use pyPdf instead of pdftk to extract non standard metadata from pdf

product/ERP5/Document/PDFDocument.py

@@ -266,28 +266,19 @@ class PDFDocument(Image):
         value = ':'.join(item_list[1:]).strip()
         result[key] = value
 
-      # Then we use pdftk to get extra metadata
+      # Then we use pyPdf to get extra metadata
       try:
-        command = ['pdftk', tmp.name, 'dump_data', 'output']
-        command_result = Popen(command, stdout=PIPE).communicate()[0]
-      except OSError, e:
-        # if pdftk not found, pass
-        if e.errno != errno.ENOENT:
-          raise
+        from pyPdf import PdfFileReader
+      except ImportError:
+        # if pyPdf not found, pass
+        pass
       else:
-        line_list = (line for line in command_result.splitlines())
-        while True:
-          try:
-            line = line_list.next()
-          except StopIteration:
-            break
-          if line.startswith('InfoKey'):
-            key = line[len('InfoKey: '):]
-            line = line_list.next()
-            assert line.startswith('InfoValue: '),\
-                "Wrong format returned by pdftk dump_data"
-            value = line[len('InfoValue: '):]
-            result.setdefault(key, value)
+        pdf_file = PdfFileReader(tmp)
+        for info_key, info_value in pdf_file.getDocumentInfo().iteritems():
+          info_key = info_key.lstrip("/")
+          if isinstance(info_value, unicode):
+            info_value = info_value.encode("utf-8")
+          result.setdefault(info_key, info_value)
     finally:
       tmp.close()