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xpathvschompjs

MIT 13 2 646
58.1 thousand (month) Jun 08 2019 (a day ago)
175 1 4 MIT
1.2.3(2 months ago) Jul 30 2007 15.5 thousand (month)

xpath is a library for Go that allows you to use XPath expressions to select elements from an HTML document. It is built on top of the html package in the Go standard library, and provides a way to select elements from an HTML document using XPath expressions, which are more powerful and expressive than CSS selectors.

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


package main

import (
  "fmt"
  "github.com/antchfx/xpath"
  "golang.org/x/net/html"
  "strings"
)

func main() {
  // Create an HTML string
  html := `<html>
        <body>
          <div id="content">
            <p>Hello, World!</p>
            <a href="http://example.com">Example</a>
          </div>
        </body>
      </html>`

  // Parse the HTML string into a node tree
  doc, err := html.Parse(strings.NewReader(html))
  if err != nil {
    fmt.Println("Error:", err)
    return
  }

  // Compile the XPath expression
  expr, err := xpath.Compile("//p")
  if err != nil {
    fmt.Println("Error:", err)
    return
  }

  // Use the Evaluate method to select elements from the document
  nodes, err := expr.Evaluate(xpath.NodeNavigator(doc))
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  if nodes.MoveNext() {
    fmt.Println(nodes.Current().Value())
    // > Hello, World!
  }
}
# 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'])

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