Sifat permintaan HTTP

Web Scraping di R

Timo Grossenbacher

Instructor

Hypertext Transfer Protocol (HTTP)

Skema yang menunjukkan bagaimana browser berkomunikasi dengan server

¹ https://developer.mozilla.org/en-US/docs/Web/HTTP/Overview

Anatomi request

Sebuah request dikirimkan ke server web

Contoh request

Kode status umum: 200 (OK), 404 (NOT FOUND), 3xx (pengalihan), 5xx (galat server)

Sebuah response diterima dari server web

Response yang sesuai

¹ https://developer.mozilla.org/en-US/docs/Web/HTTP/Overview

Metode request: GET dan POST

GET: Mengambil resource tanpa mengirim data (GET /index.html)
POST: Mengirim data ke server, mis. setelah mengisi formulir di halaman

POST /test HTTP/1.1
Host: foo.example
Content-Type: application/x-www-form-urlencoded
Content-Length: 27

field1=value1&field2=value2

Request POST juga dijawab dengan response!

¹ https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST

Permintaan HTTP dengan httr

library(httr)
GET('https://httpbin.org')

Response [https://httpbin.org/]
  Date: 2020-09-19 13:02
  Status: 200
  Content-Type: text/html; charset=utf-8
  Size: 9.59 kB
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    ...

Permintaan HTTP dengan httr

library(httr)
response <- GET('https://httpbin.org')
content(response)

{html_document}
<html lang="en">
[1] <head>\n<meta http-equiv="Content-Type" content="text/html; charset=UTF ...
[2] <body>\n    <a href="https://github.com/requests/httpbin" class="github ...

Ayo berlatih!

Web Scraping di R