41 lines
1.0 KiB
Python
41 lines
1.0 KiB
Python
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import os
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import hashlib
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import urllib.request
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def file_md5(path):
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"""Calculate the MD5 checksum of a file and return it in hexadecimal notation."""
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with open(path, 'rb') as f:
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m = hashlib.md5()
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while True:
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data = f.read(65536)
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if len(data) == 0:
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# end of file
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return m.hexdigest()
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m.update(data)
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def download_and_verify(url, md5, parent_path):
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"""Download a file, verify its MD5 checksum and return the local path."""
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os.makedirs(parent_path, exist_ok=True)
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path = os.path.join(parent_path, os.path.basename(url))
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try:
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calculated_md5 = file_md5(path)
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if md5 == calculated_md5: return path
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os.unlink(path)
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except FileNotFoundError:
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pass
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tmp_path = path + '.tmp'
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print("download", url)
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urllib.request.urlretrieve(url, tmp_path)
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calculated_md5 = file_md5(tmp_path)
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if calculated_md5 != md5:
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os.unlink(tmp_path)
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raise "MD5 mismatch"
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os.rename(tmp_path, path)
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return path
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