I have a LinkColum like this:
artist = tables.LinkColumn('artist_detail', args=[A('artist')],
Unfortunately, there are artists which have special characters like a slash in it and are breaking the Django-URL-system.
Reverse for 'artist_detail' with arguments '('Paul Ray Featuring 33 1/3',)' not found. 1 pattern(s) tried: ['artists\\/(?P<artist>[^/]+)$']
I tried to encapsulate A('artist') with django.utils.http.urlencode() but that's not working unfortunately.
Is there a way to solve this issue?
According to the docs you should be using a normal column and using the linkify parameter.
artist = tables.Column(linkify=("artist_detail", (tables.A("artist.pk"), )))
django-tables2 is just relaying these to django's django.urls.reverse. There is no url matching the value you've passed, so you would have to adjust the value you pass.
One way to achieve this is to add a method to your model providing the urlencoded version of the name, and specify that method in the accessor.
Alternatively you can implement a get_absolute_url method on your model and do the urlencodeing in there. You can then use
artist = tables.Column(linkify=true)
I prefer the latter.
Related
right now I have a view to show info about some tickets and I'm trying to add a functionality to filter those tickets.
Say I will have 4 filters:
Date
Owner
Category
Status
Category Status
I want to give the option to use some of those filters, all or none, the thing is I'm kinda lost in how can I make it work in the urls. So far I found that you can add some optional arguments but they appear in some sort of succession like:
/May/Jack/Gas/Accepted
But if I only select 2 filters like /Jack/Accepted/ it grabs the filters incorrectly.
Is there a way I can achieve this? Or some other method I can use instead of this. Ty
Don't try and do this with URL arguments. Instead, use querystring arguments. The URL should be in the form:
my_path/?date=May&owner=Jack&category=Gas&status=accepted
and the URL pattern is just:
url(r'^my_path/$', views.my_view, 'my_url'),
and in the view you can access request.GET['date'] etc.
I've followed django tutorial and arrived at tutorial05.
I tried to not show empty poll as tutorial says, so I added filter condition like this:
class IndexView(generic.ListView):
...
def get_queryset(self):
return Question.objects.filter(
pub_date__lte=timezone.now(),
choice__isnull=False
).order_by('-pub_date')[:5]
But this returned two objects which are exactly same.
I think choice__isnull=False caused the problem, but not sure.
choice__isnull causes the problem. It leads to join with choice table (to weed out questions without choices), that is something like this:
SELECT question.*
FROM question
JOIN choice
ON question.id = choice.question_id
WHERE question.pub_date < NOW()
You can inspect query attribute of QuerySet to be sure. So if you have one question with two choices, you will get that question two times. You need to use distinct() method in this case: queryset.distinct().
Just use .distinct() at the end of your ORM.
A little late to the party, but I figured it could help others looking up the same issue.
Instead of using choice__isnull=False with the filter() method, use it with exclude() instead to exclude out any questions without any choices. So your code would look something like this:
...
def get_queryset(self):
return Question.objects.filter(pub_date__lte=timezone.now()).exclude(choice__isnull=True).order_by('-pub_date')[:5]
By doing it this way, it will return only one instance of the question. Be sure to use choice_isnull=True though.
Because you created two objects with same properties. If you want to ensure uniqueness, you should add validation in clean and add unique index on identifier field too.
Besides filter returns all the objects that match the criteria, if you are expecting only one item to be returned, you should use get instead. get would raise exception if less or more than 1 item is found.
Is there a negation filter available by default. The idea is that you can do the following in the django ORM:
model.objects.filter(field!=value)
How can I do that in tastypie if that is even possible. I tried:
someapi.com/resource/pk/?field__not=value
someapi.com/resource/pk/?field__!=value
someapi.com/resource/pk/?field!=value
And all of them given me errors.
Unfortunately there's not.
The problem is that Tastypie's ModelResource class uses the filter() method of the QuerySet only, i.e. it does not use exclude() which should be used for negative filters. There is no filter() field lookup that would mean negation though. The valid lookups are (after this SO post):
exact
iexact
contains
icontains
in
gt
gte
lt
lte
startswith
istartswith
endswith
iendswith
range
year
month
day
week_day
isnull
search
regex
iregex
However it shouldn't be so hard to implement the support for something like "__not_eq". All you need to do is to modify the apply_filters() method and separate filters with "__not_eq" from the rest. Then you should pass the first group to exclude() and the rest to filter().
Something like:
def apply_filters(self, request, applicable_filters):
"""
An ORM-specific implementation of ``apply_filters``.
The default simply applies the ``applicable_filters`` as ``**kwargs``,
but should make it possible to do more advanced things.
"""
positive_filters = {}
negative_filters = {}
for lookup in applicable_filters.keys():
if lookup.endswith( '__not_eq' ):
negative_filters[ lookup ] = applicable_filters[ lookup ]
else:
positive_filters[ lookup ] = applicable_filters[ lookup ]
return self.get_object_list(request).filter(**positive_filters).exclude(**negative_filters)
instead of the default:
def apply_filters(self, request, applicable_filters):
"""
An ORM-specific implementation of ``apply_filters``.
The default simply applies the ``applicable_filters`` as ``**kwargs``,
but should make it possible to do more advanced things.
"""
return self.get_object_list(request).filter(**applicable_filters)
should allow for the following syntax:
someapi.com/resource/pk/?field__not_eq=value
I haven't tested it. It could probably be written in more elegant way too, but should get you going :)
Another way to do this without code changes is to use a iregex with inverse matching
http://HOST/api/v1/resource/?format=json&thing__iregex=^((?!notThis).)*$
I've opened a bug for this and provided a simple solution here: https://github.com/toastdriven/django-tastypie/issues/524
It would probably be nicer to add the '!' character at the end of the field name as you've done in your question ...
Note on Gorneau's above answer: seems like this only works if you're not using a MySQL backend. See:
#1139 - Got error 'repetition-operator operand invalid' from regexp
I use exclude() to avoid some values. For example:
Person.filter(name="Tim").exclude(state="Down");
How can I retrieve the last record in a certain queryset?
Django Doc:
latest(field_name=None) returns the latest object in the table, by date, using the field_name provided as the date field.
This example returns the latest Entry in the table, according to the
pub_date field:
Entry.objects.latest('pub_date')
EDIT : You now have to use Entry.objects.latest('pub_date')
You could simply do something like this, using reverse():
queryset.reverse()[0]
Also, beware this warning from the Django documentation:
... note that reverse() should
generally only be called on a QuerySet
which has a defined ordering (e.g.,
when querying against a model which
defines a default ordering, or when
using order_by()). If no such ordering
is defined for a given QuerySet,
calling reverse() on it has no real
effect (the ordering was undefined
prior to calling reverse(), and will
remain undefined afterward).
The simplest way to do it is:
books.objects.all().last()
You also use this to get the first entry like so:
books.objects.all().first()
To get First object:
ModelName.objects.first()
To get last objects:
ModelName.objects.last()
You can use filter
ModelName.objects.filter(name='simple').first()
This works for me.
Django >= 1.6
Added QuerySet methods first() and last() which are convenience methods returning the first or last object matching the filters. Returns None if there are no objects matching.
When the queryset is already exhausted, you may do this to avoid another db hint -
last = queryset[len(queryset) - 1] if queryset else None
Don't use try...except....
Django doesn't throw IndexError in this case.
It throws AssertionError or ProgrammingError(when you run python with -O option)
You can use Model.objects.last() or Model.objects.first().
If no ordering is defined then the queryset is ordered based on the primary key. If you want ordering behaviour queryset then you can refer to the last two points.
If you are thinking to do this, Model.objects.all().last() to retrieve last and Model.objects.all().first() to retrieve first element in a queryset or using filters without a second thought. Then see some caveats below.
The important part to note here is that if you haven't included any ordering in your model the data can be in any order and you will have a random last or first element which was not expected.
Eg. Let's say you have a model named Model1 which has 2 columns id and item_count with 10 rows having id 1 to 10.[There's no ordering defined]
If you fetch Model.objects.all().last() like this, You can get any element from the list of 10 elements. Yes, It is random as there is no default ordering.
So what can be done?
You can define ordering based on any field or fields on your model. It has performance issues as well, Please check that also. Ref: Here
OR you can use order_by while fetching.
Like this: Model.objects.order_by('item_count').last()
If using django 1.6 and up, its much easier now as the new api been introduced -
Model.object.earliest()
It will give latest() with reverse direction.
p.s. - I know its old question, I posting as if going forward someone land on this question, they get to know this new feature and not end up using old method.
In a Django template I had to do something like this to get it to work with a reverse queryset:
thread.forumpost_set.all.last
Hope this helps someone looking around on this topic.
MyModel.objects.order_by('-id')[:1]
If you use ids with your models, this is the way to go to get the latest one from a qs.
obj = Foo.objects.latest('id')
You can try this:
MyModel.objects.order_by('-id')[:1]
The simplest way, without having to worry about the current ordering, is to convert the QuerySet to a list so that you can use Python's normal negative indexing. Like so:
list(User.objects.all())[-1]
Recently i have implemented django-sphinx search on my website.
It is working fine of each separate model.
But now my client requirement has changed.
To implement that functionality i need field name to whom search is made.
suppose my query is:
"select id, name,description from table1"
and search keyword is matched with value in field "name". So i need to return that field also.
Is it possible to get field name or any method provided by django-sphinx which return field name.
Please help me...
As far as I know, this isn't possible. You might look at the contents of _sphinx though.
Well from django-sphinx it might not be possible. But there is a solution -
Make different indexes, each index specifying the field that you need to search.
In your django-sphinx models while searching do this -
search1 = SphinxSearch(index='index1')
search2 = SphinxSearch(index='index2')
...
After getting all the search results, you aggregate them & you have the info of from where they have come.