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chompjsvsselectolax

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chompjs can be used in web scrapping for turning JavaScript objects embedded in pages into valid Python dictionaries.

In web scraping this is particularly useful for parsing Javascript variables like:

import chompjs
js = """
  var myObj = {
    myMethod: function(params) {
    // ...
    },
    myValue: 100
  }
"""
chompjs.parse_js_object(js, json_params={'strict': False})
{'myMethod': 'function(params) {\n        // ...\n    }', 'myValue': 100}

In practice this can be used to extract hidden JSON data like data from <script id=__NEXT_DATA__> elements from nextjs (and similar) websites. Unlike json.loads command chompjs can ingest json documents that contain javascript natives like functions making it a super easy way to scrape hidden web data objects.

selectolax is a fast and lightweight library for parsing HTML and XML documents in Python. It is designed to be a drop-in replacement for the popular BeautifulSoup library, with significantly faster performance.

selectolax uses a Cython-based parser to quickly parse and navigate through HTML and XML documents. It provides a simple and intuitive API for working with the document's structure, similar to BeautifulSoup.

To use selectolax, you first need to install it via pip by running pip install selectolax``. Once it is installed, you can use theselectolax.html.fromstring()function to parse an HTML document and create a selectolax object. For example:

from selectolax.parser import HTMLParser

html_string = "<html><body>Hello, World!</body></html>"
root = HTMLParser(html_string).root
print(root.tag) # html
You can also useselectolax.html.fromstring()with file-like objects, bytes or file paths, as well asselectolax.xml.fromstring()`` for parsing XML documents.

Once you have a selectolax object, you can use the select() method to search for elements in the document using CSS selectors, similar to BeautifulSoup. For example:

body = root.select("body")[0]
print(body.text()) # "Hello, World!"

Like BeautifulSoups find and find_all methods selectolax also supports searching using the search()`` method, which returns the first matching element, and thesearch_all()`` method, which returns all matching elements.

Example Use


# basic use
import chompjs
js = """
  var myObj = {
    myMethod: function(params) {
    // ...
    },
    myValue: 100
  }
"""
chompjs.parse_js_object(js, json_params={'strict': False})
{'myMethod': 'function(params) {\n        // ...\n    }', 'myValue': 100}

# example how to use with hidden data parsing:
import httpx
import chompjs
from parsel import Selector

response = httpx.get("http://example.com")
hidden_script = Selector(response.text).css("script#__NEXT_DATA__::text").get()
data = chompjs.parse_js_object(hidden_script)
print(data['props'])
from selectolax.parser import HTMLParser

html_string = "<html><body>Hello, World!</body></html>"
root = HTMLParser(html_string).root
print(root.tag) # html

# use css selectors:
body = root.select("body")[0]
print(body.text()) # "Hello, World!"

# find first matching element:
body = root.search("body")
print(body.text()) # "Hello, World!"

# or all matching elements:
html_string = "<html><body><p>paragraph1</p><p>paragraph2</p></body></html>"
root = HTMLParser(html_string).root
for el in root.search_all("p"):
  print(el.text()) 
# will print:
# paragraph 1
# paragraph 2

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