rendering
# someday..? i.e. using Chameleon *.pt templates
# return form.render()
context = kwargs
context['form'] = self
context['dform'] = dform
context['request'] = self.request
context['readonly_fields'] = self.readonly_fields
context['render_field_readonly'] = self.render_field_readonly
return render('/forms2/deform.mako', context)
def render_field_readonly(self, field_name, **kwargs):
label = HTML.tag('label', self.get_label(field_name), for_=field_name)
field = self.render_field_value(field_name) or ''
field_div = HTML.tag('div', class_='field', c=field)
return HTML.tag('div', class_='field-wrapper {}'.format(field), c=label + field_div)
def render_field_value(self, field_name):
record = self.model_instance
if self.renderers and field_name in self.renderers:
return self.renderers[field_name](record, field_name)
return self.render_generic(record, field_name)
def render_generic(self, record, field_name):
value = self.obtain_value(record, field_name)
if value is None:
return ""
return six.text_type(value)
def render_codeblock(self, record, field_name):
value = self.obtain_value(record, field_name)
if value is None:
return ""
return HTML.tag('pre', value)
def obtain_value(self, record, field_name):
try:
return record[field_name]
except TypeError:
return getattr(record, field_name)
def validate(self, *args, **kwargs):
form = self.make_deform_form()
return form.validate(*args, **kwargs)
class ReadonlyWidget(dfwidget.HiddenWidget):
readonly = True
def serialize(self, field, cstruct, **kw):
if cstruct in (colander.null, None):
cstruct = ''
return HTML.tag('span', cstruct) + tags.hidden(field.name, value=cstruct, id=field.oid)