Added to_dict method to Message (fixes #107) (#108)

* require ruamel

* added base module

* added from_dict and to_dict to Time

* bug fix: bad dep name

* added to_dict to Message

* added basic test_to_dict

setup.py

@@ -19,7 +19,8 @@
     license='mit',
     install_requires=[
         'attrs>=17.2.0',
-        'typing-extensions>=3.7.2'
+        'typing-extensions>=3.7.2',
+        'ruamel.yaml>=0.15.89'
     ],
     setup_requires=[
         'pytest-runner'

src/rozzy/definitions/__init__.py

@@ -1,7 +1,7 @@
+from .base import Time
 from .msg import Constant, ConstantValue, Field, MsgFormat
 from .srv import SrvFormat
 from .action import ActionFormat
 from .package import Package, PackageDatabase
-from .bag import Time
 from .format import FormatDatabase
 from .type_db import TypeDatabase, Message

src/rozzy/definitions/bag.py

@@ -1,4 +1,4 @@
-__all__ = ['BagReader']
+__all__ = ('BagReader',)
 
 from typing import (Dict, Sequence, Union, Optional, Tuple, List, Type,
                     Callable)
@@ -12,16 +12,12 @@
 
 import attr
 
+from .base import Time
+
 logger: logging.Logger = logging.getLogger(__name__)
 logger.setLevel(logging.DEBUG)
 
 
-@attr.s(frozen=True, slots=True)
-class Time:
-    secs: int = attr.ib()
-    nsecs: int = attr.ib()
-
-
 def decode_uint8(v: bytes) -> int:
     return struct.unpack('<B', v)[0]
 

src/rozzy/definitions/base.py

@@ -0,0 +1,19 @@
+__all__ = ('Time',)
+
+from typing import Dict, Any
+
+import attr
+
+
+@attr.s(frozen=True, slots=True)
+class Time:
+    secs: int = attr.ib()
+    nsecs: int = attr.ib()
+
+    @staticmethod
+    def from_dict(d: Dict[str, Any]) -> 'Time':
+        return Time(d['secs'], d['nsecs'])
+
+    def to_dict(self) -> Dict[str, int]:
+        return {'secs': self.secs,
+                'nsecs': self.nsecs}

src/rozzy/definitions/type_db.py

@@ -6,6 +6,7 @@
 
 from .msg import MsgFormat
 from .format import FormatDatabase
+from .base import Time
 
 
 class Message:
@@ -14,6 +15,33 @@ class Message:
     """
     format: ClassVar[MsgFormat]
 
+    @staticmethod
+    def _to_dict_value(val: Any) -> Any:
+        typ = type(val)
+
+        if typ == Time or isinstance(typ, Message):
+            return val.to_dict()
+
+        if typ in (list, tuple):
+            if not typ:
+                return []
+            typ_item = type(typ[0])
+            if typ_item == Time or isinstance(typ_item, Message):
+                return [vv.to_dict() for vv in val]
+            # includes (str, int, float)
+            return list(val)
+
+        # includes (str, int, float)
+        return val
+
+    def to_dict(self) -> Dict[str, Any]:
+        d: Dict[str, Any] = {}
+        for field in self.format.fields:
+            name: str = field.name
+            val = getattr(self, field.name)
+            d[name] = self._to_dict_value(val)
+        return d
+
 
 class TypeDatabase(Mapping[str, Type[Message]]):
     @staticmethod

test/test_type_database.py

@@ -55,3 +55,19 @@ def test_build():
             t(foo='bar')
         with pytest.raises(TypeError):
             t('foo', 'bar')
+
+
+def test_to_dict():
+    s = """
+uint32 seq
+time stamp
+string frame_id
+    """
+    fmt = MsgFormat.from_string("PkgName", "MessageName", s)
+    t = TypeDatabase.build_type(fmt)
+
+    m = t(seq=310, stamp=Time(30, 120), frame_id='foo')
+    assert m.to_dict() == {
+        'seq': 310,
+        'stamp': {'secs': 30, 'nsecs': 120},
+        'frame_id': 'foo'}