htmlparser2vschompjs
htmlparser2 is a Node.js library for parsing HTML and XML documents. It works by building a tree of elements, similar to the Document Object Model (DOM) in web browsers. This allows you to easily traverse and manipulate the structure of the document.
htmlparser2 is a low-level html tree parser but it can still be useful in web scraping as it's a powerful tool for HTML restructuring and serialization.
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.
Example Use
const htmlparser = require("htmlparser2");
const parser = new htmlparser.Parser({
onopentag: (name, attribs) => {
console.log(`Opening tag: ${name}`);
},
ontext: (text) => {
console.log(`Text: ${text}`);
},
onclosetag: (name) => {
console.log(`Closing tag: ${name}`);
}
}, {decodeEntities: true});
const html = "<p>Hello, <b>world</b>!</p>";
parser.write(html);
parser.end();
# 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'])