def index(request):
expiring_list = probe.objects.filter("isExpired=True")
output = ', '.join([p.serial for p in expiring_list])
return HttpResponse(output)
isExpired is a Boolean function. How should I modify the filter so that the filter does not raise a ValueError?
You are making the query in a wrong format.
Your query should be of the form:
expiring_list = probe.objects.filter(isExpired = True)
This was the query you needed to make in case isExpired was your model field. But since you say its a function, assuming that function is inside the class you need to get all the objects in the following way:
expiring_list = []
objects = probe.objects.all()
for obj in objects:
if obj.isExpired() == True:
expiring_list.append(obj)
The expiring_list will now contain all the objects of the model probe where isExpired function returns True
I think isExpired is not a field in your models, as reference to your previous question Refresh a field from another table [Django]
I think exp_date is the field which you are looking for.
Try this:
import datetime
def index(request):
expiring_list = probe.objects.filter(exp_date__lt=datetime.date.today())
output = ', '.join([p.serial for p in expiring_list])
return HttpResponse(output)
Related
I need to sort the values for each field alphabetically when they get returned by the API. It seems marshmallow's pre_dump method is the way to pre-process the data before serializing, but I haven't been able to figure this out. I've read the docs multiple times and Googled but haven't found the answer.
class UserSettingsSchema(UserSchema):
class Meta:
fields = (
"id",
"injuries",
"channel_levels",
"movement_levels",
"equipments",
"goals",
"genres"
)
#pre_dump
def pre_dump_hook(): # what do I pass in here?
# alphabetize field values, eg, all the genres will be sorted
equipments = fields.Nested(EquipmentSchema, many=True)
goals = fields.Nested(GoalSchemaBrief, many=True)
genres = fields.Nested(GenreSchemaBrief, many=True)
The answer given by PoP does not address the fact that I needed the values sorted. This is how I did it:
#post_load
def post_load_hook(self, item):
item['genres'] = sorted(item['genres'])
return item
As mentioned in the docs:
By default, receives a single object at a time, regardless of whether many=True is passed to the Schema.
Here's an example:
from marshmallow import *
class MySchema(Schema):
name = fields.String()
#pre_dump
def pre_dump_hook(self, instance):
instance['name'] = 'Hello %s' % instance['name']
Now you can do:
schema = MySchema()
schema.dump({'name': 'Bill'})
>>> MarshalResult(data={'name': 'Hello Bill'}, errors={})
I'm doing a simple filter -
filters.py
class TblserversFilter(django_filters.FilterSet):
name = django_filters.CharFilter(name="servername", lookup_type="exact")
class Meta:
model = Tblservers
fields = ['servername']
What I would like to do, if possible, is to have two lookup_types associated with the field. Specifically I want exact AND contains and then somehow replace the operator depending on the filter.
name=serverabc would be an exact search and name~abc will be a fuzzy search.
You could do a method_filter and then prefix your filter queries with different symbols for exact and icontains and other filters that you want at the client side.
Since code is better than a thousand words:
exact_prefix = '#'
icontains_prefix = '~'
class TblserversFilter(django_filters.FilterSet):
name = django_filters.MethodFilter(
action=name_filter)
def name_filter(self, value):
if value:
value_prefix = value[0]
if value_prefix == exact_prefix:
return self.filter(name=value)
elif value_prefix == icontains_prefix:
return self.filter(name__icontains=value)
# this can continue for all the types of filters you want
else:
return self.filter(name=value)
else:
return self.filter(name=value)
class Meta:
model = Tblservers
fields = ['servername']
EDIT:
In django-filter 1.0 MethodFilter was replaced with Filter's method argument. So solution rewritten for v1.0 would be following (not tested):
exact_prefix = '#'
icontains_prefix = '~'
class TblserversFilter(django_filters.FilterSet):
name = django_filters.CharFilter(
method='name_filter')
def name_filter(self, qs, name, value):
if value:
value_prefix = value[0]
if value_prefix == exact_prefix:
return qs.filter(name=value)
elif value_prefix == icontains_prefix:
return qs.filter(name__icontains=value)
# this can continue for all the types of filters you want
else:
return qs.filter(name=value)
else:
return qs.filter(name=value)
class Meta:
model = Tblservers
fields = ['servername']
First my apologies for the shameless library self-plug.
At some point I was trying to do something similar in django-filters however the solution was much more complex then anticipated. I ended up creating my own library for doing filtering in Django which natively supports the exact functionality you are looking for - django-url-filter. Its API is very similar to django-filters:
from django import forms
from url_filter.filter import Filter
from url_filter.filtersets import ModelFilterSet
class TblserversFilter(FilterSet):
name = Filter(form_field=forms.CharField(max_length=15), lookups=['exact', 'contains'])
class Meta(object):
model = Tblservers
fields = ['name', 'servername']
Note that the URL will look a bit different though:
?name=foo # exact
?name__exact=foo
?name__contains=foo
Also you will need to manually call the filter set in order to filter the queryset:
fs = TblserversFilter(data=query, queryset=...)
filtered_qs = fs.filter()
Syntax of the URL parameters is very similar to Django ORM.
You can look at the docs for more examples. Hopefully it might be of use.
I've got the following view:
def search_events(request):
term = request.GET.get('term', '')
adminDivision = request.GET.get('adminDivision', '')
events = Event.objects.filter(event_name__icontains=term, city__admin1=adminDivision)
data= serializers.serialize('json', events);
return HttpResponse(data, content_type='application/json')
It can receive 2 parameters from the request, term and adminDivision, and then it makes a search on the DB.
The way it works now is that when one of them is empty, term or adminDivision, then I get no results, as all the objects has some value for those fields.
What I want is, if one or even both filters are empty, then don't apply that filter.
Example,
if I've got these objects:
[event_name='foo', adminDivision='1']
[event_name='bar', adminDivision='2']
[event_name='foo bar', adminDivision='3']
With term=foo (no value for adminDivision) at the moment, I'am getting no results, but I would want it to return the first and the third.
With both values empty, I am also getting no results, and I'd like to have all them.
Is there an elegant way to achieve this?
Thank you!
You are not getting results because you are performing an AND query in your filter. Try like this:
def search_events(request):
term = request.GET.get('term', '')
adminDivision = request.GET.get('adminDivision', '')
events = Event.objects.all()
if term:
events = events.filter(event_name__icontains=term)
if adminDivision:
events = events.filter(city__admin1=adminDivision)
data= serializers.serialize('json', events);
return HttpResponse(data, content_type='application/json')
Or:
from django.db.models import Q
...
events = Event.objects.filter(Q(event_name__icontains=term)|Q(city__admin1=adminDivision))
...
I am trying to iterate over form results and I can't help but think that I am re-inventing the wheel here.
filterlist = []
if request.POST:
form = FilterForm(request.POST)
if form.is_valid():
for key, value in form.cleaned_data.iteritems():
filterlist.append(key)
filterlist.append(value)
This works, but seems very awkward and creates lots of other problems. For example the values come back with u' so I have to use value.encode("utf8") but then if a value is None it throws in error. So now I have to check if it is None, if not then encode. There has to be a better way.
EDIT: What I am trying to do.
I am trying to filter what is shown on a page. The problem I am running into is that if a value is empty (the user don't fill the box because they only want to filter against one object) then I get no results. For example a user wants to search for all books by the author name "Smith" but doesn't want to search against a genre.
results = Books.objects.filter(author=author, genre=genre)
The user would get no results because this is an AND search. But, if a user put in "Smith" for the author and "mystery" for the genre then it works exactly like I want it to, only giving results where both are true.
So, I am trying to eliminate the empty stuff by iterating over the form results. Like I said I am probably re-inventing the wheel here.
In Python 3 use:
for key, value in form.cleaned_data.items():
If the field names are the same in the model and the form, try this:
filter = {}
if request.method == 'POST':
form = FilterForm(request.POST)
if form.is_valid():
for key, value in form.cleaned_data.iteritems():
if value:
filter[key] = value
results = Books.objects.filter(**filter)
Python is one of the few languages having named parameters. You can assemble a dict with the non-empty form fields and pass it to the filter method using the kwargs unpacking operator **.
For example:
kwargs = {"author": "Freud"}
results = Books.objects.filter(**kwargs)
Is the same as:
results = Books.objects.filter(author="Freud")
I think the problem is that by default the Model form is not valid if a form field does not have a value entered by the user, if you don`t require the field every time from the user you need to set the required field to false in the ModelForm class in forms.py as shown in the code below. Remember that the field is set false only in the model form not in the model itself
class myForm(forms.ModelForm):
myfield_id = forms.CharField(required=False)
myfield_foo = forms.CharField(required=False)
myfield_bar = forms.CharField(required=False)
myfield_name = forms.CharField(required=False)
class Meta:
model = myModel
exclude = ('myfield_ex','myfield_file')
fields = ['myfield_id','myfield_foo','myfield_bar','myfield_name',]
After you have the form entered by the user what you need is use the Q object which can be used to create complex queries as described in the manula page here
https://docs.djangoproject.com/en/1.7/topics/db/queries/#complex-lookups-with-q
A simple example code would look like
if form.is_valid():
qgroup = []
for key,value in form.cleaned_data.iteritems():
if value:
q_name = Q(**{"%s"%format(filterKey[key]) : value})
qgroup.append(q_name)
q = None
# can use the reduce as shown here qgroup = reduce(operator.or_, (Q(**{"{0}".format(filterKey[key]): value}) for (key,value) in form.cleaned_data.iteritems()))
for key,value in form.cleaned_data.iteritems():
if value:
q_name = Q(**{"%s"%format(filterKey[key]) : value})
qgroup.append(q_name)
for x in qgroup:
q &= x ### Or use the OR operator or
if q:
resultL = myModel.objects.filter(q).select_related()
The filterKey can look something on the lines of
filterKey = {'myfield_id' : "myfield_id",
'myfield_foo' : "myfield_foo__icontains",
'myfield_bar' : "myfield_bar__relative_field__icontains",
}
I want to create a new type of field for django models that is basically a ListOfStrings. So in your model code you would have the following:
models.py:
from django.db import models
class ListOfStringsField(???):
???
class myDjangoModelClass():
myName = models.CharField(max_length=64)
myFriends = ListOfStringsField() #
other.py:
myclass = myDjangoModelClass()
myclass.myName = "bob"
myclass.myFriends = ["me", "myself", "and I"]
myclass.save()
id = myclass.id
loadedmyclass = myDjangoModelClass.objects.filter(id__exact=id)
myFriendsList = loadedclass.myFriends
# myFriendsList is a list and should equal ["me", "myself", "and I"]
How would you go about writing this field type, with the following stipulations?
We don't want to do create a field which just crams all the strings together and separates them with a token in one field like this. It is a good solution in some cases, but we want to keep the string data normalized so tools other than django can query the data.
The field should automatically create any secondary tables needed to store the string data.
The secondary table should ideally have only one copy of each unique string. This is optional, but would be nice to have.
Looking in the Django code it looks like I would want to do something similar to what ForeignKey is doing, but the documentation is sparse.
This leads to the following questions:
Can this be done?
Has it been done (and if so where)?
Is there any documentation on Django about how to extend and override their model classes, specifically their relationship classes? I have not seen a lot of documentation on that aspect of their code, but there is this.
This is comes from this question.
There's some very good documentation on creating custom fields here.
However, I think you're overthinking this. It sounds like you actually just want a standard foreign key, but with the additional ability to retrieve all the elements as a single list. So the easiest thing would be to just use a ForeignKey, and define a get_myfield_as_list method on the model:
class Friends(model.Model):
name = models.CharField(max_length=100)
my_items = models.ForeignKey(MyModel)
class MyModel(models.Model):
...
def get_my_friends_as_list(self):
return ', '.join(self.friends_set.values_list('name', flat=True))
Now calling get_my_friends_as_list() on an instance of MyModel will return you a list of strings, as required.
What you have described sounds to me really similar to the tags.
So, why not using django tagging?
It works like a charm, you can install it independently from your application and its API is quite easy to use.
I also think you're going about this the wrong way. Trying to make a Django field create an ancillary database table is almost certainly the wrong approach. It would be very difficult to do, and would likely confuse third party developers if you are trying to make your solution generally useful.
If you're trying to store a denormalized blob of data in a single column, I'd take an approach similar to the one you linked to, serializing the Python data structure and storing it in a TextField. If you want tools other than Django to be able to operate on the data then you can serialize to JSON (or some other format that has wide language support):
from django.db import models
from django.utils import simplejson
class JSONDataField(models.TextField):
__metaclass__ = models.SubfieldBase
def to_python(self, value):
if value is None:
return None
if not isinstance(value, basestring):
return value
return simplejson.loads(value)
def get_db_prep_save(self, value):
if value is None:
return None
return simplejson.dumps(value)
If you just want a django Manager-like descriptor that lets you operate on a list of strings associated with a model then you can manually create a join table and use a descriptor to manage the relationship. It's not exactly what you need, but this code should get you started.
Thanks for all those that answered. Even if I didn't use your answer directly the examples and links got me going in the right direction.
I am not sure if this is production ready, but it appears to be working in all my tests so far.
class ListValueDescriptor(object):
def __init__(self, lvd_parent, lvd_model_name, lvd_value_type, lvd_unique, **kwargs):
"""
This descriptor object acts like a django field, but it will accept
a list of values, instead a single value.
For example:
# define our model
class Person(models.Model):
name = models.CharField(max_length=120)
friends = ListValueDescriptor("Person", "Friend", "CharField", True, max_length=120)
# Later in the code we can do this
p = Person("John")
p.save() # we have to have an id
p.friends = ["Jerry", "Jimmy", "Jamail"]
...
p = Person.objects.get(name="John")
friends = p.friends
# and now friends is a list.
lvd_parent - The name of our parent class
lvd_model_name - The name of our new model
lvd_value_type - The value type of the value in our new model
This has to be the name of one of the valid django
model field types such as 'CharField', 'FloatField',
or a valid custom field name.
lvd_unique - Set this to true if you want the values in the list to
be unique in the table they are stored in. For
example if you are storing a list of strings and
the strings are always "foo", "bar", and "baz", your
data table would only have those three strings listed in
it in the database.
kwargs - These are passed to the value field.
"""
self.related_set_name = lvd_model_name.lower() + "_set"
self.model_name = lvd_model_name
self.parent = lvd_parent
self.unique = lvd_unique
# only set this to true if they have not already set it.
# this helps speed up the searchs when unique is true.
kwargs['db_index'] = kwargs.get('db_index', True)
filter = ["lvd_parent", "lvd_model_name", "lvd_value_type", "lvd_unique"]
evalStr = """class %s (models.Model):\n""" % (self.model_name)
evalStr += """ value = models.%s(""" % (lvd_value_type)
evalStr += self._params_from_kwargs(filter, **kwargs)
evalStr += ")\n"
if self.unique:
evalStr += """ parent = models.ManyToManyField('%s')\n""" % (self.parent)
else:
evalStr += """ parent = models.ForeignKey('%s')\n""" % (self.parent)
evalStr += "\n"
evalStr += """self.innerClass = %s\n""" % (self.model_name)
print evalStr
exec (evalStr) # build the inner class
def __get__(self, instance, owner):
value_set = instance.__getattribute__(self.related_set_name)
l = []
for x in value_set.all():
l.append(x.value)
return l
def __set__(self, instance, values):
value_set = instance.__getattribute__(self.related_set_name)
for x in values:
value_set.add(self._get_or_create_value(x))
def __delete__(self, instance):
pass # I should probably try and do something here.
def _get_or_create_value(self, x):
if self.unique:
# Try and find an existing value
try:
return self.innerClass.objects.get(value=x)
except django.core.exceptions.ObjectDoesNotExist:
pass
v = self.innerClass(value=x)
v.save() # we have to save to create the id.
return v
def _params_from_kwargs(self, filter, **kwargs):
"""Given a dictionary of arguments, build a string which
represents it as a parameter list, and filter out any
keywords in filter."""
params = ""
for key in kwargs:
if key not in filter:
value = kwargs[key]
params += "%s=%s, " % (key, value.__repr__())
return params[:-2] # chop off the last ', '
class Person(models.Model):
name = models.CharField(max_length=120)
friends = ListValueDescriptor("Person", "Friend", "CharField", True, max_length=120)
Ultimately I think this would still be better if it were pushed deeper into the django code and worked more like the ManyToManyField or the ForeignKey.
I think what you want is a custom model field.