Building Data-Driven Web Apps with Pyramid and SQLAlchemy Transcripts
Chapter: Introducing the Pyramid framework
Lecture: Building block: Views
Login or
purchase this course
to watch this video and the rest of the course contents.
0:00
So, let's dig into these building blocks.
0:02
First of all, we have our views or controllers.
0:06
So, what does that look like?
0:07
Well, we start by importing the necessary decorator,
0:11
from Pyramids, so from pyramid.view import view_config,
0:15
and then we just define a function.
0:17
The name of the function doesn't actually matter,
0:20
in this case, and then we're going
0:22
to map... a route... to that view.
0:26
In order to make a regular function
0:29
become one of these controller functions, or actions,
0:32
what we're going to have to do is
0:33
we put this @view_config decorator.
0:36
Usually what you'll find is there's at least
0:38
two values you set, sometimes it can be omitted,
0:41
sometimes there's more, we'll talk about that...
0:44
Is we're going to set the route name.
0:46
This is what URL maps to this function, it's a route name.
0:51
And then the template that we're going to use
0:54
to generate the dynamic HTML, so that's the renderer,
0:57
we're going to use mytemplate.pt right now.
1:00
And then this method always takes a request object.
1:04
Which is one parameter request, and that's the way it works.
1:07
The request carries with it things like the data passed,
1:10
and the URL, the form post, all that kind of stuff.
1:13
It's sort of the jumping off point to get the data out of
1:16
all the inbound stuff, and things like cookies, and so on.
1:20
We're going to take that data, do whatever it is we got to do,
1:23
maybe check for an account,
1:24
maybe pull some stuff from the database, things like that.
1:27
And then when we're ready we're going to
1:28
return our model to the template.
1:31
We do this by returning our model as a dictionary
1:34
and the framework is going to manage getting that
1:37
moved over to the template and rendered dynamically
1:40
and responded back as HTML to the browser.
1:45
This is about as simple as things get, with views right?
1:49
All we do is we have a function,
1:50
it returns a static dictionary.
1:52
Let's look at a more realistic one.
1:55
Over here, we have one and we're saying
1:57
this actually only responds to POST messages.
2:02
We're going to reset password and maybe there's one that
2:04
generates the form but this one is going to do
2:06
the password reset when they submit that form, okay?
2:10
And first of all we're going to get the data
2:13
that they put into the form, right?
2:14
What is your email that you're going
2:16
to reset your password to when they click the button?
2:19
All that data from the form
2:21
ends up in a dictionary called POST.
2:23
Alright, we're going to grab that out...
2:26
And then we're going to try to create
2:27
a password reset using our data access layer.
2:31
That may or may not work, but if it doesn't work,
2:33
then we're going to send them an error saying,
2:35
"No no, sorry that didn't work,"
2:37
and we're going to render the reset password again,
2:40
but this time the error message will be shown.
2:43
And if it does work then we're going to say,
2:46
"Alright well it looks like that worked,"
2:47
so send them a message that says,
2:49
"Check your email for the reset code."
2:52
Presumably that repository thing actually sent the email.
2:54
Not sure that's a great pattern
2:56
but it fits on one slide, so that's why it looks like that.
2:59
Alright, the idea is we call that function,
3:01
and either it did not send the password or send the email,
3:04
or if it did it saved it in the database, sent the email,
3:07
and now they just got to go check their email.
3:09
Alright this is a more realistic type
3:11
of view here processing a form POST.
