Merge pull request #88 from mwcraig/better-metadata

Change metadata to case-insensitive OrderedDict

ccdproc/ccddata.py

@@ -13,6 +13,8 @@
 from astropy import units as u
 import astropy
 
+from .utils.collections import CaseInsensitiveOrderedDict
+
 adu = u.adu
 electron = u.def_unit('electron')
 photon = u.photon
@@ -118,19 +120,16 @@ def meta(self):
     @meta.setter
     def meta(self, value):
         if value is None:
-            self._meta = fits.Header()
-        elif isinstance(value, fits.Header):
-            self._meta = value
+            self._meta = CaseInsensitiveOrderedDict()
         else:
-            h = fits.Header()
+            h = CaseInsensitiveOrderedDict()
             try:
                 for k, v in value.items():
                     h[k] = v
             except (ValueError, AttributeError):
                 raise TypeError('NDData meta attribute must be dict-like')
             self._meta = h
 
-
     @property
     def uncertainty(self):
         return self._uncertainty
@@ -148,7 +147,7 @@ def uncertainty(self, value):
             self._uncertainty = value
 
     def to_hdu(self):
-        """Creates an HDUList object from a CCDData object
+        """Creates an HDUList object from a CCDData object.
 
            Raises
            -------
@@ -160,13 +159,16 @@ def to_hdu(self):
            hdulist : astropy.io.fits.HDUList object
 
         """
-        hdu = fits.PrimaryHDU(self.data, self.header)
+        header = fits.Header()
+        for k, v in self.header.items():
+            header[k] = v
+        hdu = fits.PrimaryHDU(self.data, header)
         hdulist = fits.HDUList([hdu])
         return hdulist
 
     def copy(self):
         """
-        Return a copy of the CCDData object
+        Return a copy of the CCDData object.
         """
         return copy.deepcopy(self)
 
@@ -288,7 +290,7 @@ def fits_ccddata_writer(ccd_data, filename, **kwd):
     kwd :
         All additional keywords are passed to :py:mod:`astropy.io.fits`
     """
-    hdu = fits.PrimaryHDU(data=ccd_data.data, header=ccd_data.header)
+    hdu = ccd_data.to_hdu()
     hdu.writeto(filename, **kwd)
 
 

ccdproc/tests/test_ccddata.py

@@ -39,7 +39,8 @@ def test_initialize_from_FITS(ccd_data, tmpdir):
     assert cd.shape == (10, 10)
     assert cd.size == 100
     assert np.issubdtype(cd.data.dtype, np.float)
-    assert cd.meta == hdu.header
+    for k, v in hdu.header.items():
+        assert cd.meta[k] == v
 
 
 def test_initialize_from_FITS_bad_keyword_raises_error(ccd_data, tmpdir):
@@ -63,9 +64,16 @@ def test_ccddata_writer(ccd_data, tmpdir):
     np.testing.assert_array_equal(ccd_data.data, ccd_disk.data)
 
 
-def test_ccddata_meta_is_fits_header(ccd_data):
+def test_ccddata_meta_is_case_insensitive(ccd_data):
+    key = 'SoMeKEY'
+    ccd_data.meta[key] = 10
+    assert key.lower() in ccd_data.meta
+    assert key.upper() in ccd_data.meta
+
+
+def test_ccddata_meta_is_not_fits_header(ccd_data):
     ccd_data.meta = {'OBSERVER': 'Edwin Hubble'}
-    assert isinstance(ccd_data.meta, fits.Header)
+    assert not isinstance(ccd_data.meta, fits.Header)
 
 
 def test_fromMEF(ccd_data, tmpdir):

ccdproc/tests/test_ccdproc_logging.py

@@ -18,7 +18,7 @@ def test_log_string(ccd_data, key):
     assert add_key not in ccd_data.meta
     # Long keyword names should be accessible with just the keyword name
     # without HIERARCH -- is it?
-    assert new.meta[add_key] == ''
+    assert new.meta[add_key] is None
 
 
 def test_log_keyword(ccd_data):

ccdproc/utils/collections.py

@@ -0,0 +1,35 @@
+"""
+Useful objects based on collections
+"""
+
+from __future__ import (absolute_import, print_function)
+
+from astropy.utils.compat.odict import OrderedDict
+
+
+class CaseInsensitiveOrderedDict(OrderedDict):
+    """
+    docstring for CaseInsensitiveOrderedDict
+    """
+
+    def __init__(self, *arg, **kwd):
+        super(CaseInsensitiveOrderedDict, self).__init__(*arg, **kwd)
+
+    def _transform_key(self, key):
+        return key.upper()
+
+    def __setitem__(self, key, value):
+        super(CaseInsensitiveOrderedDict,
+              self).__setitem__(self._transform_key(key), value)
+
+    def __getitem__(self, key):
+        return super(CaseInsensitiveOrderedDict,
+                     self).__getitem__(self._transform_key(key))
+
+    def __delitem__(self, key):
+        return super(CaseInsensitiveOrderedDict,
+                     self).__delitem__(self._transform_key(key))
+
+    def __contains__(self, key):
+        return super(CaseInsensitiveOrderedDict,
+                     self).__contains__(self._transform_key(key))