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
 111
 112         self.start_time = 0
 113         self.stop_time = 0
 114         self.detail = ""
 115
 116     @property
 117     def filename(self):
 118         return os.path.basename(self.filepath)
 119
 120     def start_download(self):
 121         self.start_time = time.time()
 122
 123     def end_download(self):
 124         self.end_time = time.time()
 125
 126     def set_state(self, state):
 127         self.status = state
 128
 129     def update_with_data(self, downloaded_chunk):
 130         self.bytes_downloaded += len(downloaded_chunk)
 131
 132         if self.bytes_total != 0:
 133             self.progress_percent = \
 134                 int((self.bytes_downloaded / self.bytes_total) * 100)
 135
 136         # compute bps
 137         seconds_elapsed = time.time() - self.start_time
 138         self.bytes_per_second = self.bytes_downloaded // seconds_elapsed
 139
 140     def update_data_with_head(self, headers):
 141         """Update the model from the header of HEAD request
 142
 143         Args:
 144             headers (dict): headers from HEAD response
 145         """
 146         if 'Content-Length' in headers:
 147             self.bytes_total = int(headers['Content-Length'])
 148
 149     def as_dict(self):
 150         return self.__dict__
 151
 152
 153 class AbstractDownloader:
 154
 155     def __init__(self):
 156         self._delegate = None
 157
 158     @property
 159     def delegate(self):
 160         return self._delegate
 161
 162     @delegate.setter
 163     def delegate(self, delegate):
 164         self._delegate = delegate
 165
 166     @abc.abstractproperty
 167     def download_id(self):
 168         pass
 169
 170     @abc.abstractmethod
 171     def cancel_download(self):
 172         pass
 173
 174     @abc.abstractmethod
 175     def close(self):
 176         pass
 177
 178     @abc.abstractmethod
 179     def download(self):
 180         pass