metadata.py

   1 # -*- coding: utf-8 -*-
   2 #######################################################################################
   3 #   Photo is a part of Plinn - http://plinn.org                                       #
   4 #   Copyright © 2004-2008  Benoît PIN <benoit.pin@ensmp.fr>                           #
   5 #                                                                                     #
   6 #   This program is free software; you can redistribute it and/or                     #
   7 #   modify it under the terms of the GNU General Public License                       #
   8 #   as published by the Free Software Foundation; either version 2                    #
   9 #   of the License, or (at your option) any later version.                            #
  10 #                                                                                     #
  11 #   This program is distributed in the hope that it will be useful,                   #
  12 #   but WITHOUT ANY WARRANTY; without even the implied warranty of                    #
  13 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                     #
  14 #   GNU General Public License for more details.                                      #
  15 #                                                                                     #
  16 #   You should have received a copy of the GNU General Public License                 #
  17 #   along with this program; if not, write to the Free Software                       #
  18 #   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.   #
  19 #######################################################################################
  20 """ Photo metadata read / write module
  21
  22
  23
  24 """
  25
  26 from AccessControl import ClassSecurityInfo
  27 from Acquisition import aq_base
  28 from Globals import InitializeClass
  29 from AccessControl.Permissions import view
  30 from ZODB.interfaces import BlobError
  31 from ZODB.utils import cp
  32 from OFS.Image import File
  33 from xmp import XMP
  34 from logging import getLogger
  35 from cache import memoizedmethod
  36 from libxml2 import parseDoc
  37 from standards.xmp import accessors as xmpAccessors
  38 import xmputils
  39 from types import TupleType
  40 from subprocess import Popen, PIPE
  41 from Products.PortalTransforms.libtransforms.utils import bin_search, \
  42                                                                                                                   MissingBinary
  43
  44 XPATH_EMPTY_TAGS = "//node()[name()!='' and not(node()) and not(@*)]"
  45 console = getLogger('Photo.metadata')
  46
  47 try :
  48         XMPDUMP = 'xmpdump'
  49         XMPLOAD = 'xmpload'
  50         bin_search(XMPDUMP)
  51         bin_search(XMPLOAD)
  52         xmpIO_OK = True
  53 except MissingBinary :
  54         xmpIO_OK = False
  55         console.warn("xmpdump or xmpload not available.")
  56
  57 class Metadata :
  58         """ Photo metadata read / write mixin """
  59
  60         security = ClassSecurityInfo()
  61
  62
  63         #
  64         # reading api
  65         #
  66
  67         security.declarePrivate('getXMP')
  68         if xmpIO_OK :
  69                 @memoizedmethod()
  70                 def getXMP(self):
  71                         """returns xmp metadata packet with xmpdump call
  72                         """
  73                         if self.size :
  74                                 blob_file_path = self.bdata._p_blob_uncommitted or self.bdata._p_blob_committed
  75                                 dumpcmd = '%s %s' % (XMPDUMP, blob_file_path)
  76                                 p = Popen(dumpcmd, stdout=PIPE, stderr=PIPE, stdin=PIPE, shell=True)
  77                                 xmp, err = p.communicate()
  78                                 if err :
  79                                         raise SystemError, err
  80                                 return xmp
  81
  82         else :
  83                 @memoizedmethod()
  84                 def getXMP(self):
  85                         """returns xmp metadata packet with XMP object
  86                         """
  87                         xmp = None
  88                         if self.size :
  89                                 try :
  90                                         bf = self.open('r')
  91                                         x = XMP(bf, content_type=self.content_type)
  92                                         xmp = x.getXMP()
  93                                 except NotImplementedError :
  94                                         pass
  95
  96                         return xmp
  97
  98         security.declareProtected(view, 'getXmpFile')
  99         def getXmpFile(self, REQUEST):
 100                 """returns the xmp packet over http.
 101                 """
 102                 xmp = self.getXMP()
 103                 if xmp is not None :
 104                         return File('xmp', 'xmp', xmp, content_type='text/xml').index_html(REQUEST, REQUEST.RESPONSE)
 105                 else :
 106                         return None
 107
 108         security.declarePrivate('getXmpBag')
 109         def getXmpBag(self, name, root, index=None) :
 110                 index = self.getXmpPathIndex()
 111                 if index :
 112                         path = '/'.join(filter(None, ['rdf:RDF/rdf:Description', root, name]))
 113                         node = index.get(path)
 114
 115                         if node :
 116                                 values = xmputils.getBagValues(node.element)
 117                                 return values
 118                 return tuple()
 119
 120         security.declarePrivate('getXmpSeq')
 121         def getXmpSeq(self, name, root) :
 122                 index = self.getXmpPathIndex()
 123                 if index :
 124                         path = '/'.join(filter(None, ['rdf:RDF/rdf:Description', root, name]))
 125                         node = index.get(path)
 126
 127                         if node :
 128                                 values = xmputils.getSeqValues(node.element)
 129                                 return values
 130                 return tuple()
 131
 132         security.declarePrivate('getXmpAlt')
 133         def getXmpAlt(self, name, root) :
 134                 index = self.getXmpPathIndex()
 135                 if index :
 136                         path = '/'.join(filter(None, ['rdf:RDF/rdf:Description', root, name]))
 137                         node = index.get(path)
 138
 139                         if node :
 140                                 firstLi = node.get('rdf:Alt/rdf:li')
 141                                 if firstLi :
 142                                         assert firstLi.unique, "More than one rdf:Alt (localisation not yet supported)"
 143                                         return firstLi.element.content
 144                 return ''
 145
 146         security.declarePrivate('getXmpProp')
 147         def getXmpProp(self, name, root):
 148                 index = self.getXmpPathIndex()
 149                 if index :
 150                         path = '/'.join(filter(None, ['rdf:RDF/rdf:Description', root, name]))
 151                         node = index.get(path)
 152                         if node :
 153                                 return node.element.content
 154                 return ''
 155
 156
 157         security.declarePrivate('getXmpPathIndex')
 158         @memoizedmethod(volatile=True)
 159         def getXmpPathIndex(self):
 160                 xmp = self.getXMP()
 161                 if xmp :
 162                         d = parseDoc(xmp)
 163                         index = xmputils.getPathIndex(d)
 164                         return index
 165
 166         security.declarePrivate('getXmpValue')
 167         def getXmpValue(self, name):
 168                 """ returns pythonic version of xmp property """
 169                 info = xmpAccessors[name]
 170                 root = info['root']
 171                 rdfType = info['rdfType'].capitalize()
 172                 methName = 'getXmp%s' % rdfType
 173                 meth = getattr(aq_base(self), methName)
 174                 return meth(name, root)
 175
 176
 177         security.declareProtected(view, 'getXmpField')
 178         def getXmpField(self, name):
 179                 """ returns data formated for a html form field """
 180                 editableValue = self.getXmpValue(name)
 181                 if type(editableValue) == TupleType :
 182                         editableValue = ', '.join(editableValue)
 183                 return {'id' : name.replace(':', '_'),
 184                                 'value' : editableValue}
 185
 186
 187         #
 188         # writing api
 189         #
 190
 191         security.declarePrivate('setXMP')
 192         if xmpIO_OK :
 193                 def setXMP(self, xmp):
 194                         """setXMP with xmpload call
 195                         """
 196                         if self.size :
 197                                 blob = self.bdata
 198                                 if blob.readers :
 199                                         raise BlobError("Already opened for reading.")
 200
 201                                 if blob._p_blob_uncommitted is None:
 202                                         filename = blob._create_uncommitted_file()
 203                                         uncommitted = file(filename, 'w')
 204                                         cp(file(blob._p_blob_committed, 'rb'), uncommitted)
 205                                         uncommitted.close()
 206                                 else :
 207                                         filename = blob._p_blob_uncommitted
 208
 209                                 loadcmd = '%s %s' % (XMPLOAD, filename)
 210                                 p = Popen(loadcmd, stdin=PIPE, stderr=PIPE, shell=True)
 211                                 p.stdin.write(xmp)
 212                                 p.stdin.close()
 213                                 p.wait()
 214                                 err = p.stderr.read()
 215                                 if err :
 216                                         raise SystemError, err
 217
 218                                 f = file(filename)
 219                                 f.seek(0,2)
 220                                 self.updateSize(size=f.tell())
 221                                 f.close()
 222                                 self.bdata._p_changed = True
 223
 224
 225                                 # purge caches
 226                                 try : del self._methodResultsCache['getXMP']
 227                                 except KeyError : pass
 228
 229                                 for name in ('getXmpPathIndex',) :
 230                                         try :
 231                                                 del self._v__methodResultsCache[name]
 232                                         except (AttributeError, KeyError):
 233                                                 continue
 234
 235                                 self.ZCacheable_invalidate()
 236                                 self.ZCacheable_set(None)
 237                                 self.http__refreshEtag()
 238
 239         else :
 240                 def setXMP(self, xmp):
 241                         """setXMP with XMP object
 242                         """
 243                         if self.size :
 244                                 bf = self.open('r+')
 245                                 x = XMP(bf, content_type=self.content_type)
 246                                 x.setXMP(xmp)
 247                                 x.save()
 248                                 self.updateSize(size=bf.tell())
 249
 250                                 # don't call update_data
 251                                 self.ZCacheable_invalidate()
 252                                 self.ZCacheable_set(None)
 253                                 self.http__refreshEtag()
 254
 255                                 # purge caches
 256                                 try : del self._methodResultsCache['getXMP']
 257                                 except KeyError : pass
 258                                 for name in ('getXmpPathIndex', ) :
 259                                         try :
 260                                                 del self._v__methodResultsCache[name]
 261                                         except (AttributeError, KeyError):
 262                                                 continue
 263
 264
 265
 266         security.declarePrivate('setXmpField')
 267         def setXmpFields(self, **kw):
 268                 xmp = self.getXMP()
 269                 if xmp :
 270                         doc = parseDoc(xmp)
 271                 else :
 272                         doc = xmputils.createEmptyXmpDoc()
 273
 274                 index = xmputils.getPathIndex(doc)
 275
 276                 pathPrefix = 'rdf:RDF/rdf:Description'
 277                 preferedNsDeclaration = 'rdf:RDF/rdf:Description'
 278
 279                 for id, value in kw.items() :
 280                         name = id.replace('_', ':')
 281                         info = xmpAccessors.get(name)
 282                         if not info : continue
 283                         root = info['root']
 284                         rdfType = info['rdfType']
 285                         path = '/'.join([p for p in [pathPrefix, root, name] if p])
 286
 287                         Metadata._setXmpField(index
 288                                                                 , path
 289                                                                 , rdfType
 290                                                                 , name
 291                                                                 , value
 292                                                                 , preferedNsDeclaration)
 293
 294                 # clean empty tags without attributes
 295                 context = doc.xpathNewContext()
 296                 nodeset = context.xpathEval(XPATH_EMPTY_TAGS)
 297                 while nodeset :
 298                         for n in nodeset :
 299                                 n.unlinkNode()
 300                                 n.freeNode()
 301                         nodeset = context.xpathEval(XPATH_EMPTY_TAGS)
 302
 303
 304
 305                 xmp = doc.serialize('utf-8')
 306                 # remove <?xml version="1.0" encoding="utf-8"?> header
 307                 xmp = xmp.split('?>', 1)[1].lstrip('\n')
 308                 self.setXMP(xmp)
 309
 310         @staticmethod
 311         def _setXmpField(index, path, rdfType, name, value, preferedNsDeclaration) :
 312                 if rdfType in ('Bag', 'Seq') :
 313                         value = value.replace(';', ',')
 314                         value = value.split(',')
 315                         value = [item.strip() for item in value]
 316                         value = filter(None, value)
 317
 318                 if value :
 319                         # edit
 320                         xmpPropIndex = index.getOrCreate(path
 321                                                                         , rdfType
 322                                                                         , preferedNsDeclaration)
 323                         if rdfType == 'prop' :
 324                                 xmpPropIndex.element.setContent(value)
 325                         else :
 326                                 #rdfPrefix = index.getDocumentNs()['http://www.w3.org/1999/02/22-rdf-syntax-ns#']
 327                                 func = getattr(xmputils, 'createRDF%s' % rdfType)
 328                                 newNode = func(name, value, index)
 329                                 oldNode = xmpPropIndex.element
 330                                 oldNode.replaceNode(newNode)
 331                 else :
 332                         # delete
 333                         xmpPropIndex = index.get(path)
 334                         if xmpPropIndex is not None :
 335                                 xmpPropIndex.element.unlinkNode()
 336                                 xmpPropIndex.element.freeNode()
 337
 338
 339 InitializeClass(Metadata)