review uses of strftime to use a common central date format sfatime.SFATIME_FORMAT

[sfa.git] / sfa / util / sfatime.py

diff --git a/sfa/util/sfatime.py b/sfa/util/sfatime.py
index 901b4e0..d14f44b 100644 (file)
--- a/sfa/util/sfatime.py
+++ b/sfa/util/sfatime.py
@@ -1,10 +1,73 @@
+#----------------------------------------------------------------------
+# Copyright (c) 2008 Board of Trustees, Princeton University
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and/or hardware specification (the "Work") to
+# deal in the Work without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Work, and to permit persons to whom the Work
+# is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Work.
+#
+# THE WORK IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE WORK OR THE USE OR OTHER DEALINGS
+# IN THE WORK.
+#----------------------------------------------------------------------
+from types import StringTypes
 import dateutil.parser
+import datetime
+import time
 
-def utcparse(str):
+from sfa.util.sfalogging import logger
+
+SFATIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
+
+def utcparse(input):
     """ Translate a string into a time using dateutil.parser.parse but make sure it's in UTC time and strip
-    the timezone, so that it's compatible with normal datetime.datetime objects"""
-    
-    t = dateutil.parser.parse(str)
-    if not t.utcoffset() is None:
-        t = t.utcoffset() + t.replace(tzinfo=None)
-    return t
+the timezone, so that it's compatible with normal datetime.datetime objects.
+
+For safety this can also handle inputs that are either timestamps, or datetimes
+"""
+    # prepare the input for the checks below by
+    # casting strings ('1327098335') to ints
+    if isinstance(input, StringTypes):
+        try:
+            input = int(input)
+        except ValueError:
+            pass
+
+    if isinstance (input, datetime.datetime):
+        logger.warn ("argument to utcparse already a datetime - doing nothing")
+        return input
+    elif isinstance (input, StringTypes):
+        t = dateutil.parser.parse(input)
+        if t.utcoffset() is not None:
+            t = t.utcoffset() + t.replace(tzinfo=None)
+        return t
+    elif isinstance (input, (int,float,long)):
+        return datetime.datetime.fromtimestamp(input)
+    else:
+        logger.error("Unexpected type in utcparse [%s]"%type(input))
+
+def datetime_to_string(input):
+    return datetime.datetime.strftime(input, SFATIME_FORMAT)
+
+def datetime_to_utc(input):
+    return time.gmtime(datetime_to_epoch(input))
+
+def datetime_to_epoch(input):
+    return int(time.mktime(input.timetuple()))
+
+def adjust_datetime(input, days=0, hours=0, minutes=0, seconds=0):
+    """
+    Adjust the input date by the specified delta (in seconds).
+    """
+    dt = utcparse(input)
+    return dt + datetime.timedelta(days=days, hours=hours, minutes=minutes, seconds=seconds)