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rvestvsgot

MIT 17 1 1,455
629.3 thousand (month) Nov 22 2014 1.0.4(1 year, 7 months ago)
13,904 10 108 MIT
14.2.1(30 days ago) Mar 27 2014 88.1 million (month)

rvest is a popular R library for web scraping and parsing HTML and XML documents. It is built on top of the xml2 and httr libraries and provides a simple and consistent API for interacting with web pages.

One of the main advantages of using rvest is its simplicity and ease of use. It provides a number of functions that make it easy to extract information from web pages, even for those who are not familiar with web scraping. The html_nodes and html_node functions allow you to select elements from an HTML document using CSS selectors, similar to how you would select elements in JavaScript.

rvest also provides functions for interacting with forms, including html_form, set_values, and submit_form functions. These functions make it easy to navigate through forms and submit data to the server, which can be useful when scraping sites that require authentication or when interacting with dynamic web pages.

rvest also provides functions for parsing XML documents. It includes xml_nodes and xml_node functions, which also use CSS selectors to select elements from an XML document, as well as xml_attrs and xml_attr functions to extract attributes from elements.

Another advantage of rvest is that it provides a way to handle cookies, so you can keep the session alive while scraping a website, and also you can handle redirections with handle_redirects

Got is a lightweight and powerful HTTP client for Node.js. It is built on top of the http and https modules and provides a simple, consistent API for making HTTP requests.

Got is one of the most feature-rich http clients in NodeJS ecosystem offering http2, proxy and asynchronous support making it ideal for web scraping.

Got also supports many specific domain integrations like AWS, plugins for various public APIs like github.

Note that Got has some inconsistent behaviors when it comes to web scraping use.
For example, it normalizes http headers which is undesired functionality in scraping and should be disabled.

Highlights


http2asyncpopularextendibletypescriptproxy

Example Use


library("rvest")

# Rvest can use basic HTTP client to download remote HTML:
tree <- read_html("http://webscraping.fyi/lib/r/rvest")
# or read from string:
tree <- read_html('
<div class="products">
  <a href="/product/1">Cat Food</a>
  <a href="/product/2">Dog Food</a>
</div>
')

# to parse HTML trees with rvest we use r pipes (the %>% symbol) and html_element function:
# we can use css selectors:
print(tree %>% html_element(".products>a") %>% html_text())
# "[1] "\nCat Food\nDog Food\n""

# or XPath:
print(tree %>% html_element(xpath="//div[@class='products']/a") %>% html_text())
# "[1] "\nCat Food\nDog Food\n""

# Additionally rvest offers many quality of life functions:
# html_text2 - removes trailing and leading spaces and joins values
print(tree %>% html_element("div") %>% html_text2())
# "[1] "Cat Food Dog Food""

# html_attr - selects element's attribute:
print(tree %>% html_element("div") %>% html_attr('class'))
# "products"
const got = require('got');

// GET requests are default and can be made calling the module as is:
const response = await got('https://api.example.com');
console.log(response.body);

// POST requests can send 
const response = await got.post('https://api.example.com', {
    json: { name: 'John Doe' },
});
console.log(response.body);

// handling cookies
import {CookieJar} from 'tough-cookie';

const cookieJar = new CookieJar();

await cookieJar.setCookie('foo=bar', 'https://httpbin.org');
await got('https://httpbin.org/anything', {cookieJar});

// using proxy
import got from 'got';
import {HttpsProxyAgent} from 'hpagent';

await got('https://httpbin.org/ip', {
  agent: {
    https: new HttpsProxyAgent({
      keepAlive: true,
      keepAliveMsecs: 1000,
      maxSockets: 256,
      maxFreeSockets: 256,
      scheduling: 'lifo',
      proxy: 'https://localhost:8080'
    })
  }
});

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