diff --git a/metawarc/cmds/indexer.py b/metawarc/cmds/indexer.py
index ab2bcaf..9c61272 100644
--- a/metawarc/cmds/indexer.py
+++ b/metawarc/cmds/indexer.py
@@ -17,7 +17,7 @@
 
 def bufcount(filename):
     """Count number of lines"""
-    f = open(filename)                  
+    f = open(filename)
     lines = 0
     buf_size = 1024 * 1024
     read_f = f.read # loop optimization
@@ -26,7 +26,7 @@ def bufcount(filename):
     while buf:
         lines += buf.count('\n')
         buf = read_f(buf_size)
-    f.close() 
+    f.close()
     return lines
 
 def cdx_size_counter(filename):
@@ -57,33 +57,35 @@ def index_content(self, fromfile):
             print('CDX file found. Estimated number of WARC records %d' % (records_num))
         else:
             print("No CDX file. Cant measure progress")
-        n = 0 
-        for record in iterator:
-            if record.rec_type != "response":
-                continue
-            n += 1      
-            if records_num is not None:
-                if n % THRESHOLD == 0: print('Processed %d (%0.2f%%) records' % (n, n*100.0 / records_num))            
-            else:
-                if n % THRESHOLD == 0: print('Processed %d records' % (n))
-            if record.http_headers is not None:
-                dbrec = models.Record()
-                dbrec.warc_id = record.rec_headers.get_header("WARC-Record-ID").rsplit(':', 1)[-1].strip('>')
-                content_type = record.http_headers.get_header("content-type")                
-                dbrec.content_type = content_type
-                dbrec.offset = iterator.get_record_offset()
-                dbrec.length = iterator.get_record_length()
-                dbrec.url = record.rec_headers.get_header("WARC-Target-URI")
-                warc_date  = record.rec_headers.get_header("WARC-Date")
-                dbrec.rec_date = datetime.strptime(warc_date, "%Y-%m-%dT%H:%M:%S%z")
-                dbrec.content_length = int(record.rec_headers.get_header("Content-Length"))
-                dbrec.status_code = int(record.http_headers.get_statuscode())
-                dbrec.headers = json.dumps(dict(record.http_headers.headers))
-                dbrec.source = fromfile
-                dbrec.filename = dbrec.url.rsplit("?", 1)[0].rsplit("/", 1)[-1].lower() 
-                dbrec.ext = dbrec.filename.rsplit(".", 1)[-1] if dbrec.filename.find(".") > -1 else ""
-                session.add(dbrec)
-                session.commit()
+        n = 0
+        try:
+            for record in iterator:
+                if record.rec_type != "response":
+                    continue
+                n += 1
+                if records_num is not None:
+                    if n % THRESHOLD == 0: print('Processed %d (%0.2f%%) records' % (n, n*100.0 / records_num))
+                else:
+                    if n % THRESHOLD == 0: print('Processed %d records' % (n))
+                if record.http_headers is not None:
+                    dbrec = models.Record()
+                    dbrec.warc_id = record.rec_headers.get_header("WARC-Record-ID").rsplit(':', 1)[-1].strip('>')
+                    content_type = record.http_headers.get_header("content-type")
+                    dbrec.content_type = content_type
+                    dbrec.offset = iterator.get_record_offset()
+                    dbrec.length = iterator.get_record_length()
+                    dbrec.url = record.rec_headers.get_header("WARC-Target-URI")
+                    warc_date  = record.rec_headers.get_header("WARC-Date")
+                    dbrec.rec_date = datetime.strptime(warc_date, "%Y-%m-%dT%H:%M:%S%z")
+                    dbrec.content_length = int(record.rec_headers.get_header("Content-Length"))
+                    dbrec.status_code = int(record.http_headers.get_statuscode())
+                    dbrec.headers = json.dumps(dict(record.http_headers.headers))
+                    dbrec.source = fromfile
+                    dbrec.filename = dbrec.url.rsplit("?", 1)[0].rsplit("/", 1)[-1].lower()
+                    dbrec.ext = dbrec.filename.rsplit(".", 1)[-1] if dbrec.filename.find(".") > -1 else ""
+                    session.add(dbrec)
+        finally:
+            session.commit()
         resp.close()
 
     def calc_stats(self, mode='mime'):
@@ -95,14 +97,14 @@ def calc_stats(self, mode='mime'):
         engine = create_engine("sqlite:///metawarc.db", echo=False)
         session = Session(engine)
         if mode == 'mimes':
-             results = session.query(models.Record.content_type, func.sum(models.Record.content_length), func.count(models.Record.warc_id)).group_by(models.Record.content_type).all()        
+             results = session.query(models.Record.content_type, func.sum(models.Record.content_length), func.count(models.Record.warc_id)).group_by(models.Record.content_type).all()
              title = 'Group by mime type'
              headers = ('mime', 'size', 'size share', 'count')
         elif mode == 'exts':
-             results = session.query(models.Record.ext, func.sum(models.Record.content_length), func.count(models.Record.warc_id)).group_by(models.Record.ext).all()        
+             results = session.query(models.Record.ext, func.sum(models.Record.content_length), func.count(models.Record.warc_id)).group_by(models.Record.ext).all()
              title = 'Group by file extension'
              headers = ('extension', 'size', 'size share', 'count')
-  
+
         reptable = Table(title=title)
         reptable.add_column(headers[0], justify="left", style="magenta")
         for key in headers[1:-1]: