apps/sorl/thumbnail/utils.py

   1 import math
   2 import os
   3 import re
   4
   5
   6 re_thumbnail_file = re.compile(r'(?P<source_filename>.+)_(?P<x>\d+)x(?P<y>\d+)'
   7                                r'(?:_(?P<options>\w+))?_q(?P<quality>\d+)'
   8                                r'(?:.[^.]+)?$')
   9 re_new_args = re.compile('(?<!quality)=')
  10
  11
  12 def all_thumbnails(path, recursive=True, prefix=None, subdir=None):
  13     """
  14     Return a dictionary referencing all files which match the thumbnail format.
  15
  16     Each key is a source image filename, relative to path.
  17     Each value is a list of dictionaries as explained in `thumbnails_for_file`.
  18     """
  19     # Fall back to using thumbnail settings. These are local imports so that
  20     # there is no requirement of Django to use the utils module.
  21     if prefix is None:
  22         from sorl.thumbnail.main import get_thumbnail_setting
  23         prefix = get_thumbnail_setting('PREFIX')
  24     if subdir is None:
  25         from sorl.thumbnail.main import get_thumbnail_setting
  26         subdir = get_thumbnail_setting('SUBDIR')
  27     thumbnail_files = {}
  28     if not path.endswith('/'):
  29         path = '%s/' % path
  30     len_path = len(path)
  31     if recursive:
  32         all = os.walk(path)
  33     else:
  34         files = []
  35         for file in os.listdir(path):
  36             if os.path.isfile(os.path.join(path, file)):
  37                 files.append(file)
  38         all = [(path, [], files)]
  39     for dir_, subdirs, files in all:
  40         rel_dir = dir_[len_path:]
  41         for file in files:
  42             thumb = re_thumbnail_file.match(file)
  43             if not thumb:
  44                 continue
  45             d = thumb.groupdict()
  46             source_filename = d.pop('source_filename')
  47             if prefix:
  48                 source_path, source_filename = os.path.split(source_filename)
  49                 if not source_filename.startswith(prefix):
  50                     continue
  51                 source_filename = os.path.join(source_path,
  52                     source_filename[len(prefix):])
  53             d['options'] = d['options'] and d['options'].split('_') or []
  54             if subdir and rel_dir.endswith(subdir):
  55                 rel_dir = rel_dir[:-len(subdir)]
  56             # Corner-case bug: if the filename didn't have an extension but did
  57             # have an underscore, the last underscore will get converted to a
  58             # '.'.
  59             m = re.match(r'(.*)_(.*)', source_filename)
  60             if m:
  61                 source_filename = '%s.%s' % m.groups()
  62             filename = os.path.join(rel_dir, source_filename)
  63             thumbnail_file = thumbnail_files.setdefault(filename, [])
  64             d['filename'] = os.path.join(dir_, file)
  65             thumbnail_file.append(d)
  66     return thumbnail_files
  67
  68
  69 def thumbnails_for_file(relative_source_path, root=None, basedir=None,
  70                         subdir=None, prefix=None):
  71     """
  72     Return a list of dictionaries, one for each thumbnail belonging to the
  73     source image.
  74
  75     The following list explains each key of the dictionary:
  76
  77       `filename`  -- absolute thumbnail path
  78       `x` and `y` -- the size of the thumbnail
  79       `options`   -- list of options for this thumbnail
  80       `quality`   -- quality setting for this thumbnail
  81     """
  82     # Fall back to using thumbnail settings. These are local imports so that
  83     # there is no requirement of Django to use the utils module.
  84     if root is None:
  85         from django.conf import settings
  86         root = settings.MEDIA_ROOT
  87     if prefix is None:
  88         from sorl.thumbnail.main import get_thumbnail_setting
  89         prefix = get_thumbnail_setting('PREFIX')
  90     if subdir is None:
  91         from sorl.thumbnail.main import get_thumbnail_setting
  92         subdir = get_thumbnail_setting('SUBDIR')
  93     if basedir is None:
  94         from sorl.thumbnail.main import get_thumbnail_setting
  95         basedir = get_thumbnail_setting('BASEDIR')
  96     source_dir, filename = os.path.split(relative_source_path)
  97     thumbs_path = os.path.join(root, basedir, source_dir, subdir)
  98     if not os.path.isdir(thumbs_path):
  99         return []
 100     files = all_thumbnails(thumbs_path, recursive=False, prefix=prefix,
 101                            subdir='')
 102     return files.get(filename, [])
 103
 104
 105 def delete_thumbnails(relative_source_path, root=None, basedir=None,
 106                       subdir=None, prefix=None):
 107     """
 108     Delete all thumbnails for a source image.
 109     """
 110     thumbs = thumbnails_for_file(relative_source_path, root, basedir, subdir,
 111                                  prefix)
 112     return _delete_using_thumbs_list(thumbs)
 113
 114
 115 def _delete_using_thumbs_list(thumbs):
 116     deleted = 0
 117     for thumb_dict in thumbs:
 118         filename = thumb_dict['filename']
 119         try:
 120             os.remove(filename)
 121         except:
 122             pass
 123         else:
 124             deleted += 1
 125     return deleted
 126
 127
 128 def delete_all_thumbnails(path, recursive=True):
 129     """
 130     Delete all files within a path which match the thumbnails pattern.
 131
 132     By default, matching files from all sub-directories are also removed. To
 133     only remove from the path directory, set recursive=False.
 134     """
 135     total = 0
 136     for thumbs in all_thumbnails(path, recursive=recursive).values():
 137         total += _delete_using_thumbs_list(thumbs)
 138     return total
 139
 140
 141 def split_args(args):
 142     """
 143     Split a list of argument strings into a dictionary where each key is an
 144     argument name.
 145
 146     An argument looks like ``crop``, ``crop="some option"`` or ``crop=my_var``.
 147     Arguments which provide no value get a value of ``None``.
 148     """
 149     if not args:
 150         return {}
 151     # Handle the old comma separated argument format.
 152     if len(args) == 1 and not re_new_args.search(args[0]):
 153         args = args[0].split(',')
 154     # Separate out the key and value for each argument.
 155     args_dict = {}
 156     for arg in args:
 157         split_arg = arg.split('=', 1)
 158         value = len(split_arg) > 1 and split_arg[1] or None
 159         args_dict[split_arg[0]] = value
 160     return args_dict
 161
 162
 163 def image_entropy(im):
 164     """
 165     Calculate the entropy of an image. Used for "smart cropping".
 166     """
 167     hist = im.histogram()
 168     hist_size = float(sum(hist))
 169     hist = [h / hist_size for h in hist]
 170     return -sum([p * math.log(p, 2) for p in hist if p != 0])