I want to create a dynamic admin site, that based on if the field is blank or not will show that field. So I have a model that has a set number of fields, but for each individual entry will not contain all of the fields in my model and I want to exclude based on if that field is blank.
I have a unique bridge identifier, that correlates to each bridge, and then all of the various different variables that describe the bridge.
I have it set up now that the user will go to a url with the unique bridgekey and then this will create an entry of that bridge. So (as i am testing on my local machine) it would be like localhost/home/brkey and that code in my views.py that corresponds to that url is
However, not every bridge is the same and I have a lot more variables that I would like to include in my model but for now I am just testing on two : prestressed_concrete_deck and reinforced_concrete_coated_bars. What I want is to dynamically create the admin site to not display the prestressed_concrete_deck variable if that field is blank. So instead of displaying all of the variables on the admin site, I want to only display those variables if that bridge has that part, and to not display anything if the field is blank.
Another possible solution to the problem would be to get that unique identifier over to my admins.py. I cant figure out either how to get that individual key over as then I could query in the admins.py. If i knew how to access the bridgekey, I could just query in my admins.py dynamically. So how would I access the brkey for that entry in my admins.py (Something like BridgeModel.brkey ?)
I have tried several different things in my admin.py and have tried the comments suggestion of overwriting the get_fields() method in my admin class, but I am probably syntactically wrong and I am kind of confused what the object it takes exactly is. Is that the actual entry? Or is that the individual field?
Just override the get_fields method in your ModelAdmin class.
You can check the obj is passed as function argument so you can check which fields are empty. The function needs to return a tuple so, you would check if field1 is None and then return (field1, field2, field3) or (field2, field3) depending on the value of field1.
I was using Django 1.6 which did not support overriding the get_fields method. Updated to 1.7 and this method worked perfectly.
Related
I am creating a web-app w/ Flask + Flask-WTF that has CRM-like features as a project. My current database (MongoDB) structure is I have:
Users who can login,
People who are assigned to users, and
Records who are assigned to people.
People have various fields to be filled out (Name, Phone Number, Email, etc).
I want Users to be able to create custom fields for people. I am trying to plan out how to implement this from a database design perspective. My initial thoughts are to:
For each field created, add a new field without a value for each People assigned to the user.
Use a for-loop to dynamically create the form class by looping through each field-value in my database and excluding non-required ones.
Use a for-loop to dynamically output the web form by looping through each field-value in my database and excluding non-required ones.
Another idea I have is:
For each field created, add the custom field, with a parentRecord equal to the User ID to a new MongoDB collection.
Use a for-loop to create the form class & web form dynamically, but I wouldn't need to exclude non-required ones as the only fields in the collection would be the custom ones, and wouldn't include any special data points that don't get displayed.
So my questions are:
Will my ideas above work?
Which one is better?
Is there a better way?
I decided to create a customfields MongoDB collection that has a parentRecord as the User.
I faced a few challenges:
I had to dynamically create a form via flask WTF. I ended up using wtforms_dynamic_fields to accomplish this. I then used a for-loop to dynamically generate each form in Jinja. I simply queried the customfields DB where the parentRecord matched the logged in User, and then created custom fields based upon the values saved in customfields.
The second issue I faced was getting the data from the submitted form and then building a MongoDB-friendly list to insert a new record with when creating new record. This was accomplished by using request.form.items() and iterating through them and using list.update() to add all of my required fields to a list.
In my Django models, I have two models : one called Site and the other SiteFeature.
Object-wise, it is very clear how this should work : every instance of the Site class should have as property a list containing instances of the SiteFeature class, simply because the SiteFeature objects should only exist in relation to a Site object.
Database-wise, it is also very clear how it should work : the SiteFeature table should contain a not-nullable column referencing the primary key id column of the Site table, with a foreign key.
But in terms of Django ORM, I don't know how to code this.
Based on this question, and this other example, it seems the classical way to proceed works the other way round :
The Site model class contains no ORM model field referencing the SiteFeature list.
Instead, the SiteFeature ORM model class has a ForeignKey field referencing the Site class.
I see there is a way to code this out : by adding a function to the Site model class that searches all the related SiteFeature, and make this function a property (decorator #property):
#property
def site_features(self):
return SiteFeature.objects.filter(site_id=site_id)
But that leaves me doubts :
The proper logic for me would also be that when I save, update or create an instance of the Site class, it would also automatically save / update / create the instances of SiteFeature that are related to it. (same thing for deleting the object, but that can be covered by the on_delete=models.CASCADE parameter of the ForeignKey field).
I could add my own save_with_features / update_with_features / create_with_features methods that cascade all but I am not sure what would happen in case of calls made automatically by Django to the standard save / update / create such as in bulk operations.
This problem seems to basic that I suppose there is already a proper way to do it. How would that be ?
Eventually, I solved the problem with the sitefeature_set Manager.
Reference: https://docs.djangoproject.com/en/3.0/topics/db/queries/#following-relationships-backward
This was my original question, but it was not answered and so I thought Id post again with some of the strategies that I have tried, and be a little more specific.
I want to create a dynamic admin site, that based on if the field is blank or not will show that field. So I have a model that has a set number of fields, but for each individual entry will not contain all of the fields in my model and I want to exclude based on if that field is blank. My project is about bridges, and so to put it in practical terms I have a model that has every bridge part in it (this roughly is equivalent to 100), but each individual bridge (mapped to each unique brkey) will not have all 100 bridge parts. And so, I can prepopulate all of the fields it does have, but then the admin site has 100 other fields, and I would like to not display those fields that were not used on my admin site for that specific bridge, but those fields will differ with pretty much every bridge.
Like I said before, I have a unique bridge identifier(a unique 15 digit string), that correlates to each bridge, and then all of the various different variables that describe the bridge.
I have it set up now that the user will go to a url with the unique bridgekey and then this will create an entry of that bridge. So (as i am testing on my local machine) it would be like localhost/home/brkey and that code in my views.py that corresponds to that url is
Is this a final route that I have to take? I am very new to JavaScript and so I do not want to take this route but I will if I have to. Also does Django use Javascript in anyway that is syntactically different? If so I cannot find any Django documentation on incorporating Javascript into my admin site.
A final option that I have exhausted is to use global variables. Instead of having the url that creates the entry in my Views.py, I placed it in my admins.py, and had my modelAdmin class in there as well, so like this.
admins.py
-set up global variable
bridgekey_unique = " "
If I can find a way to either pass that unique bridge key to my modelAdmin class, or figure out if that said field is blank because the bridge doesnt have that part, I will be able to achieve what I want without using Javascript. I have tried a lot of variations of all two of theses strategies to no avail, but have not tried the JavaScript idea as I dont really know any javascript at all.
Sorry for the lengthy post, but people said I wasnt specific enough. Any help would be greatly appreciated.
I didn't read all of that - sorry, there's too much. But I did notice your comment that you expect to access in your modeladmin definition a variable that you set in your view. That can't possibly work.
Anything at class level is always executed when the module containing the class is first imported. That is when the server process starts up, so there is no possible way anything done in the view can have happened yet.
You almost never want to have any logic at class level. You need to put it in methods, which are called at the relevant time. In this case, you probably need to use the get_fields method.
Edit
Looking further up at your attempt at a get_fields method, I can't see at all what you are trying to do here. 'prestressed_concrete_deck' is a literal string, and could never be None, so neither of your conditions can ever be true. And as to your question about what the parameters are, the documentation for that method explains clearly that obj is the object being edited.
I'm a newbie and right now I'm using Django forms to show some fields. One of these fields is a ModelChoiceField this show correctly model data, but I don´t know how I can fill a CharField later of select a option in the ModelChoiceField.
How I can make send the value of option selected for obtain the data that i need for later show this in a CharField, this is possible make directly from a djangoForm or do I need a new view to return the value?
There are two ways to achieve what you want I think:
Provide an initial value for your form value.
Bind your form to some data.
See this related stack overflow to provide initial values.
See Django's documentation on forms for binding data. There are two kinds of form states: bound and unbound. To create a bound form, you just need to create an instance of your form with some data: MyForm({'data-key1': 'data-value1', ...}).
I'm new to Django, and I haven't found the answer yet in the extensive documentation. I'm asking for pointers to research, not for working code. That being said, here's my problem:
In one of my models theres a BooleanField (it gets rendered in the admin form as a checkBox). Let's call it 'A'. It only makes sense to edit other field (say, CharField 'B') if A is checked.
So, is there a way to make B read only, or even changing its content to an empty string, dinamically, if A is checked? Thank you.
(Django 1.5.2, Python 2.7.5)
You're going to need several things to make this work. You may be able to skip some of them depending if you mainly care abut the UI, or the data integrity in the db.
Since the user can (presumably) check/uncheck Field A on the client-side you need some Javascript to enable/disable the appearance of Field B. These docs show how to load custom JS in your ModelAdmin class:
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#modeladmin-asset-definitions
In your ModelForm you may want to do some check in the __init__ method against the value of self.instance.field_a and substitute some kind of ReadOnlyWidget for Field B for the initial display of the form. These docs show how to give your ModelAdmin a custom form class:
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.form
If you are writing some Javascript to do that dynamically it make be easier to skip this step and just do it client-side.
Finally you can use Django model validation to ensure that Field B is saved with a null value if Field A is checked:
https://docs.djangoproject.com/en/dev/ref/models/instances/#validating-objects