Global Variables in Django Admin Site

Question

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.

Answer 1

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.