I have to change an already existing StaticBlock to a StructBlock:
class SomeBlock(blocks.StaticBlock):
pass
class Meta:
...
to:
class SomeBlock(blocks.StructBlock):
...
class Meta:
...
However if the wagtail page has already SomeBlock configured in it, I receive the error:
NoneType is not iterable
Since I don't have anything inside the StaticBlock. I need to write a custom data migration for this.
Based on Schema Operations listed, I couldn't find a way to change the actual block type. How do I approach this?
StructBlocks and StaticBlocks live inside StreamFields so you need a Wagtail-specific method for converting blocks within a StreamField. Please see https://wagtail.org/blog/google-summer-of-code-toolkit-for-streamfield-data-migrations-in-wagtail/ for a discussion of the issue. Then you can use the project described https://github.com/wagtail/wagtail-streamfield-migration-toolkit Or, if you want to try out Wagtail 4.2rc1, you can try the built in migration helpers: https://docs.wagtail.org/en/latest/advanced_topics/streamfield_migrations.html#streamfield-data-migrations
Related
I am working on some Django/Python code.
Basically, the backend of my code gets sent a dict of parameters named 'p'. These values all come off Django models.
When I tried to override them as such:
p['age']=25
I got a 'model error'. Yet, if I write:
p.age=25
it works fine.
My suspicion is that, internally, choice #1 tries to set a new value to an instance of a class created by Django that objects to being overridden, but internally Python3 simply replaces the Django instance with a "new" attribute of the same name ('age'), without regard for the prior origin, type, or class of what Django created.
All of this is in a RESTful framework, and actually in test code. So even if I am right I don't believe it changes anything for me in reality.
But can anyone explain why one type of assignment to an existing dict works, and the other fails?
p is a class, not a dict. Django built it that way.
But, as such, one approach (p.age) lets you change an attribute of the object in the class.
I have created custom Django model-field subclasses based on CharField but which use to_python() to ensure that the model objects returned have more complex objects (some are lists, some are dicts with a specific format, etc.) -- I'm using MySQL so some of the PostGreSql field types are not available.
All is working great, but Pylint believes that all values in these fields will be strings and thus I get a lot of "unsupported-membership-test" and "unsubscriptable-object" warnings on code that uses these models. I can disable these individually, but I would prefer to let Pylint know that these models return certain object types. Type hints are not helping, e.g.:
class MealPrefs(models.Model):
user = ...foreign key...
prefs: dict[str, list[str]] = \
custom_fields.DictOfListsExtendsCharField(
default={'breakfast': ['cereal', 'toast'],
'lunch': ['sandwich']},
)
I know that certain built-in Django fields return correct types for Pylint (CharField, IntegerField) and certain other extensions have figured out ways of specifying their type so Pylint is happy (MultiSelectField) but digging into their code, I can't figure out where the "magic" specifying the type returned would be.
(note: this question is not related to the INPUT:type of Django form fields)
Thanks!
I had a look at this out of curiosity, and I think most of the "magic" actually comes for pytest-django.
In the Django source code, e.g. for CharField, there is nothing that could really give a type hinter the notion that this is a string. And since the class inherits only from Field, which is also the parent of other non-string fields, the knowledge needs to be encoded elsewhere.
On the other hand, digging through the source code for pylint-django, though, I found where this most likely happens:
in pylint_django.transforms.fields, several fields are hardcoded in a similar fashion:
_STR_FIELDS = ('CharField', 'SlugField', 'URLField', 'TextField', 'EmailField',
'CommaSeparatedIntegerField', 'FilePathField', 'GenericIPAddressField',
'IPAddressField', 'RegexField', 'SlugField')
Further below, a suspiciously named function apply_type_shim, adds information to the class based on the type of field it is (either 'str', 'int', 'dict', 'list', etc.)
This additional information is passed to inference_tip, which according to the astroid docs, is used to add inference info (emphasis mine):
astroid can be used as more than an AST library, it also offers some
basic support of inference, it can infer what names might mean in a
given context, it can be used to solve attributes in a highly complex
class hierarchy, etc. We call this mechanism generally inference
throughout the project.
astroid is the underlying library used by Pylint to represent Python code, so I'm pretty sure that's how the information gets passed to Pylint. If you follow what happens when you import the plugin, you'll find this interesting bit in pylint_django/.plugin, where it actually imports the transforms, effectively adding the inference tip to the AST node.
I think if you want to achieve the same with your own classes, you could either:
Directly derive from another Django model class that already has the associated type you're looking for.
Create, and register an equivalent pylint plugin, that would also use Astroid to add information to the class so that Pylint know what to do with it.
I thought initially that you use a plugin pylint-django, but maybe you explicitly use prospector that automatically installs pylint-django if it finds Django.
The checker pylint neither its plugin doesn't check the code by use information from Python type annotations (PEP 484). It can parse a code with annotations without understanding them and e.g. not to warn about "unused-import" if a name is used in annotations only. The message unsupported-membership-test is reported in a line with expression something in object_A simply if the class A() doesn't have a method __contains__. Similarly the message unsubscriptable-object is related to method __getitem__.
You can patch pylint-django for your custom fields this way:
Add a function:
def my_apply_type_shim(cls, _context=None): # noqa
if cls.name == 'MyListField':
base_nodes = scoped_nodes.builtin_lookup('list')
elif cls.name == 'MyDictField':
base_nodes = scoped_nodes.builtin_lookup('dict')
else:
return apply_type_shim(cls, _context)
base_nodes = [n for n in base_nodes[1] if not isinstance(n, nodes.ImportFrom)]
return iter([cls] + base_nodes)
into pylint_django/transforms/fields.py
and also replace apply_type_shim by my_apply_type_shim in the same file at this line:
def add_transforms(manager):
manager.register_transform(nodes.ClassDef, inference_tip(my_apply_type_shim), is_model_or_form_field)
This adds base classes list or dict respectively, with their magic methods explained above, to your custom field classes if they are used in a Model or FormView.
Notes:
I thought also about a plugin stub solution that does the same, but the alternative with "prospector" seems so complicated for SO that I prefer to simply patch the source after installation.
Classes Model or FormView are the only classes created by metaclasses, used in Django. It is a great idea to emulate a metaclass by a plugin code and to control the analysis simple attributes. If I remember, MyPy, referenced in some comment here, has also a plugin mypy-django for Django, but only for FormView, because writing annotations for django.db is more complicated than to work with attributes. - I was trying to work on it for one week.
I want to modify the default Django error reporting template TECHNICAL_500_TEXT_TEMPLATE to provide custom error message. Read doc on modifying the filter tried
DEFAULT_EXCEPTION_REPORTER_FILTER = 'path.to.your.CustomExceptionReporterFilter' but it's about filtering data but I would like to override the default template itself.
Tried overriding DEFAULT_EXCEPTION_REPORTER_FILTER and defining custom get_traceback_text and hence passing custom template instead of TECHNICAL_500_TEXT_TEMPLATE in the method.
Any suggestions would be helpful
I started noticing the change in the emails after upgrading from 1.7 to 1.9. I used the approach in the following answer. I basically removed the 'settings' section from the templates, including a few other lines that weren't needed.
Django error email is too long. How do I truncate it?
So I'm working on some unit tests and relational fixtures.
I'm creating a model dynamically like:
$model = CActiveRecord::model('Post');
$post = $model->findByPk(1);
But after that I cannot for some reason get $post->id. I traced the problem to CActiveRecord class:
public function __get($name)
{
if(isset($this->_attributes[$name]))
return $this->_attributes[$name];
...
Where $name = "id". It says that $this->_attributes[$name] does not exist! As a matter of fact _attributes is empty.
My Post class does not define id (or any other properties) as a public property and I don't want to do so either. I just let the AR map it to table columns for me.
What am I missing?
Edit 1
My fixtures are regular Yii fixtures - nothing really special about them.
What differs is the way I load them really. I extended the CDbFixtureManager to be able to specify the order in which they should be loaded by overloading load() method. Only thing of interest that actually fails is that in the fixtures that have foreign keys I use the following:
'comment1' => array('post_id' => $this->getRecord('Post', 'post1')->id);
That's where it fails. getRecord returns the actual Post record (since I know the Post fixture has already been successfully loaded and exists in DB), but on the ->id part I get an exception about that attribute not existing.
If I go into Post model and add public $id; to it, then everything works! But I'm not sure if it's good practice to go about declaring all properties public like that.
If you look at this page carefully:
http://www.yiiframework.com/doc/guide/1.1/en/test.unit
you'll see that they use an array form for retrieving fixtures:
$this->posts['sample1']['id']
There is an alias defined in their fixture array for each record and fixture items aren't loaded as models really ...
Does that help? If not, it would be helpful to see your fixture file :-)
I think I found the root cause of this issue for me. While my FixtureManager was using the testdb DBConnection, the models still used the regular one.
For whatever reason, my debugger was giving me misleading errors like the one described in my original post.
Once I was able to set the DBConnection of all Models in the unit test the puzzle snapped into place and everything is now working smoothly!
I am working on a test project using django-nonrel.
After enabling the admin interface and adding some entities to the database, I added a search_field to the ModelAdmin class. As I tried to search I got the following error:
DatabaseError: Lookup type 'icontains' isn't supported
In order to fix this, I added an index like this:
from models import Empresa
from dbindexer.api import register_index
register_index(Empresa, {'nombre': 'icontains'})
But now I am getting the following error:
First ordering property must be the same as inequality filter property, if specified for this query; received key, expected idxf_nombre_l_icontains
Am I trying to do something that is not supported by django-nonrel and dbindex yet?
Thanks in advance for any help
I have the same problem (on another case), know the cause of it, but currently have no solution.
It is because of GAE's database limitation in which if a query contain an inequality comparison, that is ' < , > , >= ' or something like that, any ordering of any member of the entities (other than the member that use the inequality comparison) must be preceded by an ordering of the member with inequality comparison first.
If we are directly using GAE's database, this limitation can easily be overcome by first set the order by the member that use the inequality first, than sort with whatever you want to sort.
Unfortunately, the django-nonrel and djangoappengine's database wrapper seems to be unable to do that (I've tried the order by first technique using django model, still error, maybe it's just me), not to mention the use of dbindexer as the wrapper of djangoappengine.db which itself is a wrapper of GAE's database......
Bottomline, debugging can be a hell for this mess. You may want to use GAE datastore directly just for this case, or wait for djangoappengine team to come up with better alternative.
I kind of fixed it by changing the ordering property in the ModelAdmin subclass:
class EmpresaAdmin(admin.ModelAdmin):
search_fields = ('nombre',)
#order by the atribute autogenerated by dbindex
ordering = ('idxf_nombre_l_icontains',)
Does anyone know a better way to fix this?