How can I save and retrieve a django form state to database?
Users are filling in a lengthy survey and want to save the survey state in between.
My ideas were:
Option 1. Saving request.POST to database (doesn't work), and then:
SurveyForm(my_saved_form_state or request.POST)
Option 2. Saving cleaned_data to database (does work) and then:
SurveyForm(my_saved_form_state or request.POST or None)
but the cleaned_data doesn't instantiate the form! Only the full request.POST (a QueryDict) seems to do that. How to proceed?
So I solved it, finally.
Saving the POST data to database:
postdata = {}
for key in request.POST.iterkeys():
if len(request.POST.getlist(key)) > 1:
postdata[key] = request.POST.getlist(key) # for checkboxes
else:
postdata[key] = request.POST.get(key, u'') # for all others
person.saved_answers = postdata
person.save()
Loading it from database:
saved_answers = ast.literal_eval(person.saved_answers) # convert unicode string into python object
SurveyForm(saved_answers)
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 am getting date/time info from ajax to Django. I am using 2 different views. event_edit is working fine, but event_edit_new does not work. It return an error Enter a valid date/time.
My question is what is making difference. They are getting exactly same information but one is ok while other one is not.
Javascript code making ajax request:
var ajax_test = function(event){
$.ajax({
url: '/scheduler/event/' + event.eventId + '/edit2/',
method: 'POST', // 'POST' or 'PUT'
data: {
'Note': event.title,
'OpNum': event.resourceId,
'StartTime' : event.start.format(),
'StopTime' : event.end.format(),
'ScheduleNum': event.eventId,
}
}).done(function(res) {
console.log("done", res)
}).fail(function(error) {
console.error("error", error)
console.log(event.start.format());
});
}
2 views
def event_edit(request, pk):
schedule = get_object_or_404(Schedule, pk=pk)
schedule.OpNum = request.POST.get('OpNum')
schedule.Note = request.POST.get('Note')
schedule.StartTime = request.POST.get('StartTime')
schedule.StopTime = request.POST.get('StopTime')
schedule.ScheduleNum =request.POST.get('ScheduleNum')
schedule.save()
return HttpResponse('ok')
def event_edit_new(request, pk):
schedule = get_object_or_404(Schedule, pk=pk)
if request.method =='POST':
form = ScheduleForm(request.POST, request.FILES, instance = schedule)
if form.is_valid():
form.save()
return HttpResponse('ok')
else:
return HttpResponse('error')
else:
return HttpResponse('done')
In your first view, there is no validation applied to user data input:
schedule.StartTime = request.POST.get('StartTime')
schedule.StopTime = request.POST.get('StopTime')
request.POST does not validate any data so that will grab user data exactly as submitted and set it on a model. Note that it might work but it is not guaranteed to work if user will ever send datetime format the application does not understand. For example try submitting something like "invalid date" and you should get 500 error.
Your second view on the other hand uses a Django Form to validate user input. By using a form you are validating user input before processing it in any way. You did not paste how your form is structured however if you are getting Enter a valid date/time. this means Django form did not validate one of the datetime fields. There are couple of reasons why that might be:
submitted datetime does is not one of input_formats for a DateTimeField. You can customize the formats with:
class MyForm(forms.Form):
datetime_field = forms.DateTimeField(input_formats=['%Y-%m-%dT%H:%M:%SZ', ...])
submitted datetime is not one of Django's default supported datetime formats.
You can customize them with DATETIME_INPUT_FORMATS setting.
I am trying to get a ID for a related Model. I have tried several things but can not figure it out. below is the code I am using.
def assign_load(request):
form = DispatchForm(request.POST or None)
loads = Load.objects.all().filter(active=True, dispatched=False, picked_up=False, delivered=False,
billed=False, paid=False)
context_dict = {'dispatch' : form, 'load' : loads}
if form.is_valid():
save_it = form.save()
save_it.save()
new_dispatch = Dispatch.objects.all().filter(id=save_it.id)
print(new_dispatch.model.load_number.pk)
return HttpResponseRedirect('/dispatch/dispatch/')
return render(request, 'dispatch/dispatch_form.html', context_dict)
new_dispatch is the newly created record that has a one-to-many releation with a model called Loads. I need to get the load_number PK when I try to print just the new_dispatch.model.load_number I get back the following.
<django.db.models.fields.related_descriptors.ForwardManyToOneDescriptor object at 0x0000029016E34710>
but what I need is the ID for that record so that I can updated some fields.
Thank you very much for your help, I am new to the Django world and trying to figure this stuff out.
Use Dispatch.objects.get(id=save_it.id) instead of Dispatch.objects.all().filter(id=save_it.id)
i created a form to save a post into db for my blog project. I've designed index page. now i am tryin to create a form to create new posts. before that i was using ' manage.py shell'
here is my view :
def addpost(request):
form = addForm()
if request.method=="POST":
titleform = request.POST['title']
bodyform = request.POST['body']
checkform = request.POST['isdraft']
if form.is_valid():
n = Post(title = titleform, body = bodyform, isdraft=checkform)
n.save()
return HttpResponseRedirect('/admin/')
else:
pass
return render(request,'userside/add.html',{'form':form,})
my model.py:
class Post(models.Model):
title = models.CharField(max_length = 100)
body = models.TextField()
slug = AutoSlugField(populate_from='title',unique=True)
posted = models.DateField(auto_now_add=True)
isdraft = models.BooleanField()
def __unicode__(self):
return self.title
#permalink
def get_absolute_url(self):
return ('view_blog_post',None, {'postslug':self.slug})
class addForm(forms.Form):
title = forms.CharField(max_length=100)
body = forms.CharField(widget=forms.Textarea)
isdraft = forms.BooleanField()
if i submit form as 'isdraft' field is False(unchecked) ; it gives error like:
MultiValueDictKeyError at /admin/addpost/
"Key 'isdraft' not found in "
and if i submit the form as 'isdraft' field is True(checked) ; it gives nothing. just refreshing form. no adding data into db.
i am doing sth wrong..
thank you
edit : Dmitry Beransky's answer worked for checkbox error. but it still doesnt add any data into db. just refreshes the form.
The whole point of using a form is that it takes care of validation and cleaning, that is converting values to the proper data types. That's why you should be accessing form.cleaned_data rather than reques.POST, and you should be doing it inside the if form.is_valid() check.
Edit
I've just noticed that you're never passing request.POST to the form. So form.is_valid() will never be true.
Please go back and read the documentation about using a form in a view.
If a checkbox is not checked in your HTML form, it's name/value is not going to be included in the data that the browser sends to your server. Which meanst that the request.POST dictionary is not going to contain an entry for 'isdraft' which in turn will cause a key error when you try to read the isdraft value. A solution is to change the way you read the value from the posted data to:
checkform = request.POST.get('isdraft', False)
rather than throw an error if isdraft isn't found in the dictionary, this will set checkform to False (the default value in case of a missing key)
Maybe your form does not validate at all. Have you checked if your code even reaches those lines after the if form.is_valid() statement ? If they do, what you've done there is right and should create the db row for your new entry, though you could have used
Post.objects.create(....) , and that would have taken away the need for calling the method save().
Some points though:
instead of checking for request.POST , check for request.method == 'POST' , cause there might be a post which has an empty POST dict ( in case no arguments have been submitted ), in that case request.POST fails to provide the right check .
see the docs for more info : request.POST
instead of using request.POST['var_name'] , use request.POST.get('var_name', 'default_value') , cause doing this like request.POST['var_name'] might result in some exceptions ( in case for example the argument is not provided , like what happened for your checkform variable )
Try accessing those variables through form.cleaned_data
and finally , you don't need the else statement in the end , just use the indentation :)
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)