def api_submit():
    """
    Blocking POST handler for file submission.
    Runs snort on supplied file and returns results as json text.
    """
    data = request.files.file
    response.content_type = 'application/json'
    if not data or not hasattr(data, 'file'):
        return json.dumps({"status": "Failed", "stderr": "Missing form params"})
    return json.dumps(analyse_pcap(data.file, data.filename), default=jsondate, indent=4)