{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "cce66876",
   "metadata": {},
   "source": [
    "# Interface Presseportal"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f12d7022",
   "metadata": {},
   "source": [
    "Das Presseportal bietet eine Platform, bei der mittels GET-requests die Pressemitteilungen verschiedener Institutionen (Polizei, Feuerwehr, ...), in bestimmten Zeiträumen in gegebenen Gebieten extrahiert werden können. Dafür gibt es auch eine API."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b07aef9f",
   "metadata": {},
   "source": [
    "Beispiel URL: `https://www.presseportal.de/blaulicht/d/polizei/l/hessen/30?startDate=2021-05-04&endDate=2021-05-04`"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "258338d0",
   "metadata": {},
   "source": [
    "Da eine große Menge an Tweets angefragt werden und Requests ziemlich lange benötigen, muss die Anfrage optimiert werden:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "b07fac3c",
   "metadata": {},
   "outputs": [],
   "source": [
    "import requests\n",
    "import calendar\n",
    "import time\n",
    "import os\n",
    "import csv\n",
    "\n",
    "from tqdm.notebook import tqdm\n",
    "from datetime import datetime\n",
    "from bs4 import BeautifulSoup"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0dfce15a",
   "metadata": {},
   "source": [
    "Um Pressemitteilungen sinnvoll zu speichern, werden sie als Klasse dargestellt:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "6c0b30a8",
   "metadata": {},
   "outputs": [],
   "source": [
    "class Pressemitteilung:\n",
    "    def __init__(self, article_id, timestamp, location, text, bundesland):\n",
    "        self.article_id = article_id\n",
    "        self.timestamp = timestamp\n",
    "        self.location = location\n",
    "        self.text = text\n",
    "        self.bundesland=bundesland\n",
    "    \n",
    "    def __str__(self):\n",
    "        return f\"[{self.article_id}] {self.timestamp} {self.location} | {' '.join(self.text.split()[:6])}\"\n",
    "    \n",
    "    def to_row(self):\n",
    "        return [self.article_id, self.timestamp, self.location, self.bundesland, self.text]"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "63cceebe",
   "metadata": {},
   "source": [
    "**Konstanten und Pfade**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "8bcc877f",
   "metadata": {},
   "outputs": [],
   "source": [
    "REQUEST_HEADERS = {\n",
    "    \"User-Agent\": (\n",
    "        \"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_5) AppleWebKit/537.36 \"\n",
    "        \"(KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36\"\n",
    "    )\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "c637ac38",
   "metadata": {},
   "outputs": [],
   "source": [
    "DATA_FOLDER = os.path.join(\"..\", \"data\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "f094dee0",
   "metadata": {},
   "outputs": [],
   "source": [
    "BUNDESLAENDER = [\n",
    "    \"baden-wuerttemberg\",\n",
    "    \"bayern\",\n",
    "    \"berlin-brandenburg\",\n",
    "    \"bremen\",\n",
    "    \"hamburg\",\n",
    "    \"hessen\",\n",
    "    \"mecklenburg-vorpommern\",\n",
    "    \"niedersachsen\",\n",
    "    \"nordrhein-westfalen\",\n",
    "    \"rheinland-pfalz\",\n",
    "    \"saarland\",\n",
    "    \"sachsen\",\n",
    "    \"sachsen-anhalt\",\n",
    "    \"schleswig-holstein\",\n",
    "    \"thueringen\",\n",
    "]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "84632391",
   "metadata": {},
   "outputs": [],
   "source": [
    "def requests_get(request):\n",
    "    return requests.get(request, headers=REQUEST_HEADERS)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "1af0bdbd",
   "metadata": {},
   "outputs": [],
   "source": [
    "def extract_response(response, bundesland=None):\n",
    "    \"\"\"Extrahiere aus der Response einer Request alle Pressemitteilungen\n",
    "    \n",
    "    Args:\n",
    "        response (:obj:`Response`)\n",
    "        bundesland (:obj:`str`): Kann mit angegeben, falls es in der Suche relevant war. Default = None\n",
    "    \n",
    "    Returns:\n",
    "        list of :obj:`Pressemitteilung`\n",
    "    \"\"\"\n",
    "    \n",
    "    mitteilungen = []\n",
    "    \n",
    "    soup = BeautifulSoup(response.content, 'html.parser')\n",
    "    for article in soup.find_all('article'):\n",
    "        data_url = article['data-url']\n",
    "        article_id = '-'.join(article['data-url'].split('/')[-2:])\n",
    "        meta = article.find('div')\n",
    "        \n",
    "        timestamp_str = meta.find(class_=\"date\")\n",
    "        \n",
    "        if timestamp_str is not None:\n",
    "            timestamp_str = timestamp_str.text\n",
    "            timestamp = datetime.strptime(timestamp_str, '%d.%m.%Y – %H:%M')\n",
    "        else:\n",
    "            timestamp = None\n",
    "        \n",
    "        location_str = meta.find(class_=\"news-topic\")\n",
    "        location_str = location_str.text if location_str is not None else None\n",
    "        \n",
    "        p_texts = article.findAll('p')\n",
    "        if len(p_texts) > 1:\n",
    "            text = p_texts[1].text\n",
    "        else:\n",
    "            text = ''\n",
    "        \n",
    "        mitteilungen.append(Pressemitteilung(article_id, timestamp, location_str, text, bundesland))\n",
    "    \n",
    "    return mitteilungen"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "c62c06c9",
   "metadata": {},
   "outputs": [],
   "source": [
    "def create_get_request(*, site=1, location=None, start_date=None, end_date=None):\n",
    "    \"\"\"Simulation einer API: Erzeuge aus Parametern eine URL\n",
    "    \n",
    "    Args:\n",
    "        site (int, default=1): Aktuelle Seite, auf der man sich befinden soll. Ist in der URL in 30er Schritten angegeben\n",
    "        location (:obj:`str`, default=None): Bundesland bzw. Stadt\n",
    "        start_date (:obj:`str`, default=None)\n",
    "        end_date (:obj:`str`, default=None)\n",
    "    Returns:\n",
    "        str: URL\n",
    "    \"\"\"\n",
    "    url = f\"https://www.presseportal.de/blaulicht/d/polizei\"\n",
    "    \n",
    "    if location is not None:\n",
    "        url += f\"/l/{location}\"\n",
    "    \n",
    "    if site > 1:\n",
    "        url += f\"/{site*30}\"\n",
    "    \n",
    "    if start_date is not None or end_date is not None:\n",
    "        url += \"?\"\n",
    "    \n",
    "        if start_date is not None:\n",
    "            url += f\"startDate={start_date}\"\n",
    "        \n",
    "            if end_date is not None:\n",
    "                url += \"&\"\n",
    "        \n",
    "        if end_date is not None:\n",
    "            url += f\"endDate={end_date}\"\n",
    "    \n",
    "    return url"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "1c67c9bc",
   "metadata": {},
   "source": [
    "## Beispiel: Hamburg "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "aff924d6",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'https://www.presseportal.de/blaulicht/d/polizei/l/hamburg/90?startDate=2021-01-13&endDate=2021-03-20'"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "url = create_get_request(location=\"hamburg\", site=3, start_date=\"2021-01-13\", end_date=\"2021-03-20\")\n",
    "url"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "id": "6e2b9091",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[6337-4840243] 2021-02-16 17:41:00 Hamburg | Hamburg (ots) - Tatzeit: 15.02.2021, 08:15\n",
      "[6337-4839937] 2021-02-16 13:14:00 Hamburg | Hamburg (ots) - Tatzeiten: a. 15.02.2021,\n",
      "[6337-4839709] 2021-02-16 11:33:00 Hamburg | Hamburg (ots) - Tatzeit: 15.02.2021, 18:25\n",
      "[6337-4839544] 2021-02-16 10:31:00 Hamburg | Hamburg (ots) - Zeit: 15.02.2021, 01:34\n",
      "[6337-4838489] 2021-02-15 11:48:00 Hamburg | Hamburg (ots) - Tatzeit: 14.02.2021; 19:17\n"
     ]
    }
   ],
   "source": [
    "for mitteilung in extract_response(requests_get(url))[:5]:\n",
    "    print(mitteilung)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e50af557",
   "metadata": {},
   "source": [
    "## Effizientes Einlesen"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b4a9580a",
   "metadata": {},
   "source": [
    "Um die Dateien sinnhaft zu extrahieren, ohne auf einen Schlag zu viele Anfragen zu tätigen, läuft das Programm synchron mit Pausen (1Sek / Anfrage). Die Hauptfunktion sucht für einen gegebenen Tag alle Pressemeldungen der Polizei und sortiert diese nach Bundesland bzw. Stadt."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "da927e30",
   "metadata": {},
   "outputs": [],
   "source": [
    "def _get_meldungen_for_date_and_bundesland(year, month, day, bundesland):\n",
    "    \"\"\"Suche alle Meldungen für ein Bundesland zu einem konkreten Tag\"\"\"\n",
    "\n",
    "    meldungen = []\n",
    "    site = 1\n",
    "    \n",
    "    start_date = datetime(year, month, day).strftime(\"%Y-%m-%d\")\n",
    "    end_date = datetime(year, month, day).strftime(\"%Y-%m-%d\")\n",
    "    request = create_get_request(site=site, location=bundesland, start_date=start_date, end_date=end_date)\n",
    "    \n",
    "    new_meldungen = extract_response(requests_get(request), bundesland=bundesland)\n",
    "    meldungen.extend(new_meldungen)\n",
    "    \n",
    "    pbar = tqdm(desc=bundesland)\n",
    "    while len(new_meldungen) != 0:\n",
    "        time.sleep(1)\n",
    "        site += 1\n",
    "        \n",
    "        request = create_get_request(\n",
    "            site=site, location=bundesland, start_date=start_date, end_date=end_date,\n",
    "        )\n",
    "        \n",
    "        new_meldungen = extract_response(requests_get(request), bundesland=bundesland)\n",
    "        meldungen.extend(new_meldungen)\n",
    "        pbar.update(1)\n",
    "    pbar.close()\n",
    "        \n",
    "    return meldungen"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "85508758",
   "metadata": {},
   "outputs": [],
   "source": [
    "def get_meldungen_for_date(year, month, day):\n",
    "    \"\"\"Extrahiere alle Meldungen für einen Tag\n",
    "    \n",
    "    Args:\n",
    "        year (int): Jahr\n",
    "        month (int): Monat\n",
    "        day (int): Tag\n",
    "    \"\"\"\n",
    "\n",
    "    meldungen_dict = {}\n",
    "    \n",
    "    for bundesland in BUNDESLAENDER:\n",
    "        meldungen = _get_meldungen_for_date_and_bundesland(year, month, day, bundesland)\n",
    "        meldungen_dict[bundesland] = meldungen\n",
    "    \n",
    "    return meldungen_dict"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f938d8a9",
   "metadata": {},
   "source": [
    "## Speichern der Daten in CSV-Dateien"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "67374d3b",
   "metadata": {},
   "source": [
    "Zur sinnvollen Speicherung werden alle Daten eines Tages in genau einer CSV-Datei gespeichert. Diese können danach (manuell) als ZIP des Monats zusammengefasst werden. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "276e700d",
   "metadata": {},
   "outputs": [],
   "source": [
    "def store_meldungen_in_csv(year, month, day):\n",
    "    \"\"\"Speichere alle Meldungen für ein Datum in einer CSV. Im Namen der CSV steht das Datum.\"\"\"\n",
    "\n",
    "    filename = f\"{year}-{month}-{day}_presseportal.csv\"\n",
    "    path = os.path.join(DATA_FOLDER, filename)\n",
    "    meldungen_per_bundesland = get_meldungen_for_date(year, month, day)\n",
    "    \n",
    "    with open(path, 'w', newline='', encoding='UTF8') as f:\n",
    "        writer = csv.writer(f)\n",
    "        writer.writerow(['article_id', 'timestamp', 'location', 'bundesland', 'content'])\n",
    "        \n",
    "        for bundesland, meldungen in meldungen_per_bundesland.items():\n",
    "            for meldung in meldungen:\n",
    "                writer.writerow(meldung.to_row())\n",
    "    \n",
    "    print(f\"File '{filename}' created\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "c5d0bdbd",
   "metadata": {},
   "outputs": [],
   "source": [
    "def store_month(year, month):\n",
    "    month_end_day = calendar.monthrange(year, month)[1]\n",
    "    \n",
    "    for i in range(0, month_end_day):\n",
    "        store_meldungen_in_csv(year, month, i+1)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "d9f3e24b",
   "metadata": {},
   "source": [
    "## Auswertung: Wie viele Einträge pro Bundesland?"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "9f600d3c",
   "metadata": {},
   "source": [
    "Für fortführende Visualisierung und um zu testen, ob der Algorithmus richtig funktioniert, werden hier alle Pressemitteilungen aller Bundesländer ausgezählt:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "id": "b7c85078",
   "metadata": {},
   "outputs": [],
   "source": [
    "counter = {}\n",
    "\n",
    "for filename in os.listdir('../data/'):\n",
    "    if filename.endswith(\"_presseportal.csv\"):\n",
    "        path = '../data/' + filename\n",
    "        \n",
    "        with open(path, 'r', encoding='UTF8') as f_in:\n",
    "            reader = csv.reader(f_in)\n",
    "            next(reader)\n",
    "            for row in reader:\n",
    "                bundesland = row[3]\n",
    "                if bundesland not in counter:\n",
    "                    counter[bundesland] = 1\n",
    "                else:\n",
    "                    counter[bundesland] += 1\n"
   ]
  }
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