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Since Flask is a microframework,
it often gets used as a single module or

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maybe a model or two and then all of the
routes and logic in a single app module.

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This works great until your app
gets moderately complex and

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you start having to use your editor search
function just to find a particular piece.

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Once you split everything
out into separate files,

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you'll likely find that it gets harder and
harder to avoid circular imports.

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Or a chain of imports that ends up
having one file import another file that

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also imports the first one.

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Flask has a feature named Blueprints, and

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Blueprints give us the ability to make
objects that are almost like proxies for

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Flask apps or
other features like our API resources.

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Let's hop back into work spaces and
get this all wired up with Blueprints.

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Okay so I need to import
the Blueprint object from Flask.

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I'm here inside courses.py and so
I'm just gonna add Blueprint right there.

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Now this might seem a little bit weird and
awkward but just stick with me for

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a minute.

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So I'm gonna to make a blueprint that
represents this entire module course.py.

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I'm wanna do this down here at the bottom.

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And I'm gonna say courses_api = Blueprint

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('resources.courses'), which
is the path to the file and

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then name which is
the namespace that we're in.

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So it's the file all over again.

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So basically this says, okay,
treat this file with this namespace and

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this path as being another app,
another thing.

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And like it's a proxy to this module
that kind of sort of acts like an app.

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It's not an application, this isn't
a pluggable app or anything like that.

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It actually kind of acts
like a log to some degree.

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Anything that I do to this,

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all the actions that I execute on
the blueprint, don't actually happen

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until I register the blueprint
with an actual running Flask app.

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I'll show you what I
mean with this next step.

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We've got to add a little bit
more to this file though.

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So we have to actually make an API.

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And it's weird that the import is capital
A lowercase pi, but just whatever.

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Okay, so then we're gonna
say api = Api(courses_api).

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So we're making an API out of the current
module, which kind of acts like an app.

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Normally you pass in an app here,
okay, you with me so far?

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All right, let's do the next thing here so
api.add_resource.

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And resource we're going
to add is CourseList.

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And we're going to set the endpoint
to be /api/v1/courses,

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or this is the URL slug rather, and

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then the endpoint we're actually
going to call this is courses.

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Okay, and then we're gonna add
another one here, api.add_resource.

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And this one goes to Course, and

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again we're going to
give it /api/v1/courses.

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And then we're going to say that there's
an int argument that we're gonna call id.

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And then this endpoint
is going to be course.

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All right.

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So each of these specifies
the resource to add, like CourseList.

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The URI to give to that resource.

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And then the endpoint to name it.

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This way we can be like,
I want the courses endpoint.

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Now you don't have to
provide the endpoint name,

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Flask just lower cases
the name of the resource.

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So like this one would become course
list and this one would become course.

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You'll probably find yourself
wanting simpler import names,

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you don't necessarily want course
list as the endpoint name.

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And the name can be used a few
different places in Flask RESTful.

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Some of those,
we're gonna talk about a little bit later.

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Okay so now I have to register
the endpoint with the app, so

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I'm going to pop back over here to app.py.

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And up here after I import models
I'm gonna say from resources.courses

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import course_api.

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And then after the app thing
here I'm gonna do app.register

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_blueprint (course_api).

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All right, so, courses_api,
and courses_api.

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There we go, okay.

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So I should be able to
get a list of my courses.

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So if I go to /api/v1/courses, cool.

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There's my courses and
my fake course that's in there.

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All right, so that's awesome.

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There it is.

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Now I'm enforcing the API versioning, the
versioning number right here in the URL.

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Right that's what I have the /v1.

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This is pretty common and
it's probably the easiest solution.

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This is probably what you'll find
yourself doing most of the time.

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And this way you're keeping the resource
and the API right next to each other.

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But you can also do this in the blueprint.

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I kinda like that solution
a little bit better too.

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It feels a little bit cleaner.

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Let me show you that one for reviews, and

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you can decide which one
that you like better.

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So up here at the top,
we're gonna import Blueprint.

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And we're gonna import API
just like we did before.

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And then down here, reviews_api=Blueprint(

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'resources.reviews, __name__),

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api= Api(reviews_api).

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api.add_resource, and ReviewList and

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I'm just gonna put in /reviews.

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And my endpoint is gonna be reviews.

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And then api.add_resource.

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Review, and here I'm gonna put reviews.

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And then of course again my int:id
argument and endpoint = review.

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All right.

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So I didn't put any of
the versioning numbers in here.

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So I'm gonna come back
over here to app.py and

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from resources.reviews import reviews_api.

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And then here,
app.register_blueprint(reviews_api),

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just like before.

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And then we're gonna do
this url_prefix='/api/v1').

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And so this does the same work, but
we're doing it where we register

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the blueprint instead of
where we create the resource.

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So it's kind of six of one
half a dozen of the other.

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So if we go here to reviews,
then we get our reviews.

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Now have the same URL pattern,

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but I've defined them in two different
ways in two different places.

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Like I said you can pick whichever one of
these URI methods that you like better.

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I'll leave them both implemented
throughout the course though, so

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that you can see them both multiple times.

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Blueprints actually took me
quite a while to figure out.

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They're not 100% intuitive, but once you
get the basic ideas of them down you'll be

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able to use them to make your Flask
projects cleaner and better organized.

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They open up a whole new world
of Flask project design.