first functioning version of vamdc molecule queries with caching

enabled, plus some docs

astroquery/vamdc/core.py

@@ -44,10 +44,12 @@ def __init__(self):
 
         from vamdclib import nodes as vnodes
         from vamdclib import request as vrequest
+        from vamdclib import results as vresults
         from vamdclib import specmodel
 
         self._vnodes = vnodes
         self._vrequest = vrequest
+        self._vresults = vresults
 
         self._nl = vnodes.Nodelist()
         self._cdms = self._nl.findnode('cdms')
@@ -91,10 +93,9 @@ def query_molecule(self, molecule_name, chem_re_flags=0, cache=True):
         myhashpath = os.path.join(self.CACHE_LOCATION,
                                   myhash)
         if os.path.exists(myhashpath) and cache:
-            with open(myhashpath, 'r') as fh:
+            with open(myhashpath, 'rb') as fh:
                 xml = fh.read()
-            result = self._vrequest.Result()
-            result.Xml = xml
+            result = self._vresults.Result(xml=xml)
             result.populate_model()
         else:
             species_id_dict = self.species_lookuptable.find(molecule_name,
@@ -111,7 +112,7 @@ def query_molecule(self, molecule_name, chem_re_flags=0, cache=True):
             result = request.dorequest()
 
             if cache:
-                with open(myhashpath, 'w') as fh:
+                with open(myhashpath, 'wb') as fh:
                     xml = fh.write(result.Xml)
 
         return result

docs/vamdc/vamdc.rst

@@ -0,0 +1,42 @@
+.. doctest-skip-all
+
+.. _astroquery.vamdc:
+
+**********************************
+Vamdc Queries (`astroquery.vamdc`)
+**********************************
+
+Getting Started
+===============
+
+The astroquery vamdc interface requires vamdclib_.  The documentation is sparse
+to nonexistant, but installation is straightforward::
+
+    pip install https://github.com/keflavich/vamdclib/archive/master.zip
+
+This is the personal fork of the astroquery maintainer that includes astropy's
+setup helpers on top of the vamdclib infrastructure.
+
+Examples
+========
+
+If you want to compute the partition function, you can do so using a combination
+of astroquery and the vamdclib tools::
+
+.. code-block:: python
+
+    >>> from astroquery.vamdc import Vamdc
+    >>> ch3oh = Vamdc.query_molecule('CH3OH')
+    >>> from vamdclib import specmodel
+    >>> partition_func = specmodel.calculate_partitionfunction(ch3oh.data['States'],
+                                                               temperature=100)
+    >>> print(partition_func)
+    {'XCDMS-149': 1185.5304044622881}
+
+Reference/API
+=============
+
+.. automodapi:: astroquery.vamdc
+    :no-inheritance-diagram:
+
+.. _vamdclib: http://vamdclib.readthedocs.io/en/latest/