Scraping with R: An Overview

https://drive.google.com/open?id=1DCveWYpwlR4xfbySKVoikgdme5W71Pp57vyxSojr7XE

Open data

• An url to an dataset: https://tcgbusfs.blob.core.windows.net/blobyoubike/YouBikeTP.gz

What is web API

• 系統方將資料庫查詢轉變為一具有參數的網址，或者說，系統方提供一帶參數的網址，讓他自己或者第三方開發者可以從前端便於查詢該資料庫。

  • 情況一：使用者方透過模仿系統從前端獲取後端資料的方法來獲取資料

  • 情況二：系統方透過申請核可和發給Token來提供使用者申請使用其獲取資料方法

Rundown

Overview

1. What is Crawler?

   1. slide: Crawler designs: Request and response

   2. Types of Web response: An overview

2. Getting JSON from the Web

   1. Seeking the URL

   2. Reading data: Dcard, cnyes.com

3. Getting HTML from the web

   1. Seeking the URL

   2. Seeking the data node

   3. Parsing HTML: PTT

Types

JSON as responses

System services provide APIs for 3-party usage

• facebook ads library API, https://www.facebook.com/ads/library/api
• Twitter API, https://developer.twitter.com/
• Instagram API

• Rate limitations, the next page data

System services didn’t provide official APIs but use AJAX and API for getting data from back-end database

• 104.com

• Shinyi.com

• cnyes.com

• pchome search

• DCard

• rent591.com

HTML as responses

• PTTs

• Books.com

• ltn.com.tw

• udn.com.tw

• ibon address