Django Admin: Need to conditionally display fields - django

What is the best way to conditionally display a field in the admin depending upon the values of other fields?
In particular I'm thinking about the add_form and change_form. Whenever a certain choice is selected I'd like to hide or disable some fields.
I'm thinking that this might require a javascript solution, but am wondering if there is a better (i.e. builtin) way to do this.

Bernhard is right. You might be able to hack the admin view and template to conditionally show/not show widgets for a field, but if you want to do it dynamically based on user behaviors in the admin, you'll be using javascript.
It's not so terrible, though. At least the Django admin templates have model- and instance-specific ids to give you granular control over your show/hide behavior.

My answer may sound esoteric - but I suspect the design direction you may be taking could benefit from some reconsideration. When an interface requires that much TLC to resort to AJAX to make for a superior UX I am inclined to not use Admin interface for that.
My personal view of the Admin interface of Django is that it is a great freebie that gives me an instant CRUD view at a basic level. I would refrain from piggy backing on it for those who need a more user friendly interface (even if some of these users are handling admin functions). You will acquire technical debt in trying to do these type of Ajax UI/UX and complex form validations using the Admin interface.

I think you should be able to create your own ModelForm and specify that the admin uses that (https://docs.djangoproject.com/en/1.7/ref/contrib/admin/#django.contrib.admin.ModelAdmin.form).
Use the _init__() method of the form to selectively display the fields.
I will give it a try and update this answer if it works.
(Actually re-reading the question, it depends. If "values of other fields" is set before the page is loaded, this idea should work. If you want an instant response - click one field and another appears/disappears, yes you will need JavaScript).

Related

django - Add another model without Popup

Is there any magic why to do this in admin panel of django?
Let me know
Off the top of my head, you could use JS to grab the popup link and load the HTML in a div on the page. But that means you need to override the admin template. This QA should be helpful.
It also means you need to capture the saving of the new house. So, when someone presses save, depending on the response, the div either closes or shows the errors WITHOUT refreshing th page. I'm not sure but I think you'll also need to override the admin view that does this to send back json responses.
OR
You could use JS to mute that link and call up your own url, which would allow you to create your own view with your own custom form that does this. This would give you a bit more control without having to hack away at the Admin functionality.
e.g /house/ajax_add
You'll need to refresh the options in the House dropdown though. So I don't think you can avoid extending the template, now that I think about it.
It seems like a lot of trouble, really. No magic way that I know of, but it's possible.
To avoid popups, you might want to look at https://github.com/FZambia/django-fm:
Django-fm allows to create AJAX forms for creating, editing, deleting
objects in Django. This is a very personalized approach to quickly
build admin-like interfaces.
A live example can be found on http://djangofm.herokuapp.com/.
I'm not sure how this integrates with the current admin site, but with some changes it should not be hard.

django: routing users through a complex app with class-based views

I'm an advanced beginner at django and python. I'm writing an app to handle registration and abstract submission for a conference, and I'm trying to use class-based views. Users get an emailed link that includes their registration code in the url. Starting at this url, users move through a series of views that collect all the necessary info.
The complication comes from the fact that users often stop half way through, and then want to complete the process several days or weeks later. This means that they might continue from the current page, or they might just click that original link. In addition, after several weeks they might have missed certain deadlines, so, e.g., they can no longer submit an abstract (but they can still register). Along the way, they have checked or unchecked various options that also influence the path they should take through the app.
My question is: where is the best place to put the logic that determines if the user is currently allowed to view that page, and if not, the best url to redirect them too? I thought I would create a custom view class that, e.g., overrides the dispatch method to include global checks (e.g., is conference registration open?), and then subclasses could add additional checks (e.g., has the user entered all the necessary info for her abstract?). The problem I ran into was that the checks were run in the wrong order (I want base class checks run first). I then started investigating custom view decorators or custom middleware. At this point I realized I could use some expert advice about which approach to take. (If it matters, I am not using the django authentication system.) Thanks in advance.
Maybe the form wizard could help you managing the viewing sequence.
In general django greybeards advocate keeping row-wise logic in Models, and table-wise logic in Managers, so it seems appropriate to keep complex view logic in a master view class.
The wizard class can help maintain the order of the views, but to resume an out-dated session you may need to do some model saves (which could get too complex very quickly) or some cookie handling.
In the past, when presented with a similar situation, I took the simplest route and separated user registration and the task that the user wants to perform (event registration). The user registers once but if they fluff up the event registration, they just have to log back in at a later date and do it again (their hassle - not yours!).

How to add report section to the Django admin?

I want to implement a report section in Django admin. This would mean adding a custom section in the admin homepage where instead of a list of models I would see a list of reports. I want to use Django's admin tables with filters, sorting, everything if possible.
What would be the "best" way of achieving this? I realize this is a "big" question so I'm not asking for code snippets necessarily, a summary of needed actions would be just fine :)
P.S. Be report I mean a "made up" model by custom queries (queryset or how it's called).
P.S.2 Maybe this question should be something like: How to use Django admin tables functionality in own admin view?
P.S.3 Or maybe there is a way of providing to the existing admin interface my own data. This way I don't have to do anything else. I just want to say instead of a model take this data and display it in a nice table which I can sort, filter etc etc.
So you are attempting to add in new pages into the django admin.
This section explains to you exactly how you can do so - https://docs.djangoproject.com/en/dev/ref/contrib/admin/#adding-views-to-admin-sites
The basic idea is to add in new urls that you want in your urls.py as if you are adding urls for your "front end" pages. The key difference is that these new urls you are adding should start with ^admin/ and would look something like ^admin/my_special_link_in_admin and this url will point to your own custom view function at a location you so prefer.
E.g.
(r'^admin/my_special_link_in_admin/$', 'my_custom_admin_app.views.special_admin_page'),
So this is the way for complete customization. There's a very good tutorial which I refer to here - http://brandonkonkle.com/blog/2010/oct/4/django-admin-customization-examples/
In addition, if you don't want to do too much work, consider using Django Admin Plus - https://github.com/jsocol/django-adminplus
Or a django-admin-views - https://github.com/frankwiles/django-admin-views

Should I modify/extend the admin interface, or write my own CRUD views/templates?

I'm trying to write a simple CRM app in Django; partly as a learning exercise and partly for in-house use.
My schema is slightly complex, as rather that have a single Contact model (with a home phone, work phone, home email, etc.), I have stripped down Cntact model plus a Phone model, an Email model, etc., with a ForeignKey pointing back to a Contact. The point is to let Contacts have an arbitrary number of phone numbers, email addresses, etc. Simple, right?
I have some working views and templates for displaying the data - no issues there. And with only a very small amount of poking at admin.py I have a um...eight different TabularInlines set up, and the admin interface works to create and edit the data...but it's ugly and clunky to the point of unusability, and of course there's no conception of permissions or anything. I'm also not really a fan of having a completely different interface for displaying and searching through the data than for editing and adding contacts...I'd like as much as possible to be done inline, so that I can search for a name, look at the record, click "add note", have it popup a form, fill in the details, click submit, and be done, all with AJAXy goodness so there's no page reloads.
Question: Should I plug away at modifying the admin interface to try and make it usable for a user-facing app? And if so, can anyone point me to a good guide or example where someone has really changed the admin interface to make it work for user-facing CRUD operations?
Or should I just go ahead and write my own CRUD views? And if so, can anyone point me to a good guide or example where someone has written custom CRUD views that work with lots of ForeignKeys and inlines? Ideally I want a form that displays a single Contact, all his Email records, plus a blank form to add a new Email record, plus a button to add more blank forms, plus his Phone records, plus a blank form, and so on for all 8 of my associated models.
(Or am I thinking about this all wrong? Any advice appreciated.)
For our intranet, we use ModelAdmin subclasses (not mounted on the admin site via admin.site.register) for most of our C(R)UD views. By using custom templates for the views, it doesn't look like Django admin at all. What is very convenient though, is that it already handles all the validation/saving for us.
In general, I found admin-"hacking" quite useful to quickly write up C(R)UD views and usually with relatively small changes to your ModelAdmin subclass, you can make it work for your use case.
So I'd vote for use ModelAdmin, but not the one you use in admin, hook a different template and come up with some fancy CSS.
I successfully created a software on top of admin.
The admin hooks (these days) allow very fine-grained customizations, i.e. in general you only need to touch what you want to change.
The changes can go from a trivial cosmetic adjustment to a complete swap-out:
If you provide templates/admin/base.html your admin site can look any way you like. And of course, a navigation bar at the top could include links to some of your own views. Watch out not to hardcode URLs in your links, always reverse.
You can overload ModelAdmin's "change_view", "changelist_view" etc. and swap them for your own views. For example I replaced a default changelist and its simple filtering with a search interface that allows dynamic queries to be built, result columns to be customized by the user, and loading/saving of these searches. That didn't affect any of the other views of that ModelAdmin.
Overloading a ModelAdmin's "get_urls()" let's you rewrap existing admin urls to go to your own views. I did the latter for one model where I wanted the simple Add screen to be replaced by a totally customized Wizard (only leaning on ModelForm).
Don't forget the simplest approach, esp. regarding your "AJAXy goodness": Just define "css" and "js" in your ModelAdmin's Meta. Want to move an inline from the bottom to sit between third and fourth field, and that's not possible via parameters? A one-liner in jquery.
Check out "django-grappelli" for an example of how to improve admin look and feel.
What did you mean by "and of course there's no conception of permissions or anything"?

Is there an easy way to provide a custom django admin action without allowing changes to models?

I have a custom action on a model Foo all set up and ready to go, complete with a new permission I've made.
Problem is, my administrators need the can_change_foo permission to view a change list and perform that custom action (which I don't want to award).
Is there an easier way to set this up without rewriting the model list admin view?
There is a horrid hack I can think of... Completely untested, obviously...
You could disable all other actions by overriding get_actions() and only allow for your custom action. Then you could follow T.Stone's suggestion here and completely disable links to edit individual instances of the model. What that would allow you to do is give your users the can_change_foo permission knowing that the only action they would be able to perform was yours.
Not pretty... Especially the part about not linking to the edit page...
Is re-writing the list admin view that bad? :-)
I ended up overriding the changelist_view() method on my ModelAdmin class, copying the defaults from django and just commenting out the permissions check. The list (at least the way I have it configured) doesn't have links to edit the individual objects, and even if it did, django raises a PermissionDenied if you try and edit an individual object. (since I never awarded the can_change permission).
It's a hack, and some monkeypatching, but until there's a separate permission for viewing a changelist, it works pretty well.