Building Data-Driven Web Apps with Flask and SQLAlchemy Transcripts
Chapter: User input and HTML forms
Lecture: Navigation items based on user's session
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I'm actually logged in, can you tell?
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Of course you can tell, it says login and register.
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Normal science once you're logged in
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it says here's your account, logout, sign out
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something like that.
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But you can tell that I actually am logged in if I go here.
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So, what gives?
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Well, we need to control this navigation based
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on whether or not we're logged in
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and luckily we have one and only place we got to do that
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over in our little shared layout here.
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So, up here we have these bits
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that have to do with navigation
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and account and so on
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and so, let's go actually over here
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and let's say if user_id and if.
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Okay, these all look pretty good
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and up here we want to have
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if you have a user_id
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it's going to have your account.
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I also have a logout.
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And that'll just be /logout.
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All right, so theoretically this'll work.
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Let's refresh it and see.
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Now why is this not changing?
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It's not changing because here's the bad part
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every single view method
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has to send the user_id across.
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Super annoying.
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What we're going to see in the next chapter
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is some really awesome patterns
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that will make this go away.
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Let me fix it the hard way now.
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We'll see that it works
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and then we'll refactor it to a pattern
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that you can just appreciate more
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because it also solves this problem.
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So, what we got to do
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is all the places, when I go in here
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let's just work on the home, for example
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down here in the views.
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In addition to all this stuff
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we have to set user_id
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to be cookie auth.
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Get user and I say flask.request, lowercase request.
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Like so, so we got to put that everywhere.
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We got to put it here, we got to put it into about
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and there's no need for you to watch me write this
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a bunch of times.
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So, I'm going to go do that on every single view method
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and then we'll come back.
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All right, I put it in every single view method
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and I'm going to refresh this page.
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Now every view method passes back the _user_id
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if it's there and none if it's not.
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So, let's refresh the page and see what happens.
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Whoa, account, all right.
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Awesome, account is there, welcome to your account, Michael.
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I can go all over, I come over here
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even go to one of the packages
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you can see account and log out
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so we can go to our account
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and if I logout, I'm now logged out
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I can still cruise around the site
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can see this is keeping track of what I'm doing, right?
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If I try to go to account
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still it's going to redirect me.
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Right, so that's working super well.
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It was actually really easy to do
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just tiresome that we got to put it everywhere
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and if it's not there
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then that page will just basically think we're logged out.
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Like I said, we're going to work
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on a pattern called view models
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that just completely solves this problem
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for the entire site.
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For now, I've got to do this more manual
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but you can see it's not super hard, right?
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I log in.
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Boom, navigation changes right up there across the site.
