panthervsrvest
Panther is a convenient standalone library to scrape websites and to run end-to-end tests using real browsers.
Panther is super powerful. It leverages the W3C's WebDriver protocol to drive native web browsers such as Google Chrome and Firefox.
Panther is very easy to use, because it implements Symfony's popular BrowserKit and DomCrawler APIs, and contains all the features you need to test your apps. It will sound familiar if you have ever created a functional test for a Symfony app: as the API is exactly the same! Keep in mind that Panther can be used in every PHP project, as it is a standalone library.
Panther automatically finds your local installation of Chrome or Firefox and launches them, so you don't need to install anything else on your computer, a Selenium server is not needed!
In test mode, Panther automatically starts your application using the PHP built-in web-server. You can focus on writing your tests or web-scraping scenario and Panther will take care of everything else.
Features:
- executes the JavaScript code contained in webpages
- supports everything that Chrome (or Firefox) implements
- allows taking screenshots
- can wait for asynchronously loaded elements to show up
- lets you run your own JS code or XPath queries in the context of the loaded page
- supports custom Selenium server installations
- supports remote browser testing services including SauceLabs and BrowserStack
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
Example Use
<?php
use Symfony\Component\Panther\Client;
require __DIR__.'/vendor/autoload.php'; // Composer's autoloader
$client = Client::createChromeClient();
// Or, if you care about the open web and prefer to use Firefox
$client = Client::createFirefoxClient();
$client->request('GET', 'https://api-platform.com'); // Yes, this website is 100% written in JavaScript
$client->clickLink('Get started');
// Wait for an element to be present in the DOM (even if hidden)
$crawler = $client->waitFor('#installing-the-framework');
// Alternatively, wait for an element to be visible
$crawler = $client->waitForVisibility('#installing-the-framework');
echo $crawler->filter('#installing-the-framework')->text();
$client->takeScreenshot('screen.png'); // Yeah, screenshot!
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"