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- [Man] Hi and welcome back to the course.

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In this video, we're going
to be creating the item list

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and also creating the
items properly this time

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using the data in the JSON payload.

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First of all, there's unfortunate chances

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that we may run into errors
throughout the course,

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and there's nothing more infuriating

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than very terrible error
messages that don't help you out.

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Fortunately, Flask has a way
of showing good error messages,

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and the only thing we have to do

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is in app.run before or after
port, it doesn't matter.

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Just type comma debug equals true.

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Now when you get on error message,

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when something really goes
wrong in your application,

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now, you'll get a nice html page

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that you can sort of visit,

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and it will tell you what's wrong.

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Also, if you ask a
question in the course Q&A,

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having that html page really helps me out

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when it comes to helping you

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debug and troubleshoot your problems.

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Okay, so the item list, that
was a challenge for this video.

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I suggested that you try this on your own.

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Hopefully, you have managed to do that,

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and it's really simple.

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Class item list is gonna
be on new resource,

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and it's going to have a get
because that's what we defined

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in the postman collection.

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We didn't pass in any parameters
in the postman collection,

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so there's not gonna be any
parameters to the method

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and all this is going to
return is a list of items,

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Is items three dictionary
of items is items.

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Items is a list which
contains all our items.

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So that's really everything.

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Don't forget to add
the resource item list,

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and make sure to give
it the correct endpoint,

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which is going to be /items.

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That's it.

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So, hopefully you managed
to do that in the challenge.

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Now we're going to go into improving

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these two methods slightly.

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The first improvement that is
going to happen in this video

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is going to be to actually
create items properly.

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Now, the first thing we
need is the JSON payload.

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We looked at this in the last section.

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How to get the JSON
payload from a request.

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Hopefully, you remember how to do that,

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and I would encourage you
to try that on your own now

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and see how far you get.

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Hopefully, you were able to do that.

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The first thing we have
to do is to go up here

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and make sure to import request.

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That is going to be when
somebody such as postman

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makes a request to our API,

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that request is in this variable.

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So, that request is going
to have a JSON payload,

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a body attached to it.

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So, we're going to say data
equals request.get JSON.

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If the request does not
attach a JSON payload

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or the request does not have
the proper content-type header,

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this will give an error, so
that's something to remember.

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And what I mean with
that if we go to postman,

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notice how we have set
the content type properly.

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If you do not do this, that
line will give you an error,

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and similarly if the body is not JSON,

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then that will also give you an error.

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For example, if you put
some python code in there.

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I don't know why you would do that

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but nevertheless and just so you know.

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In case you are not sure

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if your clients are going
to give you JSON or not,

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you can prevent this
from giving you an error.

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There are two things you
that you can pass this method

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that are really useful.

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The first one is false equals true.

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False equals true means that

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you do not need the content-type header.

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It will just look in the
content and it will format it

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even if the content type header

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is not set to be application/JSON.

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This is nice, but it's also dangerous

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because it means that without it,

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you look at the header and
if it's not set correctly,

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you just do nothing and with it,

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you don't look at the header.

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Therefore, you're always going to be doing

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the processing of the text
even if it is incorrect.

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I tend to not use false equal true.

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The other one that is
also quite handy sometimes

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is silent equals true
and what this does is

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it doesn't give an error,

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it just basically returns none.

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That okay?

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So, this another thing that
you can do if you prefer.

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Now that we've got the data
there, we can get the price.

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So, I'm sure you know how to do that.

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Data is going to be a dictionary,

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and you know how to access
data from a dictionary.

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So, it should be fairly
straightforward data price

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in square brackets and as a string

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that's going to access the price
key of the data dictionary.

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And price is here, one of
the keys of this dictionary,

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and in this case, it's
going to be equal to 12.

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Apologies, this is the
return, the return content.

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Price is a key here in the dictionary,

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and the content is going to be 15.99,

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so when we create a chair,
it will have that price.

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Okay, so let's save that.

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Go back to the terminal,
press 'control + C'

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to quit and restart the app.

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Notice how now we get slightly
more different information

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because we've enabled debug equals true.

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And then let's go over to
postman and create our chair.

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Notice how now, the price is
no longer 12, it is 15.99,

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and also notice how now we
can go to our items endpoint

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and retrieve all of the
items in our database.

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Do remember everything
you restart the app,

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this list gets cleared because
it is an in-memory database.

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It only resides in memory,
and when you stop the app,

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that memory gets cleared,

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and you could lose the whole data there.

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That's why normally,
these things are stored

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in a database which is more permanent.

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Okay, so that's really it for this video.

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In the next video, we're going to improve

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on the iteration here by
using a filter function.

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We've looked at those
in the Python refresher.

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Now may be a good time

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to look at the Lambda Functions lecture

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in the Python refresher if
you haven't done so before,

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and because in the next video,

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we're going to use a lambda function.

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That's it for this video though,

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thanks for watching, and I'll
see you in the very next one.