I want to use exclude in peewee just like Django, the code like this
# Feature is a model
qs = Feature.exclude(id=1)
the exception is
AttributeError: type object 'Feature' has no attribute 'exclude'
Then i try this
qs = Feature.filter(~Feature.get_by_id(1))
the exception
TypeError: bad operand type for unary ~: 'Feature'
You can:
qs = Feature.select().where(Feature.id != 1)
Or
qs = Feature.select().where(~(Feature.id == 1))
Note that get_by_id() is not a chainable method. It simply fetches an object (the equivalent of Django's .get()).
Related
I am using wagtail ModelAdmin for some of my non page models and want to add some custom validation.
This is some of the code.
class EditPlanningView(EditView):
def publish_url(self):
return self.url_helper.get_action_url('publish', self.pk_quoted)
def unpublish_url(self):
return self.url_helper.get_action_url('unpublish', self.pk_quoted)
def post(self, request, *args, **kwargs):
form = self.get_form()
if form.is_valid():
instance = form.save(commit=False)
if bool(request.POST.get('action-publish')):
try:
instance.publish(commit=True)
except PublishWithoutMeetingError as e:
form.add_error(
'planning_meeting',
e
)
return self.form_invalid(form)
When validation fails the invalid form is returned, but the error I added is not bound to the field. In stead a 'general error message' appears at the top.
Can someone help me out?
Cheers,
Robert
I think the error is in the following lines.
form.add_error(
'planning_meeting',
e
)
Actually can't say anything without knowing about PublishWithoutMeetingError, the type of e. Better to replace e with a string. And make sure the post method is not throwing any exceptions. Other than that, what you have done is correct. Read the following to also to check if you have missed any point.
Long Answer
There are two ways that you can achieve showing an error messages in forms.
Overriding the Form
Overriding the EditView
In both of these cases, you are going to use a method called add_error. That method takes 2 argument, field and error. From these two, error is the most important argument. The field simply state the field of the form that this error applies to. This can be None.
The error argument can be multiple types.
The error argument can be an instance of str. Then wagtail will assign the given error to the given field.
The error argument can be an instance of list of str. Then wagtail will assign the given list of errors to the given field.
The error argument can be an instance of dict with str keys and str or list of str values. In this case field should be None. The keys will be used as the fields for the errors given by values.
The error argument can be an instance of ValidationError exception. You can create a ValidationError using a str, list, or dict, which represent the above three cases.
Overriding the Form
In the form clean method need to be overridden in order to find errors.
from wagtail.admin.forms.models import WagtailAdminModelForm
class ExtraForm(WagtailAdminModelForm):
def clean(self):
cleaned_data = super().clean() # Get the already cleaned data. Same as self.cleaned_data in this case. But this way is better.
title = cleaned_data.get('title') # Get the cleaned title
if title is None: # Title is never None here, but still..
return cleaned_data
title = title.strip() # Do some formatting if needed
if title.startswith('A'): # Validation
self.add_error('title', 'Title cannot start with A') # Validation error
else:
cleaned_data['title'] = title # Use the formatted title
return cleaned_data
class MyModel(models.Model):
id = models.AutoField(primary_key=True)
title = models.CharField(max_length=500, default='', blank=False)
# Or any other fields you have
base_form_class = ExtraForm # Tell wagtail to use ExtraForm instead of the default one
Overriding the EditView
This way is same as the way that you have mentioned in the question. You need to override post method. You need to check if the form associated with the EditView is valid or invalid and return the appropriate form.
To check validity, is_valid method of the form is used by default. That method will clean the form and check if there are errors added to the form.
If form is valid, you need to return self.valid_form and self.invalid_form otherwise.
Unlike overriding the Form, you can access the request here.
class MyEditView(EditView):
def post(self, request, *args, **kwargs):
form = self.get_form() # Get the form associated with this edit view
if form.is_valid(): # Check if the form pass the default checks
my_field = request.POST.get('my_field') # You can access the request
title = form.cleaned_data.get('title') # You can access the form data
if title != my_field: # Validation
form.add_error('title', 'Title must match my_field') # Validation error
return self.form_invalid(form) # Return invalid form if there are validation errors
return self.form_valid(form) # Return the valid form if there are no validation errors
else:
return self.form_invalid(form) # Return invalid form if default check failed
class MyModelAdmin(ModelAdmin):
model = MyModel
menu_label = 'My Model'
list_display = ('id', 'title')
search_fields = (
'title',
)
edit_view_class = MyEditView # Tell wagtail to use MyEditView instead of the default one.
Normally we do queries like this
#MyModel.query_method(path='mymodels', name='mymodel.list')
def MyModelList(self, query):
return query
But how can I perform custom queries on Endpoints model and how do I pass custom parameters other than "id, limit, order.." etc
For eg :
return query.filter(Student.name == somename )
How can I supply "somename" to the endpoint ?
If the property you want to filter by is part of your Model you can just add 'name' as query_field
#MyModel.query_method(path='mymodels',
name='mymodel.list',
query_fields=('name',))
This will automatically apply an equality filter (MyModel.name == name) if name is supplied in the API request.
If you need more custom queries you can work with EndpointsAliasProperty on your model and directly access the model's _endpoints_query_info._filters
Example for doing an inequality filter with a date:
class MyModel(EndpointsModel):
...
updated = EndpointsDateTimeProperty(auto_now=True)
...
def MinDateSet(self, value):
if value is not None:
self._endpoints_query_info._filters.add(MyModel.updated >= value)
#EndpointsAliasProperty(setter=MinDateSet,
property_type=message_types.DateTimeField)
def minDate(self):
"""
minDate is only used as parameter in query_methods
so there should never be a reason to actually retrieve the value
"""
return None
#MyModel.query_method(path='mymodels',
name='mymodel.list',
query_fields=('minDate',))
This will automatically apply the MyModel.updated >= minDate filter if minDate is supplied in the API request.
I was just trying neo4django's very own example, namely
from neo4django.db import models
class Person(models.NodeModel):
name = models.StringProperty()
age = models.IntegerProperty()
friends = models.Relationship('self',rel_type='friends_with')
However, when running python manage.py syncdb I get the following error:
AttributeError: type object 'Model' has no attribute '__metaclass__'
Any ideas?
(I would use label "neo4django" here in Stackoverflow, but it does not let me create a new label yet).
See https://github.com/scholrly/neo4django/issues/143- we won't support Django 1.5+ until the next release!
I am trying to save Event. But it does not work. Will you please help? thanks alot
query = []
query = Identity.all().filter('name =', 'k').fetch(1)
if query:
for q in query:
event_id = q.key().id()
Event(description=description, identity=event_id)
Event Model
class Event(search.SearchableModel):
description = db.TextProperty(required=True)
identity = db.ReferenceProperty(Identity)
Getting error message >
if value is not None and not value.has_key():
AttributeError: 'long' object has no attribute 'has_key'
Your assigning the id of the object into a ReferenceProeprty, this is wrong.
Your code should look something like this:
query = Identity.all().filter('name =', 'k').get()
if query:
Event(description=description, identity=q)
Also instead of having your own name attribute you use use the buitin key_name attribute that each Model has, its faster and cheaper.
query = Identity.get_by_key_name(k)
if query:
Event(description=description, identity=q)
I just have a hunch about this. But if feels like I'm doing it the wrong way. What I want to do is to have a db.StringProperty() as a unique identifier. I have a simple db.Model, with property name and file. If I add another entry with the same "name" as one already in the db.Model I want to update this.
As of know I look it up with:
template = Templates.all().filter('name = ', name)
Check if it's one entry already:
if template.count() > 0:
Then add it or update it. But from what I've read .count() is every expensive in CPU usage.
Is there away to set the "name" property to be unique and the datastore will automatic update it or another better way to do this?
..fredrik
You can't make a property unique in the App Engine datastore. What you can do instead is to specify a key name for your model, which is guaranteed to be unique - see the docs for details.
I was having the same problem and came up with the following answer as the simplest one :
class Car(db.Model):
name = db.StringProperty(required=True)
def __init__(self,*args, **kwargs):
super(Car, self).__init__(*args, **kwargs)
loadingAnExistingCar = ("key" in kwargs.keys() or "key_name" in kwargs.keys())
if not loadingAnExistingCar:
self.__makeSureTheCarsNameIsUnique(kwargs['name'])
def __makeSureTheCarsNameIsUnique(self, name):
existingCarWithTheSameName = Car.GetByName(name)
if existingCarWithTheSameName:
raise UniqueConstraintValidationException("Car should be unique by name")
#staticmethod
def GetByName(name):
return Car.all().filter("name", name).get()
It's important to not that I first check if we are loading an existing entity first.
For the complete solution : http://nicholaslemay.blogspot.com/2010/07/app-engine-unique-constraint.html
You can just try to get your entity and edit it, and if not found create a new one:
template = Templates.gql('WHERE name = :1', name)
if template is None:
template = Templates()
# do your thing to set the entity's properties
template.put()
That way it will insert a new entry when it wasn't found, and if it was found it will update the existing entry with the changes you made (see documentation here).
An alternative solution is to create a model to store the unique values, and store it transationally using a combination of Model.property_name.value as key. Only if that value is created you save your actual model. This solution is described (with code) here:
http://squeeville.com/2009/01/30/add-a-unique-constraint-to-google-app-engine/
I agree with Nick. But, if you do ever want to check for model/entity existence based on a property, the get() method is handy:
template = Templates.all().filter('name = ', name).get()
if template is None:
# doesn't exist
else:
# exists
I wrote some code to do this. The idea for it is to be pretty easy to use. So you can do this:
if register_property_value('User', 'username', 'sexy_bbw_vixen'):
return 'Successfully registered sexy_bbw_vixen as your username!'
else:
return 'The username sexy_bbw_vixen is already in use.'
This is the code. There are a lot of comments, but its actually only a few lines:
# This entity type is a registry. It doesn't hold any data, but
# each entity is keyed to an Entity_type-Property_name-Property-value
# this allows for a transaction to 'register' a property value. It returns
# 'False' if the property value is already in use, and thus cannot be used
# again. Or 'True' if the property value was not in use and was successfully
# 'registered'
class M_Property_Value_Register(db.Expando):
pass
# This is the transaction. It returns 'False' if the value is already
# in use, or 'True' if the property value was successfully registered.
def _register_property_value_txn(in_key_name):
entity = M_Property_Value_Register.get_by_key_name(in_key_name)
if entity is not None:
return False
entity = M_Property_Value_Register(key_name=in_key_name)
entity.put()
return True
# This is the function that is called by your code, it constructs a key value
# from your Model-Property-Property-value trio and then runs a transaction
# that attempts to register the new property value. It returns 'True' if the
# value was successfully registered. Or 'False' if the value was already in use.
def register_property_value(model_name, property_name, property_value):
key_name = model_name + '_' + property_name + '_' + property_value
return db.run_in_transaction(_register_property_value_txn, key_name )