chompjsvsxmltodict
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.
xmltodict is a Python library that allows you to work with XML data as if it were JSON. It allows you to parse XML documents and convert them to dictionaries, which can then be easily manipulated using standard dictionary operations.
You can also use the library to convert a dictionary back into an XML document. xmltodict is built on top of the popular lxml library and provides a simple, intuitive API for working with XML data.
Note that despite using lxml conversion speeds can be quite slow for large XML documents and in web scraping this should be used to parse specific snippets instead of whole HTML documents.
xmltodict pairs well with JSON parsing tools like jmespath or jsonpath. Alternatively, it can be used in reverse mode to parse JSON documents using HTML parsing tools like CSS selectors and XPath.
It can be installed via pip by running pip install xmltodict command.
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'])
import xmltodict
xml_string = """
<book>
<title>The Great Gatsby</title>
<author>F. Scott Fitzgerald</author>
<publisher>Charles Scribner's Sons</publisher>
<publication_date>1925</publication_date>
</book>
"""
book_dict = xmltodict.parse(xml_string)
print(book_dict)
{'book': {'title': 'The Great Gatsby',
'author': 'F. Scott Fitzgerald',
'publisher': "Charles Scribner's Sons",
'publication_date': '1925'}}
# and to reverse:
book_xml = xmltodict.unparse(book_dict)
print(book_xml)
# the xml can be loaded and parsed using parsel or beautifulsoup:
from parsel import Selector
sel = Selector(book_xml)
print(sel.css('publication_date::text').get())
'1925'