do not depend on types.StringTypes anymore

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

diff --git a/sfa/util/sfatime.py b/sfa/util/sfatime.py
index 34f4dce..7435667 100644 (file)
--- a/sfa/util/sfatime.py
+++ b/sfa/util/sfatime.py
@@ -1,11 +1,37 @@
-from types import StringTypes
-import dateutil.parser
-import datetime
+#----------------------------------------------------------------------
+# 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 __future__ import print_function
+
 import time
+import datetime
+import dateutil.parser
+import calendar
+import re
 
 from sfa.util.sfalogging import logger
+from sfa.util.py23 import StringType
 
-DATEFORMAT = "%Y-%m-%dT%H:%M:%SZ"
+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
@@ -13,18 +39,38 @@ 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
 """
-    # perpare the input for the checks below by
+
+    def handle_shorthands (input):
+        """recognize string like +5d or +3w or +2m as 
+        2 days, 3 weeks or 2 months from now"""
+        if input.startswith('+'):
+            match=re.match (r"([0-9]+)([dwm])",input[1:])
+            if match:
+                how_many=int(match.group(1))
+                what=match.group(2)
+                if what == 'd':         d=datetime.timedelta(days=how_many)
+                elif what == 'w':       d=datetime.timedelta(weeks=how_many)
+                elif what == 'm':       d=datetime.timedelta(weeks=4*how_many)
+                return datetime.datetime.utcnow()+d
+
+    # prepare the input for the checks below by
     # casting strings ('1327098335') to ints
-    if isinstance(input, StringTypes):
+    if isinstance(input, StringType):
         try:
             input = int(input)
         except ValueError:
-            pass
-          
+            try:
+                new_input=handle_shorthands(input)
+                if new_input is not None: input=new_input
+            except:
+                import traceback
+                traceback.print_exc()
+
+    #################### here we go
     if isinstance (input, datetime.datetime):
-        logger.warn ("argument to utcparse already a datetime - doing nothing")
+        #logger.info ("argument to utcparse already a datetime - doing nothing")
         return input
-    elif isinstance (input, StringTypes):
+    elif isinstance (input, StringType):
         t = dateutil.parser.parse(input)
         if t.utcoffset() is not None:
             t = t.utcoffset() + t.replace(tzinfo=None)
@@ -34,14 +80,38 @@ For safety this can also handle inputs that are either timestamps, or datetimes
     else:
         logger.error("Unexpected type in utcparse [%s]"%type(input))
 
-def datetime_to_string(input):
-    return datetime.datetime.strftime(input, DATEFORMAT)
-
-def datetime_to_utc(input):
-    return time.gmtime(datetime_to_epoch(input))    
+def datetime_to_string(dt):
+    return datetime.datetime.strftime(dt, SFATIME_FORMAT)
 
-def datetime_to_epoch(input):
-    return int(time.mktime(input.timetuple()))
+def datetime_to_utc(dt):
+    return time.gmtime(datetime_to_epoch(dt))
 
+# see https://docs.python.org/2/library/time.html 
+# all timestamps are in UTC so time.mktime() would be *wrong*
+def datetime_to_epoch(dt):
+    return int(calendar.timegm(dt.timetuple()))
 
+def add_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)
 
+if __name__ == '__main__':
+        # checking consistency
+    print(20*'X')
+    print(("Should be close to zero: %s"%(datetime_to_epoch(datetime.datetime.utcnow())-time.time())))
+    print(20*'X')
+    for input in [
+            '+2d',
+            '+3w',
+            '+2m',
+            1401282977.575632,
+            1401282977,
+            '1401282977',
+            '2014-05-28',
+            '2014-05-28T15:18',
+            '2014-05-28T15:18:30',
+    ]:
+        print("input=%20s -> parsed %s"%(input,datetime_to_string(utcparse(input))))