Fix stream_extract/stream_intervals restart around timestamp == 0.

nilmdb/server/nilmdb.py

@@ -334,14 +334,14 @@ class NilmDB(object):
 
         Returns (intervals, restart) tuple.
 
-        intervals is a list of [start,end] timestamps of all intervals
+        'intervals' is a list of [start,end] timestamps of all intervals
         that exist for path, between start and end.
 
-        restart, if nonzero, means that there were too many results to
-        return in a single request.  The data is complete from the
-        starting timestamp to the point at which it was truncated,
-        and a new request with a start time of 'restart' will fetch
-        the next block of data.
+        'restart', if not None, means that there were too many results
+        to return in a single request.  The data is complete from the
+        starting timestamp to the point at which it was truncated, and
+        a new request with a start time of 'restart' will fetch the
+        next block of data.
         """
         stream_id = self._stream_id(path)
         intervals = self._get_intervals(stream_id)
@@ -363,7 +363,7 @@ class NilmDB(object):
                 break
             result.append([i.start, i.end])
         else:
-            restart = 0
+            restart = None
         return (result, restart)
 
     def stream_create(self, path, layout_name):
@@ -521,10 +521,10 @@ class NilmDB(object):
         """
         Returns (data, restart) tuple.
 
-        data is ASCII-formatted data from the database, formatted
+        'data' is ASCII-formatted data from the database, formatted
         according to the layout of the stream.
 
-        restart, if nonzero, means that there were too many results to
+        'restart', if not None, means that there were too many results to
         return in a single request.  The data is complete from the
         starting timestamp to the point at which it was truncated,
         and a new request with a start time of 'restart' will fetch
@@ -543,7 +543,7 @@ class NilmDB(object):
         result = []
         matched = 0
         remaining = self.max_results
-        restart = 0
+        restart = None
         for interval in intervals.intersection(requested):
             # Reading single rows from the table is too slow, so
             # we use two bisections to find both the starting and
@@ -568,7 +568,7 @@ class NilmDB(object):
             # Count them
             remaining -= row_end - row_start
 
-            if restart:
+            if restart is not None:
                 break
 
         if count:

nilmdb/server/server.py

@@ -386,7 +386,7 @@ class Stream(NilmApp):
                                                            diffpath)
                 response = ''.join([ json.dumps(i) + "\r\n" for i in ints ])
                 yield response
-                if restart == 0:
+                if restart is None:
                     break
                 start = restart
         return content(start, end)
@@ -432,7 +432,7 @@ class Stream(NilmApp):
                 (data, restart) = self.db.stream_extract(path, start, end)
                 yield data
 
-                if restart == 0:
+                if restart is None:
                     return
                 start = restart
         return content(start, end, count)