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Logout View3:24 with Kenneth Love
Probably the simplest view we'll write for the entire app. We'll use a handy method from Flask-Login to log users out.
logout_user()- Method to remove a user's session and sign them out.
@login_required- Decorator to mark a view as requiring a user to be logged in before they can access the view.
Logging a user out doesn't require us to create a new form or anything like that. 0:00 So, we can do it all with one simple view. 0:04 Okay, so we want to be able to log users out. 0:07 This is something we're gonna, we're not gonna write the HTML for this just yet 0:11 because we're gonna do that when we build our whole layout. 0:14 But we do wanna go ahead and make a view for this. 0:19 So let's go back over here to app.py, and 0:21 we actually need to do a couple of imports. 0:24 So if we come up here to our login line 3. 0:26 So we have a login_user. 0:31 We need to import logout_user as well. 0:33 And then, because we don't want, it doesn't really matter, but 0:37 we don't want people to go to the logout view unless they're already logged in. 0:40 So, we're gonna bring in a new decorator, which is login_required. 0:44 And I can see that I'm at 82 characters, so we're gonna break this up 0:48 just cuz I'm super, super picky about this stuff. 0:53 Okay. 0:58 So there's those. 0:59 So let's go add our new view. 0:59 And,we'll put it down here after login. 1:03 And it will be app.route, logout. 1:06 And we don't need to specify any methods like get or 1:11 post because it's only gonna be through get. 1:14 And then we're gonna add a second decorator cuz we can add more than 1:16 one decorator. 1:19 And we're gonna say login_required. 1:21 So, you get to this view, you have to be logged in. 1:23 If you're not logged in, we'll send you to the login page, which is kind of 1:25 funny cuz you'll go to the log in page just so you can soon hit the logout page. 1:29 But whatever. 1:33 And we'll say def logout. 1:35 And we're gonna call logout_user. 1:37 And we're gonna call return redirect, url_for, index. 1:42 So let's talk for a second about what logout_user here and 1:48 login_user here are doing. 1:52 What are those doing? 1:55 They're creating sessions on the user's browser. 1:56 And they're giving them a cookie. 2:00 And the cookie references their user account. 2:02 And it says, hey, this user's logged in. 2:05 Now, this isn't necessarily the absolute, most secure way of doing this. 2:07 If you go look at Flask login, you'll find some other stuff that we want to do. 2:11 We might even want to start storing like sections in the database instead of 2:15 just in this cookie. 2:19 But we're making a note that they're logged in. 2:21 So now they're able to do stuff. 2:23 And we know who the user is. 2:25 So that's what login_user is doing. 2:27 logout_user deletes that cookie, gets rid of that information. 2:28 So now we no longer know who they are. 2:32 They've been kicked out. 2:35 We don't need them anymore. 2:36 So, that's a fairly nice thing to have because it gives us 2:38 a great way of handling very easily, hey, this user's in or hey, this user's out. 2:41 We don't want them anymore. 2:46 And something else we might do is we might actually add a flash here that says, 2:47 You've been logged out! 2:52 If we wanna say, Come back soon!, 2:56 just because we can. 2:58 And we'll do a success on that too. 3:00 So now when we get our Flask messages showing up all the time, then we can just 3:02 [SOUND] throw this stuff up, and it'll be a great experience for our users. 3:07 I love when things only take a couple of lines to achieve. 3:12 In our next stage, 3:16 we'll tackle the main part of our app, letting users post new status updates. 3:17 We'll need to use all of our current skills and a couple more. 3:21
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