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1 import os |
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2 from os.path import join, normcase, normpath, abspath, isabs, sep |
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3 from django.utils.encoding import force_unicode |
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4 |
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5 # Define our own abspath function that can handle joining |
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6 # unicode paths to a current working directory that has non-ASCII |
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7 # characters in it. This isn't necessary on Windows since the |
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8 # Windows version of abspath handles this correctly. The Windows |
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9 # abspath also handles drive letters differently than the pure |
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10 # Python implementation, so it's best not to replace it. |
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11 if os.name == 'nt': |
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12 abspathu = abspath |
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13 else: |
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14 def abspathu(path): |
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15 """ |
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16 Version of os.path.abspath that uses the unicode representation |
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17 of the current working directory, thus avoiding a UnicodeDecodeError |
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18 in join when the cwd has non-ASCII characters. |
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19 """ |
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20 if not isabs(path): |
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21 path = join(os.getcwdu(), path) |
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22 return normpath(path) |
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23 |
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24 def safe_join(base, *paths): |
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25 """ |
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26 Joins one or more path components to the base path component intelligently. |
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27 Returns a normalized, absolute version of the final path. |
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28 |
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29 The final path must be located inside of the base path component (otherwise |
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30 a ValueError is raised). |
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31 """ |
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32 # We need to use normcase to ensure we don't false-negative on case |
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33 # insensitive operating systems (like Windows). |
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34 base = force_unicode(base) |
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35 paths = [force_unicode(p) for p in paths] |
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36 final_path = normcase(abspathu(join(base, *paths))) |
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37 base_path = normcase(abspathu(base)) |
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38 base_path_len = len(base_path) |
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39 # Ensure final_path starts with base_path and that the next character after |
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40 # the final path is os.sep (or nothing, in which case final_path must be |
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41 # equal to base_path). |
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42 if not final_path.startswith(base_path) \ |
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43 or final_path[base_path_len:base_path_len+1] not in ('', sep): |
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44 raise ValueError('the joined path is located outside of the base path' |
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45 ' component') |
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46 return final_path |