Master jsrpc: From Browser Hook to Automated Data Extraction

Overview

This article provides a practical tutorial on using jsrpc for web‑scraping, covering browser hooking, function extraction, local service setup, action registration, and automated data fetching with Python.

1. Hook the Cookie

In the browser console execute:

Object.defineProperty(document, "cookie", {set:function(a){debugger}})

2. Open Debug Mode

Navigate to the next page and enable the debugger.

3. Locate the Encryption Function

In the Call Stack panel, expand entries until you find the encrypted function; its values correspond to the request parameters.

4. Export the Function

Run the following in the console (note the omission of parentheses): window.dcpeng = ct.update Note: Using ct.update() would assign the result instead of the function.

5. Close Debug Mode

Close the debugger to allow WebSocket injection.

6. Start the Local Service

Double‑click the compiled binary: win64-localhost.exe This launches the jsrpc server.

7. Inject jsrpc Client Code

Copy the entire content of JsEnv.js and paste it into the browser console (breakpoints may need to be disabled).

8. Connect to the Service

var demo = new Hlclient("ws://127.0.0.1:12080/ws?group=v&name=test");

9. Register an Action

// Register a method named "get_v"
// The second argument is a function; resolve receives the value to send to the server.
// The third argument (param) is optional.
demo.regAction("get_v", function(resolve, param) {
    // var c = "好困啊" + param;
    var c = dcpeng();
    resolve(c);
});

10. Retrieve Data via HTTP

Open the following URL in a browser (replace group and name with the values used during injection):

http://127.0.0.1:12080/go?group=v&name=test&action=get_v

11. Automate Requests with Python

Use the requests library to fetch the value of get_v and then send further requests.

import requests

v_url = "http://127.0.0.1:12080/go?group=v&name=test&action=get_v"
v_res = requests.get(url=v_url).json()["get_v"]

cookies = {
    'session': '6c78df1c-37aa-4574-bb50-99784ffb3697.Qcl0XN6livMeZ-7tbiNe-Ogn8L4',
    'v': v_res,
}

headers = {
    'Connection': 'keep-alive',
    'Accept': 'application/json, text/javascript, */*; q=0.01',
    'X-Requested-With': 'XMLHttpRequest',
    'hexin-v': 'A3_4zkkuI7xygCZatjHGiHM8DlgKZNPp7bnX-hFMGsZ175EOGTRjVv2IZ04i',
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36 Edg/97.0.1072.69',
    'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
    'Origin': 'http://spider.wangluozhe.com',
    'Referer': 'http://spider.wangluozhe.com/challenge/6',
    'Accept-Language': 'zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6',
}

data = {
    'page': '3',
    'count': '10',
}

response = requests.post('http://spider.wangluozhe.com/challenge/api/6', headers=headers, cookies=cookies, data=data, verify=False).json()
print(response)

The printed result matches the data shown on the web page.

12. Scale to Full Site

Wrap the request in a loop over page ranges to crawl the entire site.

Conclusion

The jsrpc tool enables rapid, black‑box data extraction without manual environment setup, making web‑scraping more efficient.