I making a gender form using Flask-WTF, here is the snippet of my code:
class Gender(enum.Enum):
Male = 'Male'
Female = 'Female'
def __str__(self):
return self.value
gender = [(str(y), y) for y in (Gender)]
class EditStudentForm(Form):
gender = SelectField('Gender', choices=gender)
#app.route('/edit_student')
def edit_student():
student = Student.query.filter_by(id=student_id).first()
student_form = EditStudentForm()
# ... validate on submit
# ....
# ....
return render_template(student=student, student_form=student_form)
That code already works, included I can insert the data to the database.
But, if the current user gender value on database is Female, whenever I refresh the browsers, the form did not get the current value.
In HTML I want it to be like this:
// edit form
<form>
<input type="" value="currentUserValueFromDatabase">
</form>
I try to get current value using this way:
{{ f.render_field(student_form.gender, value=student.gender) }}
But it didn't prepopulate the current value from current user gender.
So what I want is to to display current value on selectfield or prepopulate the selectfield according to the current user value on the database.
Pass student to the EditStudentForm as the obj keyword argument, e.g.:
student_form = EditStudentForm(obj=student_form)
Why? From WTForms docs:
obj – If formdata is empty or not provided, this object is checked for
attributes matching form field names, which will be used for field
values.
When you construct the form when handling a GET request, there is no form data, so it will use the object data.
I think what you need is to set default value of gender field before you pass the form object to template. Try below.
#app.route('/edit_student')
def edit_student():
student = Student.query.filter_by(id=student_id).first()
student_form = EditStudentForm()
# set default
student_form.gender.default = student.gender
# process it to propagate the change.
student_form.process()
# ... validate on submit
# ....
# ....
return render_template(student_form=student_form)
Related
I am creating a view function to edit the database using a wtform, I want to populate the form with information held on the database supplied by a differente form, My problem is the query that provides the details
I have read the manual https://wtforms.readthedocs.io/en/stable/crash_course.html
and the following question Python Flask-WTF - use same form template for add and edit operations
but my query does not seem to supply the correct format of data
datatbase model:
class Sensors(db.Model):
id = db.Column(db.Integer, primary_key=True)
sensorID = db.Column(db.String, unique=True)
name = db.Column(db.String(30), unique=True)
form model:
class AddSensorForm(FlaskForm):
sensorID = StringField('sensorID', validators=[DataRequired()])
sensorName = StringField('sensorName', validators=[DataRequired()])
submit = SubmitField('Register')
view function:
#bp.route('/sensors/editsensor/<int:id>', methods=('GET', 'POST'))
#login_required
def editsensor(id):
edit = [(s.sensorID, s.sensorName) for s in db.session.\
query(Sensors).filter_by(id=id).all()]
form = AddSensorForm(obj=edit)
form.populate_obj(edit)
if form.validate_on_submit():
sensors = Sensors(sensorID=form.sensorID.data, sensorName=form.sensorNa$
db.session.add(sensors)
db.session.commit()
shell code for query:
from homeHeating import db
from homeHeating import create_app
app = create_app()
app.app_context().push()
def editsensor(id):
edit = [(s.sensorID, s.sensorName) for s in db.session.query(Sensors).filter_by(id=id).all()]
print(edit)
editsensor(1)
[('28-0000045680fde', 'Boiler input')]
I expect that the two form fields will be populated with the in formation concerning the sensor called by its 'id'
but I get this error
File "/home/pi/heating/homeHeating/sensors/sensors.py", line 60, in
editsensor
form.populate_obj(edit)
File "/home/pi/heating/venv/lib/python3.7/site-
packages/wtforms/form.py", line 96, in populate_obj
Open an interactive python shell in this
framefield.populate_obj(obj, name)
File "/home/pi/heating/venv/lib/python3.7/site-
packages/wtforms/fields/core.py", line 330, in populate_obj
setattr(obj, name, self.data)
AttributeError: 'list' object has no attribute 'sensorID'
The error indicates that it wants 2 parts for each field "framefield.populate_obj(obj, name) mine provides only one the column data but not the column name, "sensorID"
If i hash # out the line "edit = ..." then there are no error messages and the form is returned but the fields are empty. So I want the form to be returned with the information in the database, filled in so that i can modify the name or the sensorID and then update the database.
I hope that this is clear
Warm regards
paul.
ps I have followed the instruction so the ERROR statement is only the part after "field.populate_by".
You are trying to pass a 1-item list to your form.
Typically, when you are selecting a single record based on the primary key of your model, use Query.get() instead of Query.filter(...).all()[0].
Furthermore, you need to pass the request data to your form to validate it on submit, and also to pre-fill the fields when the form reports errors.
Form.validate_on_submit will be return True only if your request method is POST and your form passes validation; it is the step where your form tells you "the user provided syntactically correct information, now you may do more checks and I may populate an existing object with the data provided to me".
You also need to handle cases where the form is being displayed to the user for the first time.
#bp.route('/sensors/editsensor/<int:id>', methods=('GET', 'POST'))
#login_required
def editsensor(id):
obj = Sensors.query.get(id) or Sensors()
form = AddSensorForm(request.form, obj=obj)
if form.validate_on_submit():
form.populate_obj(obj)
db.session.add(obj)
db.session.commit()
# return response or redirect here
return redirect(...)
else:
# either the form has errors, or the user is displaying it for
# the first time (GET)
return render_template('sensors.html', form=form, obj=obj)
I just want to know how can I set initial values to empty_form.
I do create the Inlines with initial values for extra forms without problem, but, when user clicks to Add button, the fields I expect it have the initial values show up empty, and I hope it have the same initial values than extra forms.
How could I make the empty_form to be filled with initial data?
Thanks in advance.
Django doesn't really provide a way to set initial values for empty forms. I've found a couple ways to work around this:
Set the field values dynamically in javascript.
Overwrite the empty_form property for your formset.
example:
formset = formset_factory(MyClass, **kwargs)
empty = formset.empty_form
# empty is a form instance, so you can do whatever you want to it
my_empty_form_init(empty_form)
formset.empty_form = empty_form
I had a similar problem and what finally worked for me was using Django Dynamic Formset. What DDF does is instead of using the empty form to create the new formset, it uses one of the extra_forms as a template. The default behavior is to clear all field values from the extra_form before inserting the HTML to the DOM, but you can use the keepFieldValues setting to specify the ones you want to keep.
In my case I wanted to keep all hidden field values:
$(function() {
$('#myForm_table tbody tr').formset({
keepFieldValues: 'input:hidden',
}
});
});
Of course you can bypass Django Dynamic Formsets and implement your own add/delete code with Javascript if you prefer.
Accepted answer didn't work for me, hopefully this will help someone in the future, this is my solution:
Create a new class based on BaseInlineFormSet
Override empty_form
Create a FormSet with inlineformset_factory(formset=YourBaseInlineFormSet)
Create a formset instance and pass parameters to initial on the formset instance
Add the field on the HTML as usual
I used BaseInlineFormSet, but probably will work with other types of FormSet
verification is the name of the field for my example.
forms.py
class YourBaseInlineFormSet(forms.BaseInlineFormSet):
#property
def empty_form(self): # This is almost the same as Django 3.1 code
form = self.form(
auto_id=self.auto_id,
prefix=self.add_prefix("__prefix__"),
empty_permitted=True,
use_required_attribute=False,
initial={"verification": self.initial_extra[0]["verification"]}, # This is the extra parameter
**self.get_form_kwargs(None),
)
self.add_fields(form, None)
return form
YourFormSet = forms.inlineformset_factory(
SomeObject,
SomeRelatedObject,
fields="__all__",
widgets={"verification": forms.HiddenInput},
formset=YourBaseInlineFormSet,
)
views.py
from .forms import YourFormSet
def your_view(request):
formset = YourFormSet(
data=request.POST or None,
instance=object,
queryset=object.related_objects.all()
initial=[{"verification": verification} for a in range(FormSet().total_form_count())],
)
return render(request, template, context={'formset': formset})
template.html
<div id="empty_form" style="display:none">
{{ formset.empty_form }}
</div>
Working on Django 3.1
There is at least one way to do this: Specify the default value on your model Field.
Of course, this may have side effects, depending on your implementation of the model.
As #jkk-jonah mentioned, BaseFormSet does not provide a way to set initial values in the empty_form. However, a small change can provide a simple solution.
The following provides a way to supply the FormSet instance with empty initial values without disrupting its base behavior.
from django.forms.formsets import BaseFormSet
class FormSetWithDefaultEmptyFormInitials(BaseFormSet):
"""This formset enables you to set the initial values in ``empty_form``.
Usage: ``formset_factory(..., formset=FormSetWithDefaultEmptyFormInitials)``
"""
def __init__(self, *args, **kwargs):
if 'empty_initial' in kwargs:
self._empty_initial = kwargs.pop('empty_initial')
super().__init__(*args, **kwargs)
def get_form_kwargs(self, index):
"""Augmented to return the empty initial data
when the index is ``None``,
which is the case when creating ``empty_form``.
"""
if index is None:
kwargs = self.form_kwargs.copy()
if self._empty_initial:
# Assign the initial value passed to the Form class.
kwargs['initial'] = self._empty_initial
else:
kwargs = super().get_form_kwargs(index)
return kwargs
Then to use this you'd do something like:
NonEmptyFormSet = formset_factory(
BringYourOwnForm,
min_num=1,
extra=1,
formset=FormSetWithDefaultEmptyFormInitials,
)
# Let's say your form has name and address fields...
empty_form_initial_values = {'name': 'default name', 'address': 'default address'}
formset = NonEmptyFormSet(empty_initial=empty_form_initial_values)
asset formset.empty_form.initial == empty_form_initial_values
In my implementation empty_form is used to provide a template for frontend javascript to add additional forms to the formset. Thus, this allows me to set the initial values for that all of the forms in that formset.
Note, this does not take the place of initial values to the minimum number of forms within the formset (e.g. formset_factory(min_num=2, ...)). Therefore, it is necessary to assign those through the standard initial keyword argument.
Tested with Django 3.2.
See also the standard implementation of get_form_kwargs.
This partially extends the answer given by #RobertPro. Or at least, I used their answer as the stepping stone to my own solution.
I have a huge django form and I need to create dict where keys are field id in template and values are initial values?
Something like this:
{'field1_id_in_template': value1, ...}
Does somebody know how do that?
I can add prefix 'id_' for each field name in form.fields dictionary but I can have a problem if somebody change id for widget.attrs
This is method of CBV:
def post_ajax(self, request, *args, **kwargs):
form = ChooseForm(request.POST, log=log)
if form.is_valid():
instance = form.save()
inst_form = InstanceForm(instance=instance, account=request.user)
fields = {}
for name in inst_form.fields:
if name in inst_form.initial:
fields[inst_form.auto_id % name] = inst_form.initial[name]
return HttpResponse(
json.dumps({'status': 'OK','fields':fields},
mimetype='appplication/json'
)
assert False
And this a reason why I do that:
With this response I can write something like this on client. Now I don't need to manualy initialize all fields on the page
function mergeFields(data) {
for(var id in data) {
$("#"+id).val(data[id]).change();
}
}
Originally added to the question body itself reference.
If you have the auto_id set to True then you can get the id with form_object_instance.field_name.auto_id. With that in mind you can create your dict by iterating over the form object.
I am just wondering why you would need to do such a processing as the form object is usually used to encapsulate such behaviors...
you can try getattr.
For example, you have a known key list as
['field1_id_in_template', 'field2_id_in_template', ...]
Then:
my_values = dict()
for key in key_list:
value = getattr(your_form, key)
# now do something with it
my_values[key] = deal_with(value)
I have a form that asks the user to enter in their zip code. Once they do it sends them to another form where there is a field called 'pickup_date'. This gets the value of the zip from the previous field and gets all of the available pickup_dates that match that zip code into a ChoiceField. I set all of this within the init of the model form.
def __init__(self,*args,**kwargs):
super(ExternalDonateForm,self).__init__(*args,**kwargs)
if kwargs:
zip = kwargs['initial']['zip']
self.fields['pickup_date'] = forms.ChoiceField(choices = self.get_dates(zip))
elif self.errors:
zip = self.data['zip']
self.fields['pickup_date'] = forms.ChoiceField(choices = self.get_dates(zip))
The problem I have is when there are other errors on the form. I use the elif self.errors to regenerate the possible choices but it doesn't default to the original selected option. It goes back and defaults to the first choice. How can I make it so it's default option on form errors is what was originally posted?
Change self.fields['pickup_date'] to self.fields['pickup_date'].initial and see if that helps.
I got it to work after playing around for a while. Above, I was setting all the dynamic choices with a get_dates() function that returned a tuple. Instead of doing that I returned a field object like this using a customized ModelChoiceField instead of a regular ChoiceField....
class MyModelChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return obj.date.strftime('%a %b %d, %Y')
Dates function
def get_dates(self,zip):
routes = Route.objects.filter(zip=zip).values_list('route',flat=True)
pickups = self.MyModelChoiceField(queryset = PickupSchedule.objects.filter(
current_count__lt=F('specials'),
route__in=routes,
).order_by('date')
)
if not pickups:
pickups = (('----','No Pickups Available At This Time'),)
return pickups
in the init i set the value for self.fields['pickup_date'] like so..
self.fields['pickup_date'] = self.get_dates(zip)
I have a form 'in the wild' that takes many different variables - which may or may not be populated.
try:
app_version = request.REQUEST["appVersion"]
except:
app_version = ''
try:
app_name = request.REQUEST["appName"]
except:
app_name = ''
try:
app_code_name = request.REQUEST["appCodeName"]
except:
app_code_name = ''
Is there a tighter way to accomplish this?
app_version = request.REQUEST.get("appVersion", "")
get(key, default) is a method implemented on Python dicts. If the key exists in the dictionary, its value is returned; if the key does not exist, the specified default value is returned. In Django, request objects are dictionary-like objects, so get is also defined for them in the same manner.
If these variables are intended to populate a form, then you can safely pass the request.POST object directly into the form constructor.
if request.method == 'POST':
form = MyForm(request.POST)
The form will automatically pass the correct values to the correct form fields and use defaults for keys that don't exist and will still create blank fields for missing keys (see addendum).
If you are trying to process a form, it is still better to create a form object as above, and read out the values from that object.
if request.method == 'POST':
form = MyForm(request.POST)
if form.is_valid():
# You may process these variables here
print form.appVersion
print form.appName
print form.appCodeName
Remember, validation code is best placed in the form class as well. That way, if form.is_valid() returns True, then you know you have a clean dataset to work with.
Note: Django docs recommend using request.POST or request.GET directly rather than the amalgamated variable request.REQUEST, as it is more explicit.
Addendum:
It is important to understand the difference between bound and unbound forms in this case. If you create an unbound form with form = MyForm(), then when the form is instantiated, it will fill in all fields with the initial property of each field (if it exists). For example, with this code:
from django import forms
class MyForm(forms.Form):
appVersion = forms.CharField(initial='1.0')
appName = forms.CharField()
appCodeName = forms.CharField()
the form will be initialized with appVersion having a value of '1.0'. However, if you bind a POST request to a form like this: form = MyForm(request.POST), then the initial properties are ignored. That means if the POST dict does not include an appVersion key, then that field will be left blank. As long as the field is not required, your form will still validate, and you can modify form.appVersion in the view after validation.
If you have many fields, a more compact version might be:
defaults = { 'field1' : 'val1', 'field2' : 'val2', ...}
defaults.update(request.POST)