WpkSnoop

A .NET tool that searches and extracts Webpack chunk loaders from .js files.

The extractor supports:

• Chunk loader that uses an object expression (e.g., {100: "chunk1", 101: "chunk2"}[e] + ".js")
• Chunk loader that uses if statements (e.g., if (100 === e) return "chunk.js")
• Chunk loader that uses ternary operator (?:) (e.g., 100 === e ? "chunk.js" : ...)
• Chunk loader that uses switch statement (e.g., switch (e) { case 100: return "chunk.js" })
• Chunk loader that uses array lookup (e.g., ["chunk1.js", "chunk2.js"][e])

For an overview of how this works read DOC.md.

Note: I don't intend to continue developing this tool any further, as there are better alternatives available, such as jxscout. This project began as a research experiment to explore chunk detection algorithms, and it's reached its conclusion.

Building

Build with .NET.

dotnet publish src/WpkSnoop.Cli/WpkSnoop.Cli.csproj -c Release -o .

You might receive some JINT warning when compiling as native AOT but the tool seems to work fine after some testing.

Usage

Description:
  Webpack Chunk Loader Extractor

Usage:
  wpksnoop <path> [options]

Arguments:
  <path>  Path to the JS file containing the chunk loader

Options:
  -d, --dir                Specifies that the path is a directory path
  -v, --verbose            Specifies verbose output
  -H, --header <header>    Specifies the HTTP headers for chunk file GET requests
  -D, --domain <domain>    Specifies the base URL for chunk file GET requests
  -x, --proxy <proxy>      Specifies the proxy URL for chunk file GET requests
  -k, --insecure           Specifies to not validate HTTPS certificates for chunk file GET requests
  -t, --threads <threads>  Specifies the number of threads to use [default: 2147483647]
  --version                Show version information
  -?, -h, --help           Show help and usage information

Examples

Sample JS files can be found under tests/WpkSnoop.Core.Test/Samples/. They are used to test different chunk loaders generated by Webpack.

Single .js File

wpksnoop tests/WpkSnoop.Core.Test/Samples/small.js

Directory With .js Files

wpksnoop -d tests/WpkSnoop.Core.Test/Samples/

Sending GET Requests

Used to send all the found chunk loader entries to a site.

wpksnoop tests/WpkSnoop.Core.Test/Samples/small.js -D 'https://example.com/chunks/'

The chunk loader entries can also go through a proxy, useful for using tools like burp.

wpksnoop tests/WpkSnoop.Core.Test/Samples/small.js -v -D 'https://example.com/chunks/' -x 'http://localhost:8080'

HTTP headers can be added by using -H.

wpksnoop tests/WpkSnoop.Core.Test/Samples/small.js -v -D 'https://example.com/chunks/' -H 'Cookie: 1' -H 'Cookie: 2'

Generate Webpack Files

Sample Webpack project used for testing can be found under webpack/. Generate Webpack files by:

cd webpack
npm install
npm run build

The generated Webpack files will be under webpack/dist/.

Limitations

See issues.