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Cookies
7:27No, not the kind you dunk in milk. Browser cookies are little bits of data that your browser lets sites store on your computer. We'll use them to store all of the user's choices for their bear. Let's see how to store information in a cookie for later retrieval.
Cookies, aside from being delicious,
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are a very common way of storing data
between requests.
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We're going to use them to store the
information that our users submit
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through the form.
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That way we can preserve their character
for them to get on future visits.
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To do that, we're going to turn the form
submissions into JSON.
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This should be a particularly exciting
section.
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So, first things first let's try and get
the data saved into the cookie.
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When we looked into our request object in
the last video with PEB, we saw that
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the request.form object was this [UNKNOWN]
like thing that has all of our value,
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all of our data in it.
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So thankfully, dictionaries turn into JSON
very smoothly.
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So let's start there.
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So the first thing that I need is I need
the JSON library.
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And this is just built into Python, it
works, it's, it's pretty amazing.
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So now, down here in our save view, we
need to set the cookie.
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So setting cookies in flask is a little
bit weird especially if
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you have worked with like Jango or just
JavaScript in general.
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Normally you just like set a cookie so,
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in Flask though cookies are set on the
response.
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The thing that goes back to the browser.
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But we don't have that until after this
return fires.
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The return, like, generates the response.
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So, we have to kind of fake this response.
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So, we need to add another import.
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So, we're gonna say, Make Response.
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And if I look down here, this says 84.
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That means I've gone way too long.
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So, I'm actually gonna go ahead and
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just split this, just about there, that
looks cool.
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This is a nice way to build the multiple
imports like that if you really want to.
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I just don't wanna go over a bunch of
lines.
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So what I'm gonna do is I get down here
and I'm gonna return,
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I'm gonna do two steps to make my response
and then return my response.
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So, I'm gonna do response, if I could
spell it right.
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Equals make response and then I'm going to
pass in the redirect URL four index.
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And then, down here,
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instead of returning the redirect, I'm
going to return the response.
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Okay?
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So let's make sure this still works lets
build it.
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Comes right back, cool, so still working.
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So now, I want to actually set the cookie.
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So I'm gonna do response.setcookie and I'm
gonna call the cookie character.
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Or we can call it bare we can call it
whatever.
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And were gonna do json.dumps the
dictionary
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form a request.form.items.
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And the reason we have to do the dict
casting there, is because what
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comes out of request.form isn't exactly a
dictionary, it's this immutable dict.
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Immutable multidict when we call items, it
gives us back a tuple of key-value pairs.
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So we call dict in order to create a
dictionary from that and
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then we bump that into jason.jumps.
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We've given the cookie a name character
and then we fill in that value.
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So the only other thing that's new here is
json.dumps.
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And, it's actually dump s for dump string.
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but, you know, you're just gonna say
dumps, right?
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So, if we submit the form again, we should
be able to see the cookie in the browser.
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So, Mike.
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And then let's look at our inspector here.
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And if we look at resources, we see
there's this cookie.
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And I've got a cookie called Character,
and it has a value name, or
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its value has a dictionary in it with a
key of M and a value of Mike.
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So, let's see about getting that back out.
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We wanna do that in our index view, but
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I have a feeling we're gonna need to use
this elsewhere.
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So let's make a new function, actually.
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So we'll say get_saved_data, and we'll do
a try and we'll say
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data equals json.load, loads, or load s.
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Load string.
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And we wanna do cookies.get character.
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If we had named it differently down below
we'd change that name here obviously.
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Except type error.
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So if the cookie gives us something we
can't turn into JSON.
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We're gonna get type error.
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And, we'll say data is equal to just an
empty dictionary,
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and we wanna return that data.
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All right.
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So, JSON dumps creates JSON, creates a
JSON string.
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And, loads, takes that string and
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turns it into Python code again, so it
turns data it makes data a dictionary.
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All right so that's pretty cool.
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If nothing, if it doesn't work, we get
this empty dictionary.
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Let's go down here to index and what we
wanna do here is,
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we wanna do, we'll call this saves, and
we're gonna pass in data.
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Okay.
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And, you know, something else that I know
is gonna come up and
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is gonna work wrong, is we're gonna end up
coming down here and
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we're gonna end up just completely
obliterating some stuff.
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So let's make sure that we're updating
things.
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Let's do data equals get_saved_data.
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And then let's do data dot update dig
request.form.items.
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And then we're gonna set json.dumps of
data.
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So what we're doing is we're saying, okay
hey you've got,
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you've got this information that's already
stored and what we should do is
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we're gonna update it, if anything has
changed, and then send that back.
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Save that new one.
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Okay, so we've saved this information.
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Let's let's print that out.
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Okay?
So let's go back over here to our,
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our thing.
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And we've got this, this thing here,
right?
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Let's put into this value.
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Let's print out.
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Saves name.
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Actually, let's do saves.getname.
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And then an empty string.
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So what happens here is we try to get the
name key,
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if the name key doesn't exist, then we get
this empty string.
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Okay, so that's pretty cool.
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So save that, run the app.
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The preview does not work.
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Let's try that preview again.
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All right.
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Data is not defined.
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Because we forgot to get data out of here.
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So we'll do data equals get_saved_data.
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All right, refresh, and hey, here's our
name, it says Mike already.
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So that's pretty cool.
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Using cookies is a great way to hold on to
data.
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Especially when we're not using a
database, and
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don't want to have to use JavaScript for
something like local storage.
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