add save fn, add test #1578

Author: oesteban

nipype/interfaces/base.py

@@ -1149,13 +1149,23 @@ def version(self):
         return self._version
 
     def load_inputs_from_json(self, json_file):
+        """
+        A convenient way to load pre-set inputs from a JSON file.
+        """
+
         with open(json_file) as fhandle:
             inputs_dict = json.load(fhandle)
 
         for key, val in list(inputs_dict.items()):
             if not isdefined(getattr(self.inputs, key, Undefined)):
                 setattr(self.inputs, key, val)
 
+    def save_inputs_to_json(self, json_file):
+        """
+        A convenient way to save current inputs to a JSON file.
+        """
+        with open(json_file, 'w') as fhandle:
+            json.dump(self.inputs.get(), fhandle, indent=4)
 
 
 class Stream(object):

nipype/interfaces/tests/test_base.py

@@ -455,6 +455,31 @@ def _run_interface(self, runtime):
     nib.BaseInterface.input_spec = None
     yield assert_raises, Exception, nib.BaseInterface
 
+def test_BaseInterface_load_save_inputs():
+    tmp_dir = tempfile.mkdtemp()
+    tmp_json = os.path.join(tmp_dir, 'settings.json')
+
+
+    class InputSpec(nib.TraitedSpec):
+        input1 = nib.traits.Int()
+        input2 = nib.traits.Float()
+        input3 = nib.traits.Bool()
+        input4 = nib.traits.Str()
+
+    class DerivedInterface(nib.BaseInterface):
+        input_spec = InputSpec
+
+        def __init__(self, **inputs):
+            super(DerivedInterface, self).__init__(**inputs)
+
+    inputs_dict = {'input1': 12, 'input2': 3.4, 'input3': True,
+                   'input4': 'some string'}
+    bif = DerivedInterface(**inputs_dict)
+    bif.save_inputs_to_json(tmp_json)
+    bif2 = DerivedInterface()
+    bif2.load_inputs_from_json(tmp_json)
+    yield assert_equal, inputs_dict, bif2.inputs.get()
+
 
 def assert_not_raises(fn, *args, **kwargs):
     fn(*args, **kwargs)