FEAT: Add filecache to `web.get_omni_data()`

This will speed up the `get_omni_data()` function even more by keeping
a local cache of the omni data.

.gitignore

@@ -105,3 +105,11 @@ venv.bak/
 
 # misc
 tags
+
+# cache from filecache
+*.cache
+
+# pytest created files
+*.fts
+*.fts.gz
+IMF.dat

requirements.txt

 python-dateutil
 numpy
+filecache

swmfpy/web.py

@@ -19,6 +19,7 @@ import urllib
 import urllib.request
 import warnings
 from dateutil import rrule
+from filecache import filecache
 import numpy as np
 from .tools import _nearest, carrington_rotation_number
 
@@ -170,6 +171,11 @@ def get_omni_data(time_from, time_to, **kwargs):
                                         time_to=storm_end,
                                         resolution='low')
         ```
+
+    Note:
+        This function creates a filecache of omni data to speed up multiple
+        uses of it. The cache is in the directory you run the python
+        interpreter in.
     """
     # Author: Qusai Al Shidi
     # Email: qusai@umich.edu
@@ -208,7 +214,7 @@ def get_omni_data(time_from, time_to, **kwargs):
     for url in omni['urls'](time_from, time_to):
 
         # Parse omni data
-        for line in list(urllib.request.urlopen(url)):
+        for line in _download_omni_data(url):
             cols = line.decode('ascii').split()
 
             time = omni['parsetime'](cols)
@@ -228,6 +234,13 @@ def get_omni_data(time_from, time_to, **kwargs):
     return return_data
 
 
+@filecache
+def _download_omni_data(url):
+    """Downloads omni data and returns as list
+    """
+    return list(urllib.request.urlopen(url))
+
+
 def _urls_omni_hires(time_from, time_to):
     """Returns hires omni urls from time_from to time_to
     """
@@ -484,7 +497,7 @@ def download_magnetogram_adapt(time, map_type='fixed', **kwargs):
 
     for filename in filenames:
         # Only try to download if the file does not exist
-        if os.path.isfile(directory+filename) == True:
+        if os.path.isfile(directory+filename):
             warnings.warn(f'{filename} exists, not downloading',
                           RuntimeWarning)
         else:

tests/test_web.py

@@ -6,8 +6,13 @@ import datetime as dt
 from swmfpy.web import *
 
 TIME = dt.datetime(2016, 2, 3, 2, 1, 1)
-
+TIMES = (dt.datetime(2016, 1, 2, 3), dt.datetime(2016, 3, 2, 1))
 
 def test_download_magnetogram_adapt():
     download_magnetogram_adapt(TIME)
     assert isfile('adapt40311_03k012_201602030200_i00015600n1.fts')
+
+def test_get_omni_data():
+    data = get_omni_data(*TIMES)
+    assert isinstance(data, dict), 'Incorrect type for omni data'
+    assert data['times'][0] == TIMES[0], 'Starting time is incorrect'