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title logoImg theme transition highlightTheme slideNumber loop autoSlide enableMenu enableChalkboard autoSlideStoppable
HTTP with Node
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<style> /* Remove the background color and make mongo commands more visible by adding color */ .line.focus{background:none;font-size: xx-large;color: #5cc4ea;} </style>

What is HTTP?

HyperText Transfer Protocol

  • Used to send text-based files such as HTML, CSS, etc.
  • Read about it on wiki.

--

How HTTP Protocol works

The communication protocol between clients and servers.

Read the official MDN docs about it {.fragment }

HTTP Protocol

:::block Browser makes a ...{.fragment }

Request to the ... { .fragment }

{style=width:50%;float:left; height:50%} :::

:::block Server which then sends a ...{ .fragment }

Response ... back to the client{ .fragment }

{style=width:50%;float:right; height:50%} :::

--

Client Request

When we hit enter on a URL .. {.fragment}

HTTP Protocol

The client (browser) makes an HTTP request to GET the website's resources, such as HTML, CSS, JavaScript, images, etc... {.fragment}

--

Server Response

This where the server, responds to the request and sends them the resource they want to get such as a text file such as HTML, CSS, or even images. {.fragment }

HTTP Protocol

The browser then reads that file and presents it to the user according the specified Content-Type, such as text/html. {.fragment }

--

HTTP Status Codes with CATS..

Credit to http.cat.

:::block

HTTP Protocol

{style=width:60%;float:left;} :::

:::block 1xx codes are informational ...{ .fragment }

2xx ... sucesses ! 🎉 { .fragment }

3xx ... redirection... { .fragment }

4xx ... client error...{ .fragment }

5xx ... server error...{ .fragment }

{style=width:40%;float:right;} :::

--

HTTP VERBS

GET refers to requests made to read data. {.fragment }

POST refers to requests made to create data on a server. {.fragment }

UPDATE refers to requests made to update data. {.fragment }

DELETE refers to requests made to deletes data. {.fragment }

Exercise 1: Your first HTML file...

Inside 0-student_files/index.html type the following HTML.

--

What is HTML?

  • Stands for Hyper Text Markup Language
  • It is NOT a programming language
<!DOCTYPE html>
<html lang="en">
  <head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style> /*Inline Styles Go Here*/ </style>
  <link rel="stylesheet" href="./style.css">
  <!-- HTML COMMENT -->
  <script src="./script.js"></script>
  <title>HTTP with Node</title>
  <!-- <link rel="icon" type="image/png" href="images/favicons/favicon.png"> -->
  </head>
  <body>
    <h1 style="text-align:center">Hello World</h1>
    <p>
      Here is a hyperlink to
       <a href="http://google.com">
       Google
       </a>
    </p>
  </body>
</html>

This defines the doument type as html. {.fragment .current-only data-code-focus=1-1}

Start the HTML tag and define the language {.fragment .current-only data-code-focus=2-2}

Close the html tage with </ html> {.fragment .current-only data-code-focus=22-22}

Start the <head> tag which contains everthing to be preloaded before the page. {.fragment .current-only data-code-focus=3-3}

This can include things like the meta tag. {.fragment .current-only data-code-focus=4-4}

Notice that it is self-closing? <meta /> {.fragment .current-only data-code-focus=4-4}

This is for responsive websites. {.fragment .current-only data-code-focus=5-5}

This is for inline CSS {.fragment .current-only data-code-focus=6-6}

This is for linked CSS {.fragment .current-only data-code-focus=7-7}

This is an html comment and it does not render for the user. {.fragment .current-only data-code-focus=8-8}

Looks like the following: {.fragment .current-only data-code-focus=10-10}

You can change that global icon to a custom "favicon" by updating the meta tag {.fragment .current-only data-code-focus=11-11}

Now we close </head> tag by adding the back /. {.fragment .current-only data-code-focus=12-12}

Inside the <body> tag is our website content. {.fragment .current-only data-code-focus=13-21}

The <a> tag is for hyper links. {.fragment .current-only data-code-focus=17-19}

The URL goes in href=" " . {.fragment .current-only data-code-focus=17-17}

The Text goes between the tags: <a> text </a> . {.fragment .current-only data-code-focus=18-18}

This goes back to Hyper Text Transfer Protocol (HTTP) {.fragment .current-only data-code-focus=17-17}

Congrats! 🎉🎉🎉🎉 You should now know enough HTML to get by with the rest of this lesson... {.fragment .current-only}

Node.js is ...

NOT server! {.fragment .current-only }

It is JavaScript RUNTIME Environment! {.fragment .current-only }

It has an HTTP method as part of it's core API that allows it to be used on servers such as... {.fragment}

  • Apache {.fragment}
  • NGIX {.fragment}
  • etc {.fragment}

Exercise 2:

Sending HTML with HTTP

Step 1: Create a file called simpleHTTP.js { .fragment .current-only}

Now, we'll use node.js's built-in API http method to handle the requests and the response data. { .fragment .current-only}

Step 2: Type the following code into simpleHTTP.js { .fragment .current-only}

--

const http = require('http')
const fs = require('fs');
const PORT = 7000;
http.createServer(function (request, response) {
  if (request.url == '/') {
    fs.readFile('index.html', function(err, data) {
      response.writeHead(200, {'Content-Type': 'text/html'});
      response.write(data);
      return response.end();
    });
  }
  else{
    return response.end('Invalid request');
  }
}).listen(PORT);

Import / require node.js API Modules. { .fragment .current-only data-code-focus=1-2}

This module creates the connection to our server and uses the http protocol. {.fragment .current-only data-code-focus=1-1}

This module is used to read files. {.fragment .current-only data-code-focus=2-2}

Creates a server and consumes port 7000. {.fragment .current-only data-code-focus=3-15}

If the request is localhost:7000/, then return a response with index.html {.fragment .current-only data-code-focus=5-11}

ELSE KILL the server, then return invalid response {.fragment .current-only data-code-focus=12-14}

Uses FS to read the the html file. {.fragment .current-only data-code-focus=6-6}

Inside the callback, define the correct HTTP header with the correct content type. {.fragment .current-only data-code-focus=7-7}

Exercise 3:

Dynamic Sites without Expess.js

  • Believe it or not, you don't need EJS in 2020...
  • You may also not even need react... 😲

Create a function that returns HTML

:::block

  • Using Template Strings as a template engine...
  • Simple enough to teach.
  • Not secure enough for sales...

{.fragment .current-only} :::

const HtmlTemplateString = (header,body,footer) => {
  return `
  <!DOCTYPE html>
  <html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    ${header}
  </head>
  <body>
  ${body}
  ${footer}
  </body>
  </html>`;
}

This function has 3 parameters, a header, a body and footer. {.fragment .current-only data-code-focus=1-1}

We can use this to pass in stylesheets, scripts, meta attributes, etc. {.fragment .current-only data-code-focus=8-8}

Here we pass in out page content. {.fragment .current-only data-code-focus=11-11}

Here we can include any copyrights, scripts, etc . {.fragment .current-only data-code-focus=12-12}

Using HtmlTemplateString() to create a layout

const http = require('http')
const fs = require('fs');
const PORT = 7000;

const HtmlTemplateString = (header,body,footer) => {/* Code from above */}
let page1 =HtmlTemplateString(
  `<title>Hello</title>`,
  `<h1>Hello World END</h1>
  <div>Content about the world</div>`,
  `<footer> By Hans </footer>`)

http.createServer(
  (request,res)=>{
    if (request.url == '/') {
      res.writeHead(200, {
        'Content-Type': 'text/html',
        'Content-Length': page1.length,
        'Expires': new Date().toUTCString()
      })
      res.end(page1);
    }
  }
).listen(PORT);

Store the final result of the HTML layout as string assigned to page1. {.fragment .current-only data-code-focus=6-10}

The header should have a title of "Hello". {.fragment .current-only data-code-focus=7-7}

The body should should say "Hello". {.fragment .current-only data-code-focus=8-9}

The footer should should say "By" and your name and wrapped in a <footer> tag. {.fragment .current-only data-code-focus=10-10}

Set the page content-length. {.fragment .current-only data-code-focus=17-17}

Send it. {.fragment .current-only data-code-focus=20-20}

HTTP With JavaScript ES6

const http = require('http')
const fs = require('fs');
const PORT = 7000;

const HtmlTemplateString = (header,body,footer) => {/* Code from above */}
let page1 =HtmlTemplateString(/* Same Code from above */)

  http.createServer(
    (request,res)=>{
      if (request.url == '/') {
        res.writeHead(200, {
          'Content-Type': 'text/html',
          'Content-Length': page1.length,
          'Expires': new Date().toUTCString()
        })
        res.end(page1);
      }
    }
  ).listen(PORT);

Thank You for reading...

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