nested-decoder.kt

package burp;

import java.awt.Component
import java.util.*

class MessageEditorTab : IMessageEditorTab {
    var messageEditor = BurpExtender.cb.createMessageEditor(null, true)

    override fun getMessage(): ByteArray {
        return messageEditor.message
    }

    override fun isModified(): Boolean {
        return messageEditor.isMessageModified
    }

    override fun getTabCaption(): String {
        return "Base64"
    }

    override fun getSelectedData(): ByteArray? {
        return null
    }

    override fun getUiComponent(): Component {
        return messageEditor.component
    }

    override fun setMessage(content: ByteArray, isRequest: Boolean) {
        messageEditor.setMessage(decodeBody(content, isRequest), isRequest)
    }

    override fun isEnabled(content: ByteArray, isRequest: Boolean): Boolean {
        try {
            return decodeBody(content, isRequest).size > 0
        }
        catch(ex: IllegalArgumentException) {
            return false
        }
    }

    fun decodeBody(content: ByteArray, isRequest: Boolean): ByteArray {
        val helpers = BurpExtender.cb.helpers
        var body: ByteArray
        if(isRequest) {
            body = Arrays.copyOfRange(content, helpers.analyzeRequest(content).bodyOffset, content.size)
        }
        else {
            body = Arrays.copyOfRange(content, helpers.analyzeResponse(content).bodyOffset, content.size)
        }
        return Base64.getDecoder().decode(body)
    }

}


class MessageEditorTabFactory : IMessageEditorTabFactory {
    override fun createNewInstance(controller: IMessageEditorController?, editable: Boolean): IMessageEditorTab {
        return MessageEditorTab()
    }
}


class BurpExtender : IBurpExtender {

    companion object {
        lateinit var cb: IBurpExtenderCallbacks
    }

    override fun registerExtenderCallbacks(callbacks: IBurpExtenderCallbacks) {
        cb = callbacks
        cb.registerMessageEditorTabFactory(MessageEditorTabFactory())
    }
}