Franken-Views

Sometimes overwriting methods just isn't enough. 0:00 You need to show a model detail and a form for editing that model in the same page 0:02 and you don't want people to just read the data in the form. 0:06 So what do you do? 0:09 Well, the first solution most people try is just throwing a form into the context. 0:12 That works but then you have to reimplement a lot of form view or 0:15 it's children in the detailView and yeah, 0:18 frameworks shouldn't make you do more work but Python classes are pretty malleable. 0:21 Maybe you could just combine the two classes together to make a new 0:25 Franken class. 0:28 This can actually work better than my introduction might have 0:31 led you to believe. 0:33 At least, that is if you combine just the right view classes in 0:35 just the right order. 0:38 More often than not though, 0:40 you're going to want some combination that's, you know, full of headaches. 0:41 So, to start off, let me show you one that's not terrible. 0:45 So, I'm going to come up here to the detail view, and 0:48 I want the detail view to be able to like update a record. 0:54 So, detail view, update view. 0:58 I have to set my fields, so fields is equal 1:02 to name practice location and coach. 1:08 The models are gonna be models.team and 1:13 the template name is going to be teams/team_detail.html. 1:17 Cuz that's the template I already had set up, that's the template I want to use. 1:23 Okay, and I wanna make sure that it's using it. 1:27 So now I'm gonna come over here to team_form and 1:29 I'm gonna copy the form here because I don't wanna have to type it again, right? 1:32 All right. 1:38 And then in team detail, before this update <hr> I wanna put in a new <hr>. 1:39 Actually, I'm gonna put a if user is equal to team.coach, 1:45 cuz user is the user who's currently requesting the page. 1:52 So if that's the case then I'll put in my form and we should be good to go. 1:59 So if I come back over here and I select the Tigers and so 2:06 now we can see, here's the form and I can update this. 2:11 So I could be like Tiger Tamers because they changed their name. 2:14 Save. There you go and 2:21 now they're called the Tiger Tamers. 2:23 So, awesome. 2:26 So it worked. 2:27 It did exactly what we wanted, but when I asked you to first join me in work spaces, 2:28 I said it doesn't always go super smoothly. 2:33 So, I think it's a great idea to be on this page and be able to 2:36 create a new team straight from this page, right, at least, for authenticated users. 2:44 I probably don't want just any random person doing this and 2:48 I would probably actually move this into a modal or something like that, but for 2:52 now I'm just going to get it on the page and my UIUX designer 2:56 teammate can figure out the best interface for it later. 3:01 Okay, so back over here in views.py and and here on this list view, 3:05 I'm going to add in the create view and I mean, this worked before. 3:13 So give it a try. 3:19 So context object I don't want to change. 3:21 Fields, I think I've typed that like four times now so I'm going to copy and paste. 3:23 And template name is going to be team'steamlist.html. 3:29 There I go, okay. 3:34 And then of course I need to add the form into the template. 3:37 So here we go. 3:43 We've got our teams there. 3:44 Let's add a new thing here and 3:47 I'll say if user.is_authenticated, 3:50 then I'll toss in an HR, toss in the form and okay. 3:56 Nothing special there, all right, so, should be ready to go, 4:04 should be able to just refresh this page and get what I want. 4:08 And I have an AttributeError. 4:11 TeamListView object has no attribute object, what is this about? 4:13 I actually know what's up with this one but 4:19 this is a really good illustration of why you often have more problems than you 4:21 expect when you're combining class based views. 4:24 So if we look at our views.py, we see that we have a list view and creative view. 4:27 We are extending both of those. 4:32 But we're extending list view first and then we're extending create view. 4:34 This means that create view is the final class that it extends. 4:38 And anytime we've done a super, which the mixins for 4:42 class based views do supers all the time, supers work from left to right. 4:45 So the list view does all of its stuff and then the create view does it's work. 4:50 Since creative view's build process look for an object attribute and 4:53 list view doesn't create that, because it doesn't have a single object, 4:57 it has multiple objects, it doesn't exist. 5:00 The attribute doesn't exist and we get that error. 5:04 Thankfully, this exact problem has an easy solution, just reverse the order. 5:07 So, CreateView then ListView, okay? 5:15 Everything else stays exactly the same. 5:19 If I refresh this, Then I get a template error. 5:22 Cuz I forgot to close that template. 5:29 All right. 5:32 There, so now I have the field. 5:34 So I can create a new team here if I want. 5:36 I can do the Adders and they practice at the old field and 5:40 test user is their coach because I'm tired of coaching so many teams. 5:46 And then we go, we have the Adders, they have shown up. 5:50 So that's pretty awesome. 5:52 This now works because create view's get method gets fired first and 5:54 that method actually creates the blank object attribute. 5:59 Later, list view runs on its own, doesn't do anything to that object attribute and 6:01 everything's fine. 6:06 So yay for execution order. 6:07 As you might have guessed, this isn't the best way to get more custom views. 6:09 Django's class based views are mostly built up using mix-ins and 6:14 those mix-ins are available for you to use. 6:17 Take a break. 6:19 Take a walk, get a snack, tell someone they're important to you. 6:20 Then come back to the next video, where I'll walk you through using Django's 6:23 mix-ins, some third party ones and how you could even write your own. 6:26