demystify-lite.py

"""Demystify-lite Pyscript front-end.

The form for Demystify is cleared and a user can then provide the
page with a File handle to a file-format analysis report on their own
file-system. The file is processed and the results returned to the page.
"""

import binascii
import json
import tempfile

from js import document, console, window, alert
from pyodide.ffi import create_proxy

from demystify.demystify import analysis_from_csv_lite
from demystify.libs.outputhandlers.htmloutputclass import FormatAnalysisHTMLOutput


from pyscript import when, display


def clear_data():
    """Clear the metadata fields associated with the file input and
    output.
    """
    document.getElementById("filename").innerHTML = ""
    document.getElementById("filesize").innerHTML = ""
    document.getElementById("filetype").innerHTML = ""
    document.getElementById("filedate").innerHTML = ""
    document.getElementById("results").innerHTML = ""


async def deny_list(event):
    """Handle file select and follow-on actions from HTML/Pyscript."""
    use_deny_list = document.getElementById("use_deny_list").checked
    if not use_deny_list:
        document.getElementById("denylistTextBox").style.display = "none"
        return

    document.getElementById("denylistTextBox").style.display = ""

    content = document.getElementById("denylist").value
    if content.strip() == "":
        with open("default_denylist.cfg", encoding="utf-8") as default_deny_list:
            content = default_deny_list.read()
            deny_list_json = json.dumps(json.loads(content), indent=2)
            document.getElementById("denylist").value = deny_list_json


@when("click", "#analysis_button")
async def click_handler(event):
    """
    Event handlers get an event object representing the activity that raised
    them.

    https://github.com/exponential-decay
    """
    await file_select()


async def report_select(event):
    """Run analysis from an existing report."""

    console.log("using existing report...")
    clear_data()
    event.stopPropagation()
    event.preventDefault()
    deny_list = "{}"
    use_deny_list = document.getElementById("use_deny_list").checked
    if use_deny_list:
        deny_list = document.getElementById("denylist").value
    try:
        deny_list = json.loads(deny_list)
    except json.decoder.JSONDecodeError as err:
        console.log(f"denylist error: {err}")
        document.getElementById("results").innerHTML = (
            "<br/>"
            "<h1>Processing Error</h1>"
            "deny list JSON is invalid, please check, e.g. via "
            "<a href='https://jsonlint.com/' target='_blank', rel='noopener'>JSONLint.com</a>"
            "<br/>"
        )
        return
    files = event.target.files
    for file in files:
        document.getElementById("filename").innerHTML = f"<b>File Name:</b> {file.name}"
        document.getElementById("filesize").innerHTML = f"<b>File Size:</b> {file.size}"
        if file.type:
            document.getElementById(
                "filetype"
            ).innerHTML = f"<b>File Type:</b> {file.type}"
        document.getElementById(
            "filedate"
        ).innerHTML = f"<b>File date:</b> {file.lastModified}"
        content = await file.text()
        with tempfile.NamedTemporaryFile("w", encoding="UTF8") as temp_file:
            temp_file.write(content)
            analysis = analysis_from_csv_lite(
                temp_file.name,
                label=file.name,
                denylist=deny_list,
            )
            out = ""
            try:
                out = FormatAnalysisHTMLOutput(
                    analysis.analysis_results
                ).printHTMLResults()
            except AttributeError:
                out = (
                    f"<b>{analysis}</b>"
                    "Error processing content. Press F12 on your keyboard to open"
                    "developer tools, then select the console tab to view"
                    "additional debug output."
                )
            document.getElementById("results").innerHTML = out


async def file_select():
    """Handle file select and follow-on actions from HTML/Pyscript."""

    console.log("using sf wasm...")
    clear_data()
    deny_list = "{}"
    use_deny_list = document.getElementById("use_deny_list").checked
    if use_deny_list:
        deny_list = document.getElementById("denylist").value
    try:
        deny_list = json.loads(deny_list)
    except json.decoder.JSONDecodeError as err:
        console.log(f"denylist error: {err}")
        document.getElementById("results").innerHTML = (
            "<br/>"
            "<h1>Processing Error</h1>"
            "deny list JSON is invalid, please check, e.g. via "
            "<a href='https://jsonlint.com/' target='_blank', rel='noopener'>JSONLint.com</a>"
            "<br/>"
        )
        return
    results = document.getElementById("sf-results")
    content = results.value
    content = content.strip()
    bytes = content[:25]
    bytes = binascii.hexlify(bytes.encode())
    expected_bytes = b"2d2d2d0a7369656766726965642020203a"
    console.log(f"{expected_bytes in bytes}")
    console.log(f"received {bytes}")
    console.log(f"expected {expected_bytes}")
    if not content:
        console.log("you need to select a file or directory for analysis...")
        return
    with tempfile.NamedTemporaryFile("w", encoding="UTF8", delete=False) as temp_file:
        temp_file.write(content)
    with open(temp_file.name, "r", encoding="utf8") as test:
        console.log(test.read())
    analysis = analysis_from_csv_lite(
        temp_file.name,
        label="Siegfried Browser-Based Analysis (WASM)",
        denylist=deny_list,
    )
    out = ""
    try:
        out = FormatAnalysisHTMLOutput(analysis.analysis_results).printHTMLResults()
    except AttributeError:
        out = (
            f"<b>{analysis}</b>"
            "Error processing content. Press F12 on your keyboard to open"
            "developer tools, then select the console tab to view"
            "additional debug output."
        )
    document.getElementById("results").innerHTML = out


def setup_button():
    """Create a Python proxy for the callback function."""
    file_select_proxy = create_proxy(report_select)
    document.querySelector("#report_select input[type='file']").addEventListener(
        "change",
        file_select_proxy,
        False,
    )
    deny_list_proxy = create_proxy(deny_list)
    document.querySelector("#deny_list input[type='checkbox']").addEventListener(
        "change",
        deny_list_proxy,
    )


if __name__ == "__main__":
    setup_button()