Added check_link feature.

- check_link feature ensures that the video is in a YouTube domain.

DownYouNow.ipynb

@@ -27,8 +27,7 @@
       "cell_type": "code",
       "execution_count": null,
       "metadata": {
-        "id": "tgACi8lLVS6Y",
-        "cellView": "form"
+        "id": "tgACi8lLVS6Y"
       },
       "outputs": [],
       "source": [
@@ -131,8 +130,15 @@
         "        \n",
         "        check_installDone('write')\n",
         "\n",
-        "def save_video(): \n",
+        "def check_link(): \n",
+        "    # Check the link if it is in YouTube. \n",
+        "    if ('.youtube.co' in user.video_link) or ('youtu.be' in user.video_link): \n",
+        "        return True\n",
+        "    else: \n",
+        "        fail(formatting.font.bold + 'The link is not YouTube. ' + formatting.clear)\n",
+        "        return False\n",
         "\n",
+        "def save_video(): \n",
         "    import google;\n",
         "\n",
         "    try:\n",
@@ -171,8 +177,10 @@
         "        start_download((video.video_title + '.' + user.audio_format))\n",
         "\n",
         "# Main. \n",
+        "try: \n",
         "    check_compatibility()\n",
         "    cleanup()\n",
+        "    check_link()\n",
         "\n",
         "    class user: \n",
         "        video_link = \"\" #@param {type:\"string\"}\n",
@@ -211,7 +219,9 @@
         "                output_format = '';\n",
         "\n",
         "    save_video()\n",
-        "download_video()"
+        "    download_video()\n",
+        "except: \n",
+        "    info.fail(formatting.font.bold + 'An error has ocurred, ' formatting.clear + 'we apologize for the inconvenience. Please check the log for full details. ')"
       ]
     }
   ],