src/librarian/picture.py

   1 # -*- coding: utf-8 -*-
   2 from __future__ import unicode_literals
   3
   4 from operator import and_
   5
   6 from .dcparser import Field, WorkInfo, DCNS
   7 from librarian import (RDFNS, ValidationError, NoDublinCore, ParseError, WLURI)
   8 from xml.parsers.expat import ExpatError
   9 from os import path
  10 from lxml import etree
  11 from lxml.etree import (XMLSyntaxError, XSLTApplyError, Element)
  12 import re
  13 import six
  14
  15
  16 class WLPictureURI(WLURI):
  17     _re_wl_uri = re.compile(
  18         'http://wolnelektury.pl/katalog/obraz/(?P<slug>[-a-z0-9]+)/?$'
  19     )
  20     template = 'http://wolnelektury.pl/katalog/obraz/%s/'
  21
  22
  23 def as_wlpictureuri_strict(text):
  24     return WLPictureURI.strict(text)
  25
  26
  27 class PictureInfo(WorkInfo):
  28     """
  29     Dublin core metadata for a picture
  30     """
  31     FIELDS = (
  32         Field(DCNS('language'), 'language', required=False),
  33         Field(DCNS('subject.period'), 'epochs', salias='epoch', multiple=True),
  34         Field(DCNS('subject.type'), 'kinds', salias='kind', multiple=True),
  35         Field(DCNS('subject.genre'), 'genres', salias='genre', multiple=True,
  36               required=False),
  37         Field(DCNS('subject.style'), 'styles', salias='style', multiple=True,
  38               required=False),
  39
  40         Field(DCNS('format.dimensions'), 'dimensions', required=False),
  41         Field(DCNS('format.checksum.sha1'), 'sha1', required=True),
  42         Field(DCNS('description.medium'), 'medium', required=False),
  43         Field(DCNS('description.dimensions'), 'original_dimensions',
  44               required=False),
  45         Field(DCNS('format'), 'mime_type', required=False),
  46         Field(DCNS('identifier.url'), 'url', WLPictureURI,
  47               strict=as_wlpictureuri_strict)
  48     )
  49
  50
  51 class ImageStore(object):
  52     EXT = ['gif', 'jpeg', 'png', 'swf', 'psd', 'bmp'
  53            'tiff', 'tiff', 'jpc', 'jp2', 'jpf', 'jb2', 'swc',
  54            'aiff', 'wbmp', 'xbm']
  55     MIME = ['image/gif', 'image/jpeg', 'image/png',
  56             'application/x-shockwave-flash', 'image/psd', 'image/bmp',
  57             'image/tiff', 'image/tiff', 'application/octet-stream',
  58             'image/jp2', 'application/octet-stream',
  59             'application/octet-stream', 'application/x-shockwave-flash',
  60             'image/iff', 'image/vnd.wap.wbmp', 'image/xbm']
  61
  62     def __init__(self, dir_):
  63         super(ImageStore, self).__init__()
  64         self.dir = dir_
  65
  66     def path(self, slug, mime_type):
  67         """
  68         Finds file by slug and mime type in our iamge store.
  69         Returns a file objects (perhaps should return a filename?)
  70         """
  71         try:
  72             i = self.MIME.index(mime_type)
  73         except ValueError:
  74             err = ValueError(
  75                 "Picture %s has unknown mime type: %s"
  76                 % (slug, mime_type)
  77             )
  78             err.slug = slug
  79             err.mime_type = mime_type
  80             raise err
  81         ext = self.EXT[i]
  82         # add some common extensions tiff->tif, jpeg->jpg
  83         return path.join(self.dir, slug + '.' + ext)
  84
  85
  86 class WLPicture(object):
  87     def __init__(self, edoc, parse_dublincore=True, image_store=None):
  88         self.edoc = edoc
  89         self.image_store = image_store
  90
  91         root_elem = edoc.getroot()
  92
  93         dc_path = './/' + RDFNS('RDF')
  94
  95         if root_elem.tag != 'picture':
  96             raise ValidationError(
  97                 "Invalid root element. Found '%s', should be 'picture'"
  98                 % root_elem.tag
  99             )
 100
 101         if parse_dublincore:
 102             self.rdf_elem = root_elem.find(dc_path)
 103
 104             if self.rdf_elem is None:
 105                 raise NoDublinCore(
 106                     "Document has no DublinCore - which is required."
 107                 )
 108
 109             self.picture_info = PictureInfo.from_element(self.rdf_elem)
 110         else:
 111             self.picture_info = None
 112         self.frame = None
 113
 114     @classmethod
 115     def from_bytes(cls, xml, *args, **kwargs):
 116         return cls.from_file(six.BytesIO(xml), *args, **kwargs)
 117
 118     @classmethod
 119     def from_file(cls, xmlfile, parse_dublincore=True, image_store=None):
 120
 121         # first, prepare for parsing
 122         if isinstance(xmlfile, six.text_type):
 123             file = open(xmlfile, 'rb')
 124             try:
 125                 data = file.read()
 126             finally:
 127                 file.close()
 128         else:
 129             data = xmlfile.read()
 130
 131         if not isinstance(data, six.text_type):
 132             data = data.decode('utf-8')
 133
 134         data = data.replace(u'\ufeff', '')
 135
 136         # assume images are in the same directory
 137         if image_store is None and getattr(xmlfile, 'name', None):
 138             image_store = ImageStore(path.dirname(xmlfile.name))
 139
 140         try:
 141             parser = etree.XMLParser(remove_blank_text=False)
 142             tree = etree.parse(six.BytesIO(data.encode('utf-8')), parser)
 143
 144             me = cls(tree, parse_dublincore=parse_dublincore,
 145                      image_store=image_store)
 146             me.load_frame_info()
 147             return me
 148         except (ExpatError, XMLSyntaxError, XSLTApplyError) as e:
 149             raise ParseError(e)
 150
 151     @property
 152     def mime_type(self):
 153         if self.picture_info is None:
 154             raise ValueError(
 155                 "DC is not loaded, hence we don't know the image type."
 156             )
 157         return self.picture_info.mime_type
 158
 159     @property
 160     def slug(self):
 161         return self.picture_info.url.slug
 162
 163     @property
 164     def image_path(self):
 165         if self.image_store is None:
 166             raise ValueError("No image store associated with whis WLPicture.")
 167
 168         return self.image_store.path(self.slug, self.mime_type)
 169
 170     def image_file(self, *args, **kwargs):
 171         return open(self.image_path, 'rb', *args, **kwargs)
 172
 173     def get_sem_coords(self, sem):
 174         area = sem.find("div[@type='rect']")
 175         if area is None:
 176             area = sem.find("div[@type='whole']")
 177             return [[0, 0], [-1, -1]]
 178
 179         def has_all_props(node, props):
 180             return six.moves.reduce(
 181                 and_, map(lambda prop: prop in node.attrib, props)
 182             )
 183
 184         if not has_all_props(area, ['x1', 'x2', 'y1', 'y2']):
 185             return None
 186
 187         def n(prop): return int(area.get(prop))
 188         return [[n('x1'), n('y1')], [n('x2'), n('y2')]]
 189
 190     def partiter(self):
 191         """
 192         Iterates the parts of this picture and returns them
 193         and their metadata.
 194         """
 195         # omg no support for //sem[(@type='theme') or (@type='object')] ?
 196         for part in list(self.edoc.iterfind("//sem[@type='theme']")) +\
 197                 list(self.edoc.iterfind("//sem[@type='object']")):
 198             pd = {'type': part.get('type')}
 199
 200             coords = self.get_sem_coords(part)
 201             if coords is None:
 202                 continue
 203             pd['coords'] = coords
 204
 205             def want_unicode(x):
 206                 if not isinstance(x, six.text_type):
 207                     return x.decode('utf-8')
 208                 else:
 209                     return x
 210             pd['object'] = (
 211                 part.attrib['type'] == 'object'
 212                 and want_unicode(part.attrib.get('object', u''))
 213                 or None
 214             )
 215             pd['themes'] = (
 216                 part.attrib['type'] == 'theme'
 217                 and [part.attrib.get('theme', u'')]
 218                 or []
 219             )
 220             yield pd
 221
 222     def load_frame_info(self):
 223         k = self.edoc.find("//sem[@object='kadr']")
 224
 225         if k is not None:
 226             clip = self.get_sem_coords(k)
 227             self.frame = clip
 228             frm = Element("sem", {"type": "frame"})
 229             frm.append(next(k.iter("div")))
 230             self.edoc.getroot().append(frm)
 231             k.getparent().remove(k)
 232         else:
 233             frm = self.edoc.find("//sem[@type='frame']")
 234             if frm:
 235                 self.frame = self.get_sem_coords(frm)
 236             else:
 237                 self.frame = None
 238         return self