Merge pull request #57 in TPSH/ckanext-odsh from test-hash to master

* commit '0dda2def':
  resets file pointer to 0
  adds debug messages to _raise_validation_error_if_hash_values_differ

ckanext/odsh/lib/uploader.py

@@ -29,6 +29,7 @@ def _raise_validation_error_if_virus_found(filename, upload_file):
 
 
 def calculate_hash(upload_file):
+    upload_file.seek(0)
     hash_md5 = hashlib.md5()
     for chunk in iter(lambda: upload_file.read(4096), b""):
             hash_md5.update(chunk)
@@ -41,6 +42,8 @@ def _raise_validation_error_if_hash_values_differ(upload_file, resource):
     if hash_from_resource:
         hash_from_calculation = calculate_hash(upload_file)
         if not hash_from_calculation == hash_from_resource:
+            log.debug('hash from calculation: {}'.format(hash_from_calculation))
+            log.debug('hash from resource: {}'.format(hash_from_resource))
             raise logic.ValidationError({'upload': ['Berechneter Hash und mitgelieferter Hash sind unterschiedlich']})