restpublish.py

   1 #!/usr/bin/env python3
   2 #
   3 # FLASK_APP=restpublish.py flask run
   4
   5 import datetime
   6
   7 import flask
   8 from flask_restful import Resource, Api
   9
  10
  11 class Element:
  12     def __init__(self, key, value):
  13         self.key = key
  14         self.update(value)
  15
  16     def update(self, value):
  17         self.value = value
  18         self.ctime = datetime.datetime.now()
  19
  20     def is_expired(self, maxage):
  21         return datetime.datetime.now() - self.ctime >= maxage
  22
  23
  24 class ElementStore:
  25     def __init__(self):
  26         self.key_dict = dict()
  27         self.chronolist = list()
  28
  29     def insert(self, key, value):
  30         if key in self.key_dict:
  31             el = self.key_dict[key]
  32             el.update(value)
  33         else:
  34             el = Element(key, value)
  35             self.key_dict[key] = el
  36             self.chronolist.append(el)
  37         return el
  38
  39     def remove(self, key):
  40         del self.key_dict[key]
  41         self.chronolist = [el for el in self.chronolist if el.key != key]
  42
  43     def garbagecollect(self):
  44         maxage = datetime.timedelta(7)
  45         oldestctime = datetime.datetime.now() - maxage
  46         def is_expired(el):
  47             return el.ctime < oldestctime
  48
  49         # Get idx such that self.chronolist[:idx] is expired and
  50         # self.chronolist[idx:] is not expired.
  51         idx = 0
  52         while idx < len(self.chronolist) - 1:
  53             if not is_expired(self.chronolist[idx]):
  54                 break
  55             idx += 1
  56
  57         for el in self.chronolist[:idx]:
  58             del self.key_dict[el.key]
  59
  60         self.chronolist = self.chronolist[idx:]
  61
  62
  63 class EntryPoint(Resource):
  64     def get(self):
  65         return { 'elements': [el.key for el in store.chronolist] }
  66
  67 class ElementPoint(Resource):
  68     def get(self, key):
  69         if key not in store.key_dict:
  70             return { 'message': 'No such element'}, 404
  71
  72         el = store.key_dict[key]
  73         return { 'key': key, 'value': el.value, 'ctime': str(el.ctime) }
  74
  75     def delete(self, key):
  76         if key in store.key_dict:
  77             store.remove(key)
  78         return { 'message': 'ok'}
  79
  80     def post(self, key):
  81         req = flask.request.get_json(force=True)
  82
  83         if 'value' not in req:
  84             return {'message': 'No value given.'}, 403
  85
  86         el = store.insert(key, req['value'])
  87         store.garbagecollect()
  88         return { 'key': key, 'value': el.value, 'ctime': str(el.ctime) }
  89
  90
  91 # Map of keys to values
  92 store = ElementStore()
  93
  94 app = flask.Flask(__name__)
  95 api = Api(app)
  96 api.add_resource(EntryPoint, "/")
  97 api.add_resource(ElementPoint, "/<key>")
  98