Add optional_settings param to Ephemerides

It permits to easily extend the Ephemerides behaviour being able to pass some non-hardcoded settings.

The idea is to be able to pass a key-value based dictionary to inject some additional payload to the Ephemerides request.

This will simplify the process to change optional settings without the need to touch any line of code :)

It will also work for any table setting, or some other setting that needs to define/change the `request_payload`

More info about possible settings at https://ssd.jpl.nasa.gov/horizons.cgi?s_tset=1

Fix #1801

Author: XaviTorello

astroquery/jplhorizons/core.py

@@ -182,6 +182,7 @@ def ephemerides_async(self, airmass_lessthan=99,
                           refsystem='ICRF',
                           closest_apparition=False, no_fragments=False,
                           quantities=conf.eph_quantities,
+                          optional_settings=None,
                           get_query_payload=False,
                           get_raw_response=False, cache=True,
                           extra_precision=False):
@@ -487,6 +488,11 @@ def ephemerides_async(self, airmass_lessthan=99,
             <https://ssd.jpl.nasa.gov/?horizons_doc#table_quantities>`_;
             default: all quantities
 
+        optional_settings: dict, optional
+            key-value based dictionary to inject some additional optional settings
+            See `Optional observer-table settings" <https://ssd.jpl.nasa.gov/horizons.cgi?s_tset=1>`_;
+            default: empty optional setting
+
         get_query_payload : boolean, optional
             When set to `True` the method returns the HTTP request parameters as
             a dict, default: False
@@ -620,6 +626,14 @@ def ephemerides_async(self, airmass_lessthan=99,
         else:
             request_payload['SKIP_DAYLT'] = 'NO'
 
+        # inject optional settings if provided
+        if optional_settings:
+            assert isinstance(
+                optional_settings, dict
+            ), "optional_settings should be a dict"
+            for key, value in optional_settings.items():
+                request_payload[key] = value
+
         self.query_type = 'ephemerides'
 
         # return request_payload if desired

astroquery/jplhorizons/tests/test_jplhorizons.py

@@ -187,6 +187,52 @@ def test_ephemerides_query_payload():
         ('SKIP_DAYLT', 'YES')])
 
 
+def test_ephemerides_query_payload_with_optional_settings():
+    """
+    Assert that all optional settings are provided at query payload
+    """
+    obj = jplhorizons.Horizons(id='Halley', id_type='comet_name',
+                               location='290',
+                               epochs={'start': '2080-01-01',
+                                       'stop': '2080-02-01',
+                                       'step': '3h'})
+
+    optional_settings = {
+        "R_T_S_ONLY": "TVH",
+        "TIME_DIGITS": "SECONDS",
+    }
+    res = obj.ephemerides(airmass_lessthan=1.2, skip_daylight=True,
+                          closest_apparition=True,
+                          max_hour_angle=10,
+                          solar_elongation=(150, 180),
+                          get_query_payload=True,
+                          optional_settings=optional_settings)
+
+    assert res == OrderedDict([
+        ('batch', 1),
+        ('TABLE_TYPE', 'OBSERVER'),
+        ('QUANTITIES', "'1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,"
+                       "18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,"
+                       "33,34,35,36,37,38,39,40,41,42,43'"),
+        ('COMMAND', '"COMNAM=Halley; CAP;"'),
+        ('SOLAR_ELONG', '"150,180"'),
+        ('LHA_CUTOFF', '10'),
+        ('CSV_FORMAT', 'YES'),
+        ('CAL_FORMAT', 'BOTH'),
+        ('ANG_FORMAT', 'DEG'),
+        ('APPARENT', 'AIRLESS'),
+        ('REF_SYSTEM', 'J2000'),
+        ('EXTRA_PREC', 'NO'),
+        ('CENTER', "'290'"),
+        ('START_TIME', '"2080-01-01"'),
+        ('STOP_TIME', '"2080-02-01"'),
+        ('STEP_SIZE', '"3h"'),
+        ('AIRMASS', '1.2'),
+        ('SKIP_DAYLT', 'YES')
+        ] + list(optional_settings.items()),
+        )
+
+
 def test_elements_query_payload():
     res = (jplhorizons.Horizons(id='Ceres', location='500@10',
                                 epochs=2451544.5).elements(

docs/jplhorizons/jplhorizons.rst

@@ -189,7 +189,9 @@ limits fragment matching (73P-B would only match 73P-B), respectively.  Note
 that these options should only be used for comets and will crash the query for
 other object types. Extra precision in the queried properties can be requested
 using the ``extra_precision`` option.  Furthermore, ``get_query_payload=True``
-skips the query and only returns the query payload.
+skips the query and only returns the query payload. To pass additional settings
+to the request use the ``optional_settings`` passing a key-value
+dictionary.
 
 :meth:`~astroquery.jplhorizons.HorizonsClass.ephemerides` queries by default all
 available quantities from the JPL Horizons servers. This might take a while. If