mirror of
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125 lines
4.3 KiB
Python
125 lines
4.3 KiB
Python
# coding=utf-8
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__all__ = ["Downloader"]
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import logging
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import traceback
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from concurrent.futures import ThreadPoolExecutor, TimeoutError, as_completed
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from os import environ, makedirs
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from os.path import exists, join
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from random import choice
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from time import time
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import requests
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from kivy.clock import Clock
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from kivy.logger import LOG_LEVELS, Logger
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from mapview.constants import CACHE_DIR
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# if "MAPVIEW_DEBUG_DOWNLOADER" in environ:
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# Logger.setLevel(LOG_LEVELS['debug'])
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Logger.setLevel(LOG_LEVELS['error'])
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# user agent is needed because since may 2019 OSM gives me a 429 or 403 server error
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# I tried it with a simpler one (just Mozilla/5.0) this also gets rejected
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USER_AGENT = 'Kivy-garden.mapview'
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class Downloader:
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_instance = None
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MAX_WORKERS = 5
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CAP_TIME = 0.064 # 15 FPS
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@staticmethod
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def instance(cache_dir=None):
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if Downloader._instance is None:
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if not cache_dir:
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cache_dir = CACHE_DIR
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Downloader._instance = Downloader(cache_dir=cache_dir)
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return Downloader._instance
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def __init__(self, max_workers=None, cap_time=None, **kwargs):
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self.cache_dir = kwargs.get('cache_dir', CACHE_DIR)
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if max_workers is None:
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max_workers = Downloader.MAX_WORKERS
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if cap_time is None:
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cap_time = Downloader.CAP_TIME
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self.is_paused = False
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self.cap_time = cap_time
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self.executor = ThreadPoolExecutor(max_workers=max_workers)
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self._futures = []
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Clock.schedule_interval(self._check_executor, 1 / 60.0)
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if not exists(self.cache_dir):
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makedirs(self.cache_dir)
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def submit(self, f, *args, **kwargs):
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future = self.executor.submit(f, *args, **kwargs)
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self._futures.append(future)
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def download_tile(self, tile):
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# Logger.debug(
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# "Downloader: queue(tile) zoom={} x={} y={}".format(
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# tile.zoom, tile.tile_x, tile.tile_y
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# )
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# )
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future = self.executor.submit(self._load_tile, tile)
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self._futures.append(future)
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def download(self, url, callback, **kwargs):
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# Logger.debug("Downloader: queue(url) {}".format(url))
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future = self.executor.submit(self._download_url, url, callback, kwargs)
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self._futures.append(future)
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def _download_url(self, url, callback, kwargs):
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# Logger.debug("Downloader: download(url) {}".format(url))
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response = requests.get(url, **kwargs)
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response.raise_for_status()
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return callback, (url, response)
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def _load_tile(self, tile):
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if tile.state == "done":
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return
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cache_fn = tile.cache_fn
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if exists(cache_fn):
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# Logger.debug("Downloader: use cache {}".format(cache_fn))
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return tile.set_source, (cache_fn,)
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tile_y = tile.map_source.get_row_count(tile.zoom) - tile.tile_y - 1
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uri = tile.map_source.url.format(
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z=tile.zoom, x=tile.tile_x, y=tile_y, s=choice(tile.map_source.subdomains)
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)
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# Logger.debug("Downloader: download(tile) {}".format(uri))
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response = requests.get(uri, headers={'User-agent': USER_AGENT}, timeout=5)
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try:
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response.raise_for_status()
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data = response.content
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with open(cache_fn, "wb") as fd:
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fd.write(data)
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# Logger.debug("Downloaded {} bytes: {}".format(len(data), uri))
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return tile.set_source, (cache_fn,)
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except Exception as e:
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print("Downloader error: {!r}".format(e))
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def _check_executor(self, dt):
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start = time()
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try:
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for future in as_completed(self._futures[:], 0):
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self._futures.remove(future)
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try:
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result = future.result()
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except Exception:
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traceback.print_exc()
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# make an error tile?
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continue
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if result is None:
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continue
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callback, args = result
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callback(*args)
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# capped executor in time, in order to prevent too much
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# slowiness.
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# seems to works quite great with big zoom-in/out
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if time() - start > self.cap_time:
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break
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except TimeoutError:
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pass
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