Moved staging file preview creation logic from documents.views to staging.py

apps/documents/staging.py

@@ -7,6 +7,10 @@ from django.core.exceptions import ObjectDoesNotExist
 from django.utils.translation import ugettext
 
 from documents.conf.settings import STAGING_DIRECTORY
+from documents.conf.settings import DEFAULT_TRANSFORMATIONS
+from documents.conf.settings import STAGING_FILES_PREVIEW_SIZE
+from converter import TRANFORMATION_CHOICES
+from converter.api import convert#, in_image_cache, QUALITY_DEFAULT
 
 HASH_FUNCTION = lambda x: hashlib.sha256(x).hexdigest()
 #TODO: Do benchmarks
@@ -74,3 +78,19 @@ class StagingFile(object):
                 pass
             else:
                 raise OSError(ugettext(u'Unable to delete staging file: %s') % exc)
+
+    def preview(self):
+        transformation_list = []
+        errors = []
+        for transformation in DEFAULT_TRANSFORMATIONS:
+            try:
+                if transformation['name'] in TRANFORMATION_CHOICES:
+                    output = TRANFORMATION_CHOICES[transformation['name']] % eval(transformation['arguments'])
+                    transformation_list.append(output)
+            except Exception, e:
+                errors.append(e)
+
+        tranformation_string = ' '.join(transformation_list)
+
+        output_file = convert(self.filepath, size=STAGING_FILES_PREVIEW_SIZE, extra_options=tranformation_string, cleanup_files=False)
+        return output_file, errors