Merge pull request #3 from netzbegruenung/python-service

Python webservice to support digital signage HTML/JS apps
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@ -30,6 +30,12 @@ kostenlos. Damit eignet sich Yodeck evtl. für kleine Büros.
### Screenly
OpenSource alternative zu Yodeck. Sollte ähnlichen Umfang haben wie Yodeck, aber durch OS flexibler.
Beschreibung folgt.
Beschreibung folgt.
https://www.screenly.io/ose/
## Software
Im Unterordner `service` entsteht Software zur Erzeugung dynamischer
HTML-Inhalte, die für Digital Signage eingesetzt werden können. Dokumentation
folgt, sobald diese Software einsatzfähig ist.

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service/.gitignore vendored Normal file
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venv
.pytest_cache
*.pyc

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service/Dockerfile Normal file
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FROM python:3.6-alpine3.6
WORKDIR /app
COPY . /app
RUN pip install -r requirements.txt
EXPOSE 5000
ENTRYPOINT ["gunicorn", "--bind=0.0.0.0:5000", "api.main:app"]

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service/Makefile Normal file
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serve:
gunicorn --reload -b 0.0.0.0:5000 api.main:app
test:
pytest tests

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service/README.md Normal file
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# Schaufenster Service
Dies ist ein Webservice zur Erzeugung dynamischer Inhalte für
Digital Signage Anwendungen.
_Anwendungsbeispiel:_
Auf einer digitalen Anzeigetafel soll stets aktuell der nächste Sitzungstermin
angezeigt werden. Hierfür geben wir eine iCal-Kalender-URL an
und bekommen dafür Titel und weitere Details der nächsten Termine in diesem
Kalender zurück.
## API
### `GET /events/` - Die nächsten Termine eines iCal Kalenders ausgeben
Request URL Parameter:
- `ical_url`: Adresse des iCal-Kalenders (erforderlich).
- `num`: Maximale Anzahl der Termine, die ausgegeben werden.
- `charset`: Zeichensatz der iCal-Quelle. Normalerweise wird der Zeichensatz
angenommen, den der Webserver im `Content-type` header angibt. Mit diesem
Parameter kann der Wert des Servers überschrieben werden. Beispiel: `charset=utf-8`.
Ausgabe:
```json
[
{
"title": "Karfreitag",
"start": "2018-03-30",
"end": "2018-03-31"
},
...
]
```
Liste mit Terminen als JSON Array. Jeder Termin enthält:
- `title`: Titel des Termins
- `start`: Start-Datum (oder Datum/Uhrzeit) des Termins
- `end`: (optional) Enddatum (oder Datum/Uhrzeit) des Termins
Beispiele:
- [Der nächste Termin beim Grünen Ortsverband Rösrath](https://schaufenster-service.now.sh/events/?charset=utf8&num=1&ical_url=https%3A%2F%2Fgruene-roesrath.de%2Ftermine%2Fcal%2Fics%2F%3Ftype%3D150%26tx_cal_controller%255Bcalendar%255D%3D649)
- [Die nächsten 3 Feiertage in Deutschland](https://schaufenster-service.now.sh/events/?num=3&ical_url=http%3A%2F%2Fwww.webcal.fi%2Fcal.php%3Fid%3D75%26rid%3Dics%26wrn%3D0%26wp%3D12%26wf%3D55)
### Live Demo
Der Service ist erreichbar unter https://schaufenster-service.now.sh/events/
### `GET /luftdaten.info/v1/sensor/{sensor_id}/` - Aktuelle Messwerte eines luftdaten.info Sensors ausgeben
Mit dieser Methode können Feinstaub-Messwerte eines luftdaten.info Sensors
abgerufen werden.
Beispiel:
- https://schaufenster-service.now.sh/luftdateninfo/v1/sensor/6316/

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service/api/__init__.py Normal file
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service/api/events.py Normal file
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# -*- coding: utf-8 -*-
import requests
import icalendar
from datetime import datetime
from datetime import date
class Client(object):
def __init__(self, url, charset=None):
self.url = url
self.charset = charset
self.events = []
self.timeout = 20
self.__load()
def __load(self):
r = requests.get(self.url, timeout=self.timeout)
r.raise_for_status()
# requests normally uses encoding returned by "Content-type" header.
# If charset is set, this overwrites the detected character encoding.
if self.charset is not None:
r.encoding = self.charset
cal = icalendar.Calendar.from_ical(r.text)
self.events = []
for event in cal.walk('vevent'):
title = None
if "SUMMARY" in event:
title = event["SUMMARY"]
dtstart = event["DTSTART"].dt
dtend = event["DTEND"].dt
self.events.append({
"title": title,
"start": dtstart,
"end": dtend,
})
# sort events by start datetime
def getdatetime(event):
if isinstance(event["start"], date):
return datetime.combine(event["start"], datetime.min.time())
return event["start"]
self.events = sorted(self.events, key=getdatetime)
def next_events(self, num=10):
"""
Returns the next num events from the calendar
"""
now = datetime.utcnow()
out = []
for event in self.events:
end = event["end"]
if isinstance(end, date):
end = datetime.combine(end, datetime.min.time())
if end > now:
out.append(event)
if len(out) >= num:
break
return out

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import six
from datetime import date, datetime
from falcon import errors
from falcon.media import BaseHandler
from falcon.util import json
class ComplexEncoder(json.JSONEncoder):
"""JSONENcoder that handles date and datetime"""
def default(self, obj):
if isinstance(obj, date) or isinstance(obj, datetime):
return obj.isoformat()
# Let the base class default method raise the TypeError
return json.JSONEncoder.default(self, obj)
class JSONHandler(BaseHandler):
"""Handler built using Python's :py:mod:`json` module."""
def deserialize(self, raw):
try:
return json.loads(raw.decode('utf-8'))
except ValueError as err:
raise errors.HTTPBadRequest(
'Invalid JSON',
'Could not parse JSON body - {0}'.format(err)
)
def serialize(self, media):
result = json.dumps(media,
ensure_ascii=False,
cls=ComplexEncoder)
if six.PY3 or not isinstance(result, bytes):
return result.encode('utf-8')
return result

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service/api/main.py Normal file
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# -*- coding: utf-8 -*-
from . import events
from . import jsonhandler
from datetime import datetime
from falcon import media
from falcon_cors import CORS
import falcon
import logging
import requests
class EventsResource(object):
def __init__(self):
self.logger = logging.getLogger('api.' + __name__)
def on_get(self, req, resp):
"""
Loads an ical Calendar and returns the next events
"""
ical_url = req.get_param("ical_url", required=True)
charset = req.get_param("charset")
num = int(req.get_param("num", required=False, default="10"))
client = events.Client(url=ical_url, charset=charset)
next_events = client.next_events(num)
del client
resp.media = next_events
maxage = 60 * 60 # 1 hour
resp.cache_control = ["max_age=%d" % maxage]
class ParticleSensorResource(object):
def on_get(self, req, resp, sensor_id):
"""
Delivers data for a particular luftdaten.info sensor
"""
url = "http://api.luftdaten.info/v1/sensor/%s/" % sensor_id
r = requests.get(url)
if r.status_code == 200:
maxage = 60 * 5 # 5 minutes
resp.cache_control = ["max_age=%d" % maxage]
resp.media = r.json()
else:
resp.media = r.text
resp.status = str(r.status_code) + " Unknown Error"
handlers = media.Handlers({
'application/json': jsonhandler.JSONHandler(),
})
cors = CORS(allow_all_origins=True,
allow_all_headers=True)
app = falcon.API(middleware=[cors.middleware])
app.req_options.media_handlers = handlers
app.resp_options.media_handlers = handlers
app.add_route('/events/', EventsResource())
app.add_route('/luftdaten.info/v1/sensor/{sensor_id}/', ParticleSensorResource())

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service/requirements.txt Normal file
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attrs==17.4.0
certifi==2018.1.18
chardet==3.0.4
falcon==1.4.1
falcon-cors==1.1.7
funcsigs==1.0.2
gunicorn==19.7.1
icalendar==4.0.0
idna==2.6
pluggy==0.6.0
py==1.5.2
pytest==3.4.0
python-dateutil==2.6.1
python-mimeparse==1.6.0
pytz==2017.3
requests==2.18.4
six==1.11.0
urllib3==1.22

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import falcon
from falcon import testing
import pytest
from api.main import app
@pytest.fixture
def client():
return testing.TestClient(app)
def test_get_events_no_ical_url(client):
"""
No ical URL given bad request
"""
response = client.simulate_get('/events/')
assert response.status == falcon.HTTP_BAD_REQUEST
# TODO: assertion for response format
def test_get_events(client):
response = client.simulate_get('/events/', params={
"ical_url": "http://www.webcal.fi/cal.php?id=75&rid=ics&wrn=0&wp=12&wf=55"
})
assert response.status == falcon.HTTP_OK