keyname 0.5.4

Easily pack and unpack metadata in a filename.

keyname

Easily pack and unpack metadata in a filename.

• Free software: MIT license

• Documentation: https://keyname.readthedocs.io.

Usage

Keyname is built around the following file name convention:

• key/value pairs are constructed with = between the key and value

• key/value pairs are joined by +

• key/value pairs are ordered alphanumerically by key

  • keys beginning with _ are ordered after keys not beginning with _

  • the ext (extension) key is always placed last

  • the key _ is reserved for the original filename

For example, key1=val1+key2=val2+_key3=val3+ext=.txt.

from keyname import keyname as kn

# returns 'key1=val1+key2=val2+_key3=val3+ext=.txt'
kn.pack({
  'key2' : 'val2',
  'ext' : '.txt',
  'key1' : 'val1',
  '_key3' : 'val3',
})

# returns {'key' : 'val', 'ext' : '.txt', '_' : 'path/to/key=val+ext=.txt'}
kf.unpack('path/to/key=val+ext=.txt')

Most operating systems only allow filename lengths of up to 255 characters. (And in Docker containers, the limit is sometimes 224 characters.) Trying to use longer filenames will fail.

Keyname provides tools to work around this restriction by chunking overlength filenames into nested directories and a file. (Basically, using the path to store the filename.) Path segments with continuations are denoted with the suffix “…”.

from pathlib import Path

from keyname import keyname as kn

# returns 'key0=val0+key1=val1+key10=val10+key11=val11+key12=val12+key13=val13+key14=val14+key15=val15+key16=val16+key17=val17+key18=val18+key19=val19+key2=val2+key20=val20+key21=val21+key22=val22+key23=val23+key24=val24+key25=val25+key26=val26+key27=val27+key28=val28+key29=val29+key3=val3+key30=val30+key31=val31+key32=val32+key33=val33+key34=val34+key35=val35+key36=val36+key37=val37+key38=val38+key39=val39+key4=val4+key40=val40+key41=val41+key42=val42+key43=val43+key44=val44+key45=val45+key46=val46+key47=val47+key48=val48+key49=val49+key5=val5+key50=val50+key51=val51+key52=val52+key53=val53+key54=val54+key55=val55+key56=val56+key57=val57+key58=val58+key59=val59+key6=val6+key60=val60+key61=val61+key62=val62+key63=val63+key64=val64+key65=val65+key66=val66+key67=val67+key68=val68+key69=val69+key7=val7+key70=val70+key71=val71+key72=val72+key73=val73+key74=val74+key75=val75+key76=val76+key77=val77+key78=val78+key79=val79+key8=val8+key80=val80+key81=val81+key82=val82+key83=val83+key84=val84+key85=val85+key86=val86+key87=val87+key88=val88+key89=val89+key9=val9+key90=val90+key91=val91+key92=val92+key93=val93+key94=val94+key95=val95+key96=val96+key97=val97+key98=val98+key99=val99'
packed = kn.pack({
  f'key{i}' : f'val{i}'
  for i in range(100)
})

# returns '/tmp/example/key0=val0+key1=val1+key10=val10+key11=val11+key12=val12+key13=val13+key14=val14+key15=val15+key16=val16+key17=val17+key18=val18+key19=val19+key2=val2+key20=val20+key21=val21+key22=val22+key23=val23+ke.../y24=val24+key25=val25+key26=val26+key27=val27+key28=val28+key29=val29+key3=val3+key30=val30+key31=val31+key32=val32+key33=val33+key34=val34+key35=val35+key36=val36+key37=val37+key38=val38+key39=val39+.../key4=val4+key40=val40+key41=val41+key42=val42+key43=val43+key44=val44+key45=val45+key46=val46+key47=val47+key48=val48+key49=val49+key5=val5+key50=val50+key51=val51+key52=val52+key53=val53+key54=val54+.../key55=val55+key56=val56+key57=val57+key58=val58+key59=val59+key6=val6+key60=val60+key61=val61+key62=val62+key63=val63+key64=val64+key65=val65+key66=val66+key67=val67+key68=val68+key69=val69+key7=val7+.../key70=val70+key71=val71+key72=val72+key73=val73+key74=val74+key75=val75+key76=val76+key77=val77+key78=val78+key79=val79+key8=val8+key80=val80+key81=val81+key82=val82+key83=val83+key84=val84+key85=val8.../5+key86=val86+key87=val87+key88=val88+key89=val89+key9=val9+key90=val90+key91=val91+key92=val92+key93=val93+key94=val94+key95=val95+key96=val96+key97=val97+key98=val98+key99=val99'
chopped = kn.chop(f'/tmp/example/{packed}', mkdir=True)

# works
Path(chopped).touch()

# returns {'key0': 'val0', 'key1': 'val1', 'key10': 'val10', 'key11': 'val11', 'key12': 'val12', 'key13': 'val13', 'key14': 'val14', 'key15': 'val15', 'key16': 'val16', 'key17': 'val17', 'key18': 'val18', 'key19': 'val19', 'key2': 'val2', 'key20': 'val20', 'key21': 'val21', 'key22': 'val22', 'key23': 'val23', 'key24': 'val24', 'key25': 'val25', 'key26': 'val26', 'key27': 'val27', 'key28': 'val28', 'key29': 'val29', 'key3': 'val3', 'key30': 'val30', 'key31': 'val31', 'key32': 'val32', 'key33': 'val33', 'key34': 'val34', 'key35': 'val35', 'key36': 'val36', 'key37': 'val37', 'key38': 'val38', 'key39': 'val39', 'key4': 'val4', 'key40': 'val40', 'key41': 'val41', 'key42': 'val42', 'key43': 'val43', 'key44': 'val44', 'key45': 'val45', 'key46': 'val46', 'key47': 'val47', 'key48': 'val48', 'key49': 'val49', 'key5': 'val5', 'key50': 'val50', 'key51': 'val51', 'key52': 'val52', 'key53': 'val53', 'key54': 'val54', 'key55': 'val55', 'key56': 'val56', 'key57': 'val57', 'key58': 'val58', 'key59': 'val59', 'key6': 'val6', 'key60': 'val60', 'key61': 'val61', 'key62': 'val62', 'key63': 'val63', 'key64': 'val64', 'key65': 'val65', 'key66': 'val66', 'key67': 'val67', 'key68': 'val68', 'key69': 'val69', 'key7': 'val7', 'key70': 'val70', 'key71': 'val71', 'key72': 'val72', 'key73': 'val73', 'key74': 'val74', 'key75': 'val75', 'key76': 'val76', 'key77': 'val77', 'key78': 'val78', 'key79': 'val79', 'key8': 'val8', 'key80': 'val80', 'key81': 'val81', 'key82': 'val82', 'key83': 'val83', 'key84': 'val84', 'key85': 'val85', 'key86': 'val86', 'key87': 'val87', 'key88': 'val88', 'key89': 'val89', 'key9': 'val9', 'key90': 'val90', 'key91': 'val91', 'key92': 'val92', 'key93': 'val93', 'key94': 'val94', 'key95': 'val95', 'key96': 'val96', 'key97': 'val97', 'key98': 'val98', 'key99': 'val99', '_': '/tmp/example/key0=val0+key1=val1+key10=val10+key11=val11+key12=val12+key13=val13+key14=val14+key15=val15+key16=val16+key17=val17+key18=val18+key19=val19+key2=val2+key20=val20+key21=val21+key22=val22+key23=val23+key24=val24+key25=val25+key26=val26+key27=val27+key28=val28+key29=val29+key3=val3+key30=val30+key31=val31+key32=val32+key33=val33+key34=val34+key35=val35+key36=val36+key37=val37+key38=val38+key39=val39+key4=val4+key40=val40+key41=val41+key42=val42+key43=val43+key44=val44+key45=val45+key46=val46+key47=val47+key48=val48+key49=val49+key5=val5+key50=val50+key51=val51+key52=val52+key53=val53+key54=val54+key55=val55+key56=val56+key57=val57+key58=val58+key59=val59+key6=val6+key60=val60+key61=val61+key62=val62+key63=val63+key64=val64+key65=val65+key66=val66+key67=val67+key68=val68+key69=val69+key7=val7+key70=val70+key71=val71+key72=val72+key73=val73+key74=val74+key75=val75+key76=val76+key77=val77+key78=val78+key79=val79+key8=val8+key80=val80+key81=val81+key82=val82+key83=val83+key84=val84+key85=val85+key86=val86+key87=val87+key88=val88+key89=val89+key9=val9+key90=val90+key91=val91+key92=val92+key93=val93+key94=val94+key95=val95+key96=val96+key97=val97+key98=val98+key99=val99'}
kn.unpack(kn.rejoin(chopped))

$ tree /tmp/example
/tmp/example
└── key0=val0+key1=val1+key10=val10+key11=val11+key12=val12+key13=val13+key14=val14+key15=val15+key16=val16+key17=val17+key18=val18+key19=val19+key2=val2+key20=val20+key21=val21+key22=val22+key23=val23+ke...
    └── y24=val24+key25=val25+key26=val26+key27=val27+key28=val28+key29=val29+key3=val3+key30=val30+key31=val31+key32=val32+key33=val33+key34=val34+key35=val35+key36=val36+key37=val37+key38=val38+key39=val39+...
        └── key4=val4+key40=val40+key41=val41+key42=val42+key43=val43+key44=val44+key45=val45+key46=val46+key47=val47+key48=val48+key49=val49+key5=val5+key50=val50+key51=val51+key52=val52+key53=val53+key54=val54+...
            └── key55=val55+key56=val56+key57=val57+key58=val58+key59=val59+key6=val6+key60=val60+key61=val61+key62=val62+key63=val63+key64=val64+key65=val65+key66=val66+key67=val67+key68=val68+key69=val69+key7=val7+...
                └── key70=val70+key71=val71+key72=val72+key73=val73+key74=val74+key75=val75+key76=val76+key77=val77+key78=val78+key79=val79+key8=val8+key80=val80+key81=val81+key82=val82+key83=val83+key84=val84+key85=val8...
                    └── 5+key86=val86+key87=val87+key88=val88+key89=val89+key9=val9+key90=val90+key91=val91+key92=val92+key93=val93+key94=val94+key95=val95+key96=val96+key97=val97+key98=val98+key99=val99

Credits

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.

History

0.0.0 (2019-03-16)

• First release on PyPI.