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You have completed Flask with SQLAlchemy Basics!
You have completed Flask with SQLAlchemy Basics!
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Start creating a basic website using Flask.
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Are you ready to jump
into the world of flask?
0:00
Let's start with importing flask.
0:03
From lowercase f,
import flask with an uppercase F.
0:06
To start our site, we'll need to
create a new variable called app,
0:14
and set it equal to Flask and
pass in Dunder name.
0:19
Dunder name refers to
the namespace this is running in,
0:25
we will be running this
in app.py directly.
0:29
So the namespace will be Dunder main.
0:33
If we were to import this
file to be used elsewhere,
0:36
it would take on the name of
the file it is located in.
0:39
In this case, app for app.py.
0:43
Now that we've created our app,
let's create our first route.
0:48
A route from the user side is just
like a URL, like teamtreehouse.com.
0:52
From the application side, a route is
a command to run a specific function,
0:58
which then returns
the response to the user.
1:02
To create one,
we'll have to use a decorator.
1:06
It looks like this.
1:09
@app.route, and
we're gonna give it a slash.
1:11
In simple terms,
decorators are functions that wrap around
1:18
other functions and
let you do things with them.
1:23
Next, we'll define
a function called index.
1:28
This is the function our
decorator wraps around.
1:38
Index is the typical name used for
the homepage.
1:42
And it's a pattern you'll see a lot.
1:46
Inside this function,
we'll return a string
1:47
that says, Hello from Pet Adoption.
1:53
Here, the app.route function works as
a part of the request response cycle.
1:57
When someone requests our apps homepage or
2:06
the root route,
this decorator will call our function,
2:11
which will then send
a response of our string.
2:17
Now before we run this,
we need to tell the app to well run.
2:23
I'm going to place this inside of
a Dunder main at the bottom here.
2:29
We're going to use our app
variable to call the run method.
2:44
This method is going to
take a few parameters.
2:49
First, we're going to set debug to true.
2:52
This will restart our server
every time we change our code,
2:59
which is a nice little feature
that saves us some time.
3:02
Next, we're going to give it a port and
a host.
3:07
This is like the address
the website will be working on.
3:10
We're going to use a port of 8000,
and a host for
3:14
those working locally of 127.0.0.1.
3:20
If you're working in workspaces,
then this needs to be all zeros like this.
3:26
Since I'm working locally,
I'm gonna save my file with the 127.0.0.1.
3:32
Run the file python3 app.py.
3:40
Again, if you're on Windows or
in workspaces,
3:42
you may not need this 3 here and run it.
3:46
And you can either type in this
address here into your browser like
3:48
Google Chrome or Firefox,
whatever you want to use.
3:53
Or if you have the option,
you can do a command click or
3:56
control click if you're on Windows,
to automatically open this up.
4:00
Now if you're working in workspaces,
4:08
you'll need to click on this little
eye up here in the top right corner.
4:10
Click on the matching port and
this will open up your website.
4:14
And awesome,
our message is being sent to the user.
4:25
It seems like magic, right?
4:30
Well, maybe not so much anymore,
4:32
especially now that you
know how this works.
4:34
But it can still feel like it sometimes.
4:36
This works because you've just
made the first request response.
4:39
By navigating to the matching address,
4:43
you've requested the homepage
route from our application.
4:46
And it sent back the response, which
is our Hello from Pet Adoption string.
4:51
This all happens in
a matter of milliseconds.
4:59
Nice work.
5:03
Now, I challenge you to create
another route on your own.
5:04
You've got all the tools
here that you need.
5:09
It should have a different
location from the homepage,
5:12
but it should still start with the slash.
5:16
The function you create should
also have a unique name,
5:19
try to name it something
that matches the page.
5:22
This is the pattern you'll want
to work with moving forward.
5:26
Pause me and give it a go.
5:30
I made a cat route and sent back meow.
5:34
In the browser,
I can see this by calling that route/meow.
5:39
And there it is.
5:45
Check the teacher's notes for more
information on decorators and namespace,
5:50
if you would like to dive
deeper into those topics.
5:55
If you're saving your
work in a GitHub repo,
5:58
now would be a good time to add,
commit and push your work.
6:01
Before you leave, let's
check out Flask's documentation.
6:05
On their website, they have a quickstart.
6:10
You'll notice their quickstart code
looks a lot like what we've created.
6:13
Many popular frameworks and
6:18
libraries include quickstarts to
help show you how to get started.
6:19
There's some excellent information here.
6:23
So, take some time to read or
scan through it.
6:26
Don't worry about needing to
understand every detail of the page.
6:30
We're just getting started.
6:34
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