common/python/rift/downloader/base.py

   1 #
   2 #   Copyright 2016 RIFT.IO Inc
   3 #
   4 #   Licensed under the Apache License, Version 2.0 (the "License");
   5 #   you may not use this file except in compliance with the License.
   6 #   You may obtain a copy of the License at
   7 #
   8 #       http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 #   Unless required by applicable law or agreed to in writing, software
  11 #   distributed under the License is distributed on an "AS IS" BASIS,
  12 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 #   See the License for the specific language governing permissions and
  14 #   limitations under the License.
  15 #
  16 # Author(s): Varun Prasad
  17 # Creation Date: 09/25/2016
  18 #
  19
  20 import abc
  21 import enum
  22 import os
  23 import uuid
  24 import time
  25
  26
  27 class InvalidDestinationError(Exception):
  28     pass
  29
  30
  31 class DownloaderProtocol:
  32     """Listener of this class can implement the following method to get a
  33     callback
  34     """
  35     def on_download_started(self, job):
  36         """Called when the download starts
  37
  38         Args:
  39             job (DownloadJob): Yang Model
  40
  41         """
  42         pass
  43
  44     def on_download_progress(self, job):
  45         """Called after each chunk is downloaded
  46
  47         Args:
  48             job (DownloadJob): Yang Model
  49
  50         """
  51         pass
  52
  53     def on_download_succeeded(self, job):
  54         """Called when the download is completed successfully
  55
  56         Args:
  57             job (DownloadJob): Yang Model
  58
  59         """
  60         pass
  61
  62     def on_download_failed(self, job):
  63         """Called when the download fails
  64
  65         Args:
  66             job (DownloadJob): Yang Model
  67
  68         """
  69         pass
  70
  71     def on_download_cancelled(self, job):
  72         """Called when the download is canceled
  73
  74         Args:
  75             job (DownloadJob): Yang Model
  76
  77         """
  78         pass
  79
  80     def on_download_finished(self, job):
  81         """Called when the download finishes regardless of the status of the
  82         download (success, failed or canceled)
  83
  84         Args:
  85             job (DownloadJob): Yang Model
  86
  87         """
  88         pass
  89
  90
  91 class DownloadStatus(enum.Enum):
  92     STARTED = 1
  93     IN_PROGRESS = 2
  94     COMPLETED = 3
  95     FAILED = 4
  96     CANCELLED = 5
  97
  98
  99 class DownloadMeta:
 100     """Model data used by the downloader.
 101     """
 102     def __init__(self, url, dest_file):
 103         self.url = url
 104         self.filepath = dest_file
 105         self.download_id = str(uuid.uuid4())
 106         self.bytes_total = 0
 107         self.progress_percent = 0
 108         self.bytes_downloaded = 0
 109         self.bytes_per_second = 0
 110         self.status = None
 111         self.start_time = 0
 112         self.stop_time = 0
 113         self.detail = ""
 114
 115     @property
 116     def filename(self):
 117         return os.path.basename(self.filepath)
 118
 119     def start_download(self):
 120         self.start_time = time.time()
 121
 122     def end_download(self):
 123         self.end_time = time.time()
 124
 125     def set_state(self, state):
 126         self.status = state
 127
 128     def update_with_data(self, downloaded_chunk):
 129         self.bytes_downloaded += len(downloaded_chunk)
 130
 131         if self.bytes_total != 0:
 132             self.progress_percent = \
 133                 int((self.bytes_downloaded / self.bytes_total) * 100)
 134
 135         # compute bps
 136         seconds_elapsed = time.time() - self.start_time
 137         self.bytes_per_second = self.bytes_downloaded // seconds_elapsed
 138
 139     def update_data_with_head(self, headers):
 140         """Update the model from the header of HEAD request
 141
 142         Args:
 143             headers (dict): headers from HEAD response
 144         """
 145         if 'Content-Length' in headers:
 146             self.bytes_total = int(headers['Content-Length'])
 147
 148     def as_dict(self):
 149         return self.__dict__
 150
 151
 152 class AbstractDownloader:
 153
 154     def __init__(self):
 155         self._delegate = None
 156
 157     @property
 158     def delegate(self):
 159         return self._delegate
 160
 161     @delegate.setter
 162     def delegate(self, delegate):
 163         self._delegate = delegate
 164
 165     @abc.abstractproperty
 166     def download_id(self):
 167         pass
 168
 169     @abc.abstractmethod
 170     def cancel_download(self):
 171         pass
 172
 173     @abc.abstractmethod
 174     def close(self):
 175         pass
 176
 177     @abc.abstractmethod
 178     def download(self):
 179         pass