esbuild-plugin-kaitai

An esbuild plugin to compile Kaitai struct files.

Prerequisites

• esbuild >= 0.11.0
• nodejs >= 10.0.0
• The Kaitai Compiler >= 0.9

Installation

Install the plugin from your javascript package manager

# yarn
yarn add --dev esbuild-plugin-kaitai

# or npm
npm install --save-dev esbuild-plugin-kaitai

Usage

Typescript

Note: The Kaitai Compiler and Runtime do not directly support Typescript yet, but there's some workarounds you can use to get everything working nicely.

1. Replace the kaitai-struct runtime with @tschrock/kaitai-struct for typescript support

   $ npm install kaitai-struct@npm:@tschrock/kaitai-struct
   

2. Write a type shim for your .ksy file.

   I have written an experimental type generator for .ksy files. It's not perfect, and will probably break for complex schemas, but it will give you a good starting point.

   Installation

   $ npm i -g @tschrock/kaitai-dts

   Usage

   $ kaitai-dts my-data.ksy

   // my-data.ksy.d.ts
   declare module "my-data.ksy" {
       class MyData {
           version: string;
           recordType: MyData.ExampleEnum;
           recordData: UInt8Array;
           constructor(_io: any, _parent?: any, _root?: any);
           _read(): void;
       }
       namespace MyData {
           enum ExampleEnum {
               ITEM_1 = 1,
               ITEM_2 = 2,
               ITEM_3 = 3,
           }
       }
   }

3. Add the kaitai plugin to the list of plugins in your build script:

   // build.ts
   import esbuild from 'esbuild';
   import kaitaiLoader from 'esbuild-plugin-kaitai';
   
   esbuild.build({
       ...
       plugins: [
           kaitaiLoader({
               // Plugin config
           })
       ]
       ...
   });

4. You can now directly import .ksy files in your application, and esbuild will automatically compile them.

   // myapp.ts
   import { readFileSync } from 'fs';
   import KaitaiStream from 'kaitai-struct/KaitaiStream';
   import MyData from 'my-data.ksy';
   
   const myDataBin = readFileSync("./mydata.bin")
   const myData = new MyData(new KaitaiStream(myDataBin));
   console.log(myData);

Javascript (modules)

1. Add the kaitai plugin to the list of plugins in your build script:

   // build.js
   import esbuild from 'esbuild';
   import kaitaiLoader from 'esbuild-plugin-kaitai';
   
   esbuild.build({
       ...
       plugins: [
           kaitaiLoader({
               // Plugin config
           })
       ]
       ...
   });

2. You can now directly import .ksy files in your application, and esbuild will automatically compile them.

   // myapp.js
   import { readFileSync } from 'fs';
   import KaitaiStream from 'kaitai-struct/KaitaiStream';
   import MyData from 'my-data.ksy';
   
   const myDataBin = readFileSync("./mydata.bin")
   const myData = new MyData(new KaitaiStream(myDataBin));
   console.log(myData);

Javascript (commonjs)

1. Add the kaitai plugin to the list of plugins in your build script:

   // build.js
   const esbuild = require('esbuild');
   const kaitaiLoader = require('esbuild-plugin-kaitai');
   
   esbuild.build({
       ...
       plugins: [
           kaitaiLoader({
               // Plugin config
           })
       ]
       ...
   });

2. You can now directly require .ksy files in your application, and esbuild will automatically compile them.

   // myapp.js
   const { readFileSync } = require('fs');
   const KaitaiStream  = require('kaitai-struct/KaitaiStream');
   const MyData = require('my-data.ksy');
   
   const myDataBin = readFileSync("./mydata.bin")
   const myData = new MyData(new KaitaiStream(myDataBin));
   console.log(myData);

Configuration

Using the CLI Compiler

Option	Type	Description
compilerPath	string	Optional. The path to the kaitai compiler binary.
compilerFlags	string[]	Optional. Extra CLI flags to pass to the kaitai compiler.
compilerTimeout	number	Optional. A timeout for the compiler.

Using the Compiler API

Note: See licensing info below

Option	Type	Description
compiler	Compiler	Required. The kaitai compiler.
fileLoader	FileLoader	Optional. The file loader.
debug	boolean	Optional. Create a debug build.

For Example:

import esbuild from 'esbuild';
import kaitaiLoader from 'esbuild-plugin-kaitai';
import KaitaiStructCompiler from 'kaitai-struct-compiler';

esbuild.build({
    ...
    plugins: [
        kaitaiLoader({
            compiler: new KaitaiStructCompiler(),
            debug: true
        })
    ]
    ...
});

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

Extra Licensing Info

The reference Kaitai compiler, kaitai-struct-compiler, is licened under the GPL-3.0 license. In order to prevent license compatability issues, this project does not include or directly link to the kaitai compiler. As the user, you must provide the compiler program yourself. There are two ways you can do this:

CLI Compiler (default)

By default, this plugin will attempt to execute the Kaitai compiler program from the command line. Since the compiler runs as a separate program, this should avoid any licensing conflicts.

1. Download and Install the Kaitai Compiler from the Kaitai website.

2. Make sure the kaitai-struct-compiler program is in your PATH.

If the Kaitai compiler is not in your PATH, you can specify it's location using the compilerPath configuration option or KAITAI_PATH environment variable.

Compiler API

You can also provide your own compiler via the compiler configuration option. You can either provide the reference compiler (In which case your build scrips might be subject to the GPL - don't ask me, I'm not a lawyer), or you can provide an alternative, API-compatable compiler.