Name: CS50 2018 - 再生7 - Webプログラミング (CS50 2018 - Lecture 7 - Web Programming)
Uploaded: 2021-01-14T10:28:36.000Z
Duration: 1 h 51 min 46 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

This CS50 and this is lecture 7 wherein we pick up

where we left off last time in talking more about Python,

but this time using Python for even more powerful purposes,

an alliteration I didn't intend until I just said it there.

But the goal here with Python now is to actually use

this language to generate another language, in particular HTML.

And what we'll do is start to provide all the more of a mental model

for what you would call separation of concerns, whereby

when you design more complicated web based, or rather when you design

more complicated software, you tend to try to adopt certain design patterns so

that you're not just writing everything in one big file that

gets a little confusing, unwieldy to maintain and to add to over time.

But you start to separate your concerns, and your functionality,

and your features, and your collaborators' work

into different files and different methodologies.

So we'll try to give you some of these industry standard approaches today

A few weeks ago, we talked about this thing,

this virtual envelope that just represents

packets of information, zeros and ones, going across the internet from point A

to point B. And among the messages in these envelopes

And we talked about HTTP, a protocol, hypertext transfer protocol,

that just sends message like this inside of the envelope.

And this is requesting, of course, the default page

And in many cases, but not always, this implies

But that's a human convention, not a requirement.

Hopefully, the server responds with a numeric code equal to what integer?

200, hopefully, a number that we never actually

really see unless you get more comfortable

and start poking around Chrome's inspector

So here is an actual successful response,

And if the browser looks a little farther down in the virtual envelope,

if you will, it will see another language called HTML, HyperText Markup

Language, which is the stuff we wrote a couple of weeks ago

and you'll continue writing this week as you now dynamically generate websites.

But what we'll introduce today is what's also known as a framework,

or, more precisely, a microframework, because we'll see in just a few minutes

time that it can actually be really annoying and really tedious

to generate websites automatically using Python

And so humans, over the past several years,

have noticed, wow, every time I make a web application using Python,

I find myself typing the same lines of code

again and again just to get started, or when I'm collaborating with someone

else, I find that, ooh, it's a little hard to collaborate

So humans have invented what are called frameworks.

And this is an example of code written in Python

So whereas Bootstrap, which you've played with a little bit,

is a framework for CSS and JavaScript, they have some dynamic features

as well, Flask is a framework for Python that

just gives you some library code that you can use freely

And it just makes it, ultimately, a little easier to get your work done

and build the thing you want to build as opposed

to having to reinvent the wheel again and again like people before you.

And so here is a methodology to which I alluded earlier just to have

So up until now, pretty much every program

we've written in C and most recently in Python

you could call like controller code or controller logic or business logic.

It's all about getting something done logically,

usually in one file, maybe two files if you have another helpers.ce or header

But today and two weeks ago when we will focus

on web programming in HTML and CSS, there's the second part of our world.

There's like the logic that gets the interesting work done with loops,

But there's also now going to be the aesthetics,

the stuff that the user actually sees and the way you present your data.

So we're going to just introduce two letters of an acronym

Anytime you start writing logical code in Python,

It's sort of like the machine that operates your entire web application,

but anytime you do something more aesthetic,

we're going to call that your view code, so C and V being the letters here.

And this just refers to a separation of concerns.

And your aesthetics and formatting go in this other file.

Next week, we'll introduce databases in SQL, structured query language.

And we'll introduce an M here, because the acronym that's

in vogue for quite some time now is MVC, though there

And that just means there are three different types

of things you should be thinking about when building an application.

But today we're going to focus on these two, controller and view.

And up until now, we've pretty much been doing entirely controller stuff

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CS50 2018 - 再生7 - Webプログラミング (CS50 2018 - Lecture 7 - Web Programming)

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