rvestvsnestful
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
Nestful is a Ruby library for making HTTP requests. It is designed to provide a simple, easy-to-use interface for making requests and handling responses. Nestful is often used for making requests to RESTful APIs.
One of the main features of Nestful is its ability to automatically parse JSON and XML responses and return them as Ruby objects. This allows developers to easily access the data returned by an API without having to manually parse the response.
Netful is aimed at interacting with rest APIs and provides a convenient interface (see example below)
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"
require 'nestful'
# GET request
response = Nestful.get('http://httpbin.org/get')
puts response.body
puts response.code
puts response.headers
# POST request
response = Nestful.post(
'http://httpbin.org/post',
:format => :json, :payload => { :title => 'foo', :body => 'bar', :userId => 1 }
)
puts response.body
# establish interface to a specific API
class Charge < Nestful::Resource
endpoint 'https://api.stripe.com/v1/charges'
options :auth_type => :bearer, :password => 'sk_bar'
def self.all
self.new(get)
end
def self.find(id)
self.new(get(id))
end
def refund
post(:refund)
end
end
Charge.all #=> []
Charge.find('ch_bar').amount