initial commit

.gitignore

@@ -0,0 +1,2 @@
+keys/*.pem
+__pycache__/

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Ian
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,97 @@
+# KGet Capture
+
+A Chrome (and other Chromium-browser) extension that sends downloads to
+[KGet](https://apps.kde.org/kget/), KDE's download manager, instead of (or in
+addition to) the browser's built-in downloader.
+
+- Right-click any link, image, video, or audio element and choose
+  **"Download with KGet"** to open KGet's "New Download" dialog, prefilled
+  with the URL — edit the filename or destination folder if you want, then
+  confirm to start the transfer.
+- A toolbar toggle enables **auto-capture**: while on, every download Chrome
+  starts is cancelled and redirected to the same KGet dialog automatically.
+  Defaults to ON.
+
+## Requirements
+
+- Linux with KGet installed (and running, or set to autostart)
+- One of: Google Chrome, Chromium, Brave, Vivaldi, Microsoft Edge
+- `python3` and `dbus-send` on `PATH` (standard on virtually all Linux/KDE
+  systems already)
+
+## Install
+
+```bash
+git clone <this-repo-url> kget-capture
+cd kget-capture
+./install.sh
+```
+
+`install.sh` registers a native messaging host for every supported browser it
+finds installed, then prints the extension's fixed ID and next steps:
+
+1. Open `chrome://extensions` (or your browser's equivalent).
+2. Enable **Developer mode** (top-right toggle).
+3. Click **Load unpacked** and select this repo's `extension/` directory.
+4. Confirm the loaded extension's ID matches the one `install.sh` printed.
+
+## Usage
+
+- **On-demand:** right-click a link/image/video/audio → "Download with KGet".
+- **Automatic:** click the toolbar icon and flip "Auto-capture all downloads"
+  on or off. The badge shows "ON" (green) or "OFF" (grey).
+
+## Uninstall
+
+```bash
+./uninstall.sh
+```
+
+This removes the native messaging host registrations and the installed host
+script. You'll still need to remove the unpacked extension yourself via
+`chrome://extensions` — that step can't be scripted.
+
+## Known limitations
+
+- **`blob:`/`data:` URLs can't be captured.** There's no real network URL to
+  hand to KGet, so these downloads proceed normally through Chrome (a console
+  warning is logged in the extension's service worker).
+- **Auto-capture has a brief head start.** Manifest V3 removed blocking
+  `webRequest`, so Chrome begins the download before the extension can cancel
+  it. A small/partial temp file may transiently appear before it's erased.
+- **A KGet dialog opens for every capture.** The extension uses KGet's
+  `showNewTransferDialog` D-Bus method, which opens the interactive "New
+  Download" dialog rather than starting the transfer immediately. This is
+  intentional — it lets you rename the file or change the destination folder
+  before it starts. If you'd rather it start immediately without a prompt,
+  see [Troubleshooting](#troubleshooting) for the alternate `addTransfer`
+  call — note that route only returns once the dialog is dismissed, so it's
+  not what the extension uses by default.
+- **KGet must already be running.** If it's not, captures fail silently from
+  the user's perspective — check the service worker console for the actual
+  error (see Troubleshooting).
+
+## Troubleshooting
+
+- **Check native host registration:** confirm
+  `~/.config/<browser>/NativeMessagingHosts/com.kget_capture.host.json` exists
+  and its `path` points at an executable file
+  (`~/.local/share/kget-capture/kget_capture_host.py`).
+- **Inspect the extension's logs:** on `chrome://extensions`, find "KGet
+  Capture", click "service worker" under "Inspect views" to open its console.
+- **Test D-Bus directly:**
+  ```bash
+  dbus-send --print-reply --dest=org.kde.kget /KGet \
+    org.kde.kget.main.showNewTransferDialog array:string:"https://example.com/file.zip"
+  ```
+  If this fails with `ServiceUnknown`, KGet isn't running. To skip the dialog
+  and start a transfer straight away instead, use `addTransfer` with a real
+  destination folder:
+  ```bash
+  dbus-send --print-reply --dest=org.kde.kget /KGet \
+    org.kde.kget.main.addTransfer string:"https://example.com/file.zip" string:"$HOME/Downloads" boolean:true
+  ```
+
+## License
+
+MIT — see [LICENSE](LICENSE).

extension/background.js

@@ -0,0 +1,79 @@
+const NATIVE_HOST = "com.kget_capture.host";
+const MENU_ID = "kget-capture-download";
+
+function updateBadge(enabled) {
+  chrome.action.setBadgeText({ text: enabled ? "ON" : "OFF" });
+  chrome.action.setBadgeBackgroundColor({ color: enabled ? "#2e7d32" : "#9e9e9e" });
+}
+
+async function refreshBadge() {
+  const { autoCaptureEnabled } = await chrome.storage.local.get({ autoCaptureEnabled: true });
+  updateBadge(autoCaptureEnabled);
+}
+
+function sendToKGet(url) {
+  chrome.runtime.sendNativeMessage(NATIVE_HOST, { action: "addTransfer", url }, (response) => {
+    if (chrome.runtime.lastError) {
+      console.error("[kget-capture] native host error:", chrome.runtime.lastError.message);
+      return;
+    }
+    if (!response || !response.ok) {
+      console.error("[kget-capture] KGet reported failure:", response && response.error);
+    }
+  });
+}
+
+chrome.runtime.onInstalled.addListener(async (details) => {
+  chrome.contextMenus.create({
+    id: MENU_ID,
+    title: "Download with KGet",
+    contexts: ["link", "image", "video", "audio"],
+  });
+
+  if (details.reason === "install") {
+    await chrome.storage.local.set({ autoCaptureEnabled: true });
+  }
+  refreshBadge();
+});
+
+chrome.contextMenus.onClicked.addListener((info) => {
+  if (info.menuItemId !== MENU_ID) return;
+  const url = info.linkUrl || info.srcUrl;
+  if (!url) return;
+  sendToKGet(url);
+});
+
+chrome.downloads.onCreated.addListener(async (item) => {
+  const { autoCaptureEnabled } = await chrome.storage.local.get({ autoCaptureEnabled: true });
+  if (!autoCaptureEnabled) return;
+
+  const url = item.finalUrl || item.url;
+  if (url.startsWith("blob:") || url.startsWith("data:")) {
+    console.warn("[kget-capture] cannot redirect blob:/data: URL, letting Chrome handle it:", url);
+    return;
+  }
+
+  try {
+    await chrome.downloads.cancel(item.id);
+    // erase() only clears the history entry -- it does NOT delete the
+    // partial file Chrome already wrote to disk. removeFile() does that.
+    await chrome.downloads.removeFile(item.id);
+  } catch (e) {
+    // Expected if Chrome finished the download before cancel() landed, or
+    // hadn't written any bytes yet -- not worth surfacing to the user.
+  }
+  try {
+    await chrome.downloads.erase({ id: item.id });
+  } catch (e) {
+    console.error("[kget-capture] failed to erase Chrome download entry:", e);
+  }
+  sendToKGet(url);
+});
+
+chrome.storage.onChanged.addListener((changes, area) => {
+  if (area === "local" && "autoCaptureEnabled" in changes) {
+    updateBadge(changes.autoCaptureEnabled.newValue);
+  }
+});
+
+refreshBadge();

extension/manifest.json

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+{
+  "manifest_version": 3,
+  "name": "KGet Capture",
+  "version": "1.0.0",
+  "description": "Send browser downloads to KGet (KDE Download Manager) on Linux.",
+  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtM1nFg5pPd3UBzynUJHj6aUy7bjudZaX9AQTWGMqAX3fXylw1lubSzP1/BaS9ivvgOJg/loyEgzEZlcNPzblFVlg8BqEJ3tntdk2OzYvUs0pUdcPzzyjso9TykCkUUTI7ev8JkreW/FYlinfvNwSYN4/c1s3h8/I6XHtxOdmO1G3bS98+BQaXPldbDmxoKwyWR8u1f8gTO2Mg3GY4BHau3RWf1kgtNzh20p9wE3sEFdWkFu7ArgRCIrWLh6m3O6lolnHQSCWPwtOTx893Qkp9Eu6FwUnoWc8rsYx8sqa0eNCTCS6Kjr1Iu3yEJ5y9390jUiDZTQ/c62ueCTQaYv2bwIDAQAB",
+  "permissions": ["downloads", "contextMenus", "storage", "nativeMessaging"],
+  "background": {
+    "service_worker": "background.js"
+  },
+  "action": {
+    "default_popup": "popup.html",
+    "default_icon": {
+      "16": "icons/icon16.png",
+      "32": "icons/icon32.png",
+      "48": "icons/icon48.png",
+      "128": "icons/icon128.png"
+    }
+  },
+  "icons": {
+    "16": "icons/icon16.png",
+    "48": "icons/icon48.png",
+    "128": "icons/icon128.png"
+  }
+}

extension/popup.css

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+body {
+  width: 240px;
+  padding: 12px;
+  font-family: system-ui, sans-serif;
+  font-size: 13px;
+}
+
+h1 {
+  font-size: 14px;
+  margin: 0 0 10px;
+}
+
+.toggle-row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  cursor: pointer;
+}
+
+.status {
+  margin: 8px 0 0;
+  color: #555;
+}
+
+.hint {
+  margin: 10px 0 0;
+  color: #777;
+  line-height: 1.4;
+}

extension/popup.html

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+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <link rel="stylesheet" href="popup.css">
+</head>
+<body>
+  <h1>KGet Capture</h1>
+  <label class="toggle-row">
+    <input type="checkbox" id="auto-capture-toggle">
+    <span>Auto-capture all downloads</span>
+  </label>
+  <p class="status" id="status-line"></p>
+  <p class="hint">Right-click any link, image, video, or audio and choose
+    "Download with KGet" to send it to KGet on demand.</p>
+  <script src="popup.js"></script>
+</body>
+</html>

extension/popup.js

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+const checkbox = document.getElementById("auto-capture-toggle");
+const statusLine = document.getElementById("status-line");
+
+function renderStatus(enabled) {
+  statusLine.textContent = `Auto-capture: ${enabled ? "ON" : "OFF"}`;
+}
+
+chrome.storage.local.get({ autoCaptureEnabled: true }).then(({ autoCaptureEnabled }) => {
+  checkbox.checked = autoCaptureEnabled;
+  renderStatus(autoCaptureEnabled);
+});
+
+checkbox.addEventListener("change", () => {
+  chrome.storage.local.set({ autoCaptureEnabled: checkbox.checked });
+  renderStatus(checkbox.checked);
+});

install.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+INSTALL_DIR="$HOME/.local/share/kget-capture"
+HOST_SCRIPT_SRC="$SCRIPT_DIR/native-host/kget_capture_host.py"
+HOST_SCRIPT_DEST="$INSTALL_DIR/kget_capture_host.py"
+MANIFEST_TEMPLATE="$SCRIPT_DIR/native-host/com.kget_capture.host.json"
+GENERATED_MANIFEST="$INSTALL_DIR/com.kget_capture.host.json"
+
+echo "Checking dependencies..."
+for dep in python3 dbus-send; do
+  if ! command -v "$dep" >/dev/null 2>&1; then
+    echo "ERROR: '$dep' is required but not found on PATH." >&2
+    exit 1
+  fi
+done
+
+echo "Installing native host script to $HOST_SCRIPT_DEST"
+mkdir -p "$INSTALL_DIR"
+cp "$HOST_SCRIPT_SRC" "$HOST_SCRIPT_DEST"
+chmod +x "$HOST_SCRIPT_DEST"
+
+echo "Generating native messaging host manifest..."
+sed "s|__HOST_SCRIPT_PATH__|$HOST_SCRIPT_DEST|" "$MANIFEST_TEMPLATE" > "$GENERATED_MANIFEST"
+
+declare -A BROWSER_DIRS=(
+  ["Google Chrome"]="$HOME/.config/google-chrome"
+  ["Chromium"]="$HOME/.config/chromium"
+  ["Brave"]="$HOME/.config/BraveSoftware/Brave-Browser"
+  ["Vivaldi"]="$HOME/.config/vivaldi"
+  ["Microsoft Edge"]="$HOME/.config/microsoft-edge"
+)
+
+registered_any=false
+for browser in "${!BROWSER_DIRS[@]}"; do
+  config_dir="${BROWSER_DIRS[$browser]}"
+  if [ -d "$config_dir" ]; then
+    target_dir="$config_dir/NativeMessagingHosts"
+    mkdir -p "$target_dir"
+    cp "$GENERATED_MANIFEST" "$target_dir/com.kget_capture.host.json"
+    echo "Registered native host for $browser"
+    registered_any=true
+  fi
+done
+
+if [ "$registered_any" = false ]; then
+  echo "WARNING: no supported browser config directories were found. Checked:"
+  for browser in "${!BROWSER_DIRS[@]}"; do
+    echo "  - ${BROWSER_DIRS[$browser]}"
+  done
+fi
+
+EXT_ID=$(cat "$SCRIPT_DIR/keys/extension-id.txt")
+
+cat <<EOF
+
+Install complete.
+
+Extension ID: $EXT_ID
+
+Next steps:
+  1. Open chrome://extensions (or the equivalent for your browser)
+  2. Enable "Developer mode" (top-right toggle)
+  3. Click "Load unpacked" and select: $SCRIPT_DIR/extension
+  4. Confirm the loaded extension's ID matches: $EXT_ID
+
+Make sure KGet is running (or set to autostart) for captures to work.
+EOF

keys/README.md

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+# Extension signing key
+
+This directory holds the RSA key pair used to pin the extension's Chrome ID so
+it's identical across every install (needed so the native messaging host's
+`allowed_origins` can be hardcoded instead of asking each user to paste their
+extension ID).
+
+- `kget-capture-private.pem` — **not committed** (see `.gitignore`). Keep it
+  somewhere safe if you want to be able to reproduce the same key deterministically
+  later; losing it just means a future re-key would get a new extension ID, it's
+  not a security incident.
+- `kget-capture-public.der` / `kget-capture-public.b64` — derived from the
+  private key. The base64 contents of `kget-capture-public.b64` is pasted
+  verbatim into `extension/manifest.json`'s `"key"` field. These are already
+  effectively public once checked into `manifest.json`, so committing them is
+  fine (and `extension-id.txt` too).
+- `extension-id.txt` — the 32-character Chrome extension ID derived from the
+  public key (also hardcoded into `native-host/com.kget_capture.host.json`).
+
+## Regenerating (only if rotating the key)
+
+```bash
+openssl genrsa -out keys/kget-capture-private.pem 2048
+openssl rsa -in keys/kget-capture-private.pem -pubout -outform DER -out keys/kget-capture-public.der
+openssl base64 -A -in keys/kget-capture-public.der -out keys/kget-capture-public.b64
+openssl dgst -sha256 -binary keys/kget-capture-public.der | head -c 16 | od -An -tx1 \
+  | tr -d ' \n' | tr '0123456789abcdef' 'abcdefghijklmnop' > keys/extension-id.txt
+```
+
+Rotating the key changes the extension ID, which means `extension/manifest.json`'s
+`"key"` and `native-host/com.kget_capture.host.json`'s `allowed_origins` both
+need updating to match.

keys/extension-id.txt

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+lgkhlfhejbffjnpcdlpjclicihnbjijp

keys/kget-capture-public.b64

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+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtM1nFg5pPd3UBzynUJHj6aUy7bjudZaX9AQTWGMqAX3fXylw1lubSzP1/BaS9ivvgOJg/loyEgzEZlcNPzblFVlg8BqEJ3tntdk2OzYvUs0pUdcPzzyjso9TykCkUUTI7ev8JkreW/FYlinfvNwSYN4/c1s3h8/I6XHtxOdmO1G3bS98+BQaXPldbDmxoKwyWR8u1f8gTO2Mg3GY4BHau3RWf1kgtNzh20p9wE3sEFdWkFu7ArgRCIrWLh6m3O6lolnHQSCWPwtOTx893Qkp9Eu6FwUnoWc8rsYx8sqa0eNCTCS6Kjr1Iu3yEJ5y9390jUiDZTQ/c62ueCTQaYv2bwIDAQAB

native-host/com.kget_capture.host.json

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+{
+  "name": "com.kget_capture.host",
+  "description": "Native messaging host that hands off download URLs to KGet via D-Bus",
+  "path": "__HOST_SCRIPT_PATH__",
+  "type": "stdio",
+  "allowed_origins": ["chrome-extension://lgkhlfhejbffjnpcdlpjclicihnbjijp/"]
+}

native-host/kget_capture_host.py

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+#!/usr/bin/env python3
+"""Native messaging host bridging Chrome to KGet's D-Bus service."""
+
+import json
+import struct
+import subprocess
+import sys
+
+
+def read_message():
+    raw_length = sys.stdin.buffer.read(4)
+    if len(raw_length) < 4:
+        return None
+    (length,) = struct.unpack("<I", raw_length)
+    data = sys.stdin.buffer.read(length)
+    return json.loads(data)
+
+
+def write_message(message):
+    data = json.dumps(message).encode("utf-8")
+    sys.stdout.buffer.write(struct.pack("<I", len(data)))
+    sys.stdout.buffer.write(data)
+    sys.stdout.buffer.flush()
+
+
+def add_transfer(url):
+    # showNewTransferDialog opens KGet's "New Download" dialog (editable name
+    # and destination) and returns immediately without waiting for the user
+    # to interact with it. addTransfer, by contrast, only returns once the
+    # dialog is dismissed when destDir is empty -- it blocks the D-Bus call
+    # on human input, which is why we don't use it here.
+    cmd = [
+        "dbus-send",
+        "--print-reply",
+        "--reply-timeout=10000",
+        "--dest=org.kde.kget",
+        "/KGet",
+        "org.kde.kget.main.showNewTransferDialog",
+        f"array:string:{url}",
+    ]
+    try:
+        result = subprocess.run(cmd, capture_output=True, text=True, timeout=15)
+    except FileNotFoundError:
+        return False, "dbus-send not found on this system"
+    except subprocess.TimeoutExpired:
+        return False, "dbus-send call timed out (is KGet running?)"
+
+    if result.returncode != 0:
+        stderr = result.stderr.strip()
+        return False, f"dbus-send failed: {stderr or 'unknown error'}"
+    return True, None
+
+
+def main():
+    message = read_message()
+    if not message or message.get("action") != "addTransfer" or "url" not in message:
+        write_message({"ok": False, "error": "invalid request"})
+        return
+
+    ok, error = add_transfer(message["url"])
+    write_message({"ok": True} if ok else {"ok": False, "error": error})
+
+
+if __name__ == "__main__":
+    main()

uninstall.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+INSTALL_DIR="$HOME/.local/share/kget-capture"
+
+BROWSER_DIRS=(
+  "$HOME/.config/google-chrome"
+  "$HOME/.config/chromium"
+  "$HOME/.config/BraveSoftware/Brave-Browser"
+  "$HOME/.config/vivaldi"
+  "$HOME/.config/microsoft-edge"
+)
+
+for config_dir in "${BROWSER_DIRS[@]}"; do
+  manifest="$config_dir/NativeMessagingHosts/com.kget_capture.host.json"
+  if [ -f "$manifest" ]; then
+    rm -f "$manifest"
+    echo "Removed $manifest"
+  fi
+done
+
+if [ -d "$INSTALL_DIR" ]; then
+  rm -rf "$INSTALL_DIR"
+  echo "Removed $INSTALL_DIR"
+fi
+
+cat <<EOF
+
+Uninstall complete.
+
+Note: this does not remove the unpacked extension itself. Remove it manually
+via chrome://extensions (or the equivalent for your browser).
+EOF