@@ 415,6 415,28 @@ def nary_pack(*bytestr):
     )
 
 
+def convert_io(spec, args):
+    """Tries to convert string values into the well typed input values
+    needed for prepare or schedule calls.
+
+    May be usefull for user interfaces (or coming from json values).
+
+    """
+    if args is None and not len(spec):
+        return
+
+    typed = {}
+    for field in spec:
+        inp = _iobase.from_type(
+            field['type'], field['name'], field['required'], field['choices']
+        )
+        val = inp.from_string(args)
+        if val is not None:
+            typed[inp.name] = val
+
+    return typed
+
+
 def pack_io(spec, args):
     if args is None and not len(spec):
         return

          

@@ 48,6 48,9 @@ class _iobase:
 
 class number(_iobase):
 
+    def from_string(self, args):
+        return self.binary_decode(args)
+
     def binary_encode(self, args):
         val = self.val(args)
         if val is not None:

          
@@ 69,6 72,9 @@ class number(_iobase):
 
 class string(_iobase):
 
+    def from_string(self, args):
+        return self.val(args)
+
     def binary_encode(self, args):
         val = self.val(args)
         if val is not None:

          
@@ 86,6 92,13 @@ class string(_iobase):
 
 class file(_iobase):
 
+    def from_string(self, args):
+        val = self.val(args)
+        if val is not None:
+            if not isinstance(val, bytes):
+                return val.encode('utf-8')
+            return val
+
     def binary_encode(self, args):
         val = self.val(args)
         if val is not None:

          
@@ 101,6 114,11 @@ class file(_iobase):
 
 class datetime(_iobase):
 
+    def from_string(self, args):
+        val = self.val(args)
+        if val is not None:
+            return defaultparse(val)
+
     def binary_encode(self, args):
         val = self.val(args)
         if val is None:

          
@@ 156,6 174,12 @@ def _parsedatetime(strdt):
 
 class moment(_iobase):
 
+    def from_string(self, args):
+        val = self.val(args)
+        if val is not None:
+            lisp.evaluate(val, env=_MOMENT_ENV)
+            return val
+
     def binary_encode(self, args):
         val = self.val(args)
         if val is None:

          

@@ 2,6 2,7 @@ import pytest
 from datetime import datetime as dt
 
 from rework.helper import (
+    convert_io,
     filterio,
     iospec,
     host,

          
@@ 234,6 235,29 @@ def test_moment_input(engine, cleanup):
     assert when == dt(2021, 1, 1, 9, 0)
 
 
+def test_convert_io(engine, cleanup):
+    reset_ops(engine)
+    register_tasks()
+    api.freeze_operations(engine)
+    args = {
+        'myfile.txt': 'some file',
+        'name': 'Babar',
+        'weight': '65',
+        'birthdate': '1973-5-20T09:00:00',
+        'option': 'foo'
+    }
+    specs = iospec(engine)
+    spec = filterio(specs, 'yummy')
+    typed = convert_io(spec, args)
+    assert typed == {
+        'myfile.txt': b'some file',
+        'weight': 65,
+        'birthdate': dt(1973, 5, 20, 9, 0),
+        'name': 'Babar',
+        'option': 'foo'
+    }
+
+
 def test_prepare_with_inputs(engine, cleanup):
     reset_ops(engine)
     register_tasks()