56 lines
1.5 KiB
Python
Executable File
56 lines
1.5 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Download flags of top 20 countries by population
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Sequential version
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Sample runs (first with new domain, so no caching ever)::
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$ ./flags.py
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BD BR CD CN DE EG ET FR ID IN IR JP MX NG PH PK RU TR US VN
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20 downloads in 26.21s
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$ ./flags.py
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BD BR CD CN DE EG ET FR ID IN IR JP MX NG PH PK RU TR US VN
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20 downloads in 14.57s
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"""
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# tag::FLAGS_PY[]
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import time
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from pathlib import Path
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from typing import Callable
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import requests # <1>
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POP20_CC = ('CN IN US ID BR PK NG BD RU JP '
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'MX PH VN ET EG DE IR TR CD FR').split() # <2>
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BASE_URL = 'http://fluentpython.com/data/flags' # <3>
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DEST_DIR = Path('downloaded') # <4>
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def save_flag(img: bytes, filename: str) -> None: # <5>
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(DEST_DIR / filename).write_bytes(img)
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def get_flag(cc: str) -> bytes: # <6>
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url = f'{BASE_URL}/{cc}/{cc}.gif'.lower()
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resp = requests.get(url)
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return resp.content
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def download_many(cc_list: list[str]) -> int: # <7>
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for cc in sorted(cc_list): # <8>
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image = get_flag(cc)
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save_flag(image, f'{cc}.gif')
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print(cc, end=' ', flush=True) # <9>
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return len(cc_list)
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def main(downloader: Callable[[list[str]], int]) -> None: # <10>
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t0 = time.perf_counter() # <11>
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count = downloader(POP20_CC)
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elapsed = time.perf_counter() - t0
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print(f'\n{count} downloads in {elapsed:.2f}s')
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if __name__ == '__main__':
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main(download_many) # <12>
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# end::FLAGS_PY[]
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