got rid of sort_by refactoring. converting params back to dict when use_json=True instead.

Author: jaymedina

astroquery/mast/services.py

@@ -281,27 +281,26 @@ def service_request_async(self, service, params, page_size=None, page=None, use_
         if page_size is not None:
             catalogs_request.append(('pagesize', page_size))
 
-        # Updating syntax of sort_by inputs if sort direction
-        # was specified
-        if 'sort_by' in params.keys():
-            new_sort_by = []
-
-            # If just a tuple is fed, turn it into a list with a single tuple element
-            if not isinstance(params['sort_by'], list):
-                params['sort_by'] = [(params['sort_by'][0], params['sort_by'][1])]
-            for item in params['sort_by']:
-                if item[0].lower() in ['asc', 'desc']:
-                    new_sort_by.append(item[1] + '.' + item[0])
-                params['sort_by'] = new_sort_by
-
         if not use_json:
             # Decompose filters, sort
             for prop, value in kwargs.items():
                 params[prop] = value
             catalogs_request.extend(self._build_catalogs_params(params))
         else:
             headers['Content-Type'] = 'application/json'
-            catalogs_request = params
+
+            # After parameter syntax is updated, revert back to dictionary
+            # so params can be passed as a JSON dictionary
+            params_dict = {}
+            catalogs_request.extend(self._build_catalogs_params(params))
+            for key, val in catalogs_request:
+                params_dict.setdefault(key, []).append(val)
+            catalogs_request = params_dict
+
+            # Removing single-element lists. Single values will live on their own.
+            for key in catalogs_request.keys():
+                if len(catalogs_request[key]) == 1:
+                    catalogs_request[key] = catalogs_request[key][0]
 
         response = self._request('POST', request_url, data=catalogs_request, headers=headers, use_json=use_json)
         return response
@@ -328,9 +327,21 @@ def _build_catalogs_params(self, params):
             elif prop == 'page_size':
                 catalog_params.extend(('pagesize', value))
             elif prop == 'sort_by':
-                # Loop through each value
-                for sort_item in value:
-                    catalog_params.append(('sort_by', sort_item))
+                # Loop through each value if list
+                if isinstance(value, list):
+                    for sort_item in value:
+                        # Determine if tuple with sort direction
+                        if isinstance(sort_item, tuple):
+                            catalog_params.append(('sort_by', sort_item[1] + '.' + sort_item[0]))
+                        else:
+                            catalog_params.append(('sort_by', sort_item))
+                else:
+                    # A single sort
+                    # Determine if tuple with sort direction
+                    if isinstance(value, tuple):
+                        catalog_params.append(('sort_by', value[0] + '.' + value[1]))
+                    else:
+                        catalog_params.append(('sort_by', value))
             elif prop == 'columns':
                 catalog_params.extend(tuple(('columns', col) for col in value))
             else: