marshmallow_dataclass
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lovasoa
Add example of enum usage to documentation
It is specified in the documentation to use pip3 install "marshmallow-dataclass[enum,union]"
However whenever an enum field is used with the dataclass I'm getting a ['Enum name must be string'] error. I have tried several different ways of writing my enum class, and whilst I'm sure I'll get there it isn't immediately obvious how to use the enum feature with dataclasses.
A couple of lines in a readme file would fix this and be greatly appreciated.
Hello, Can you include the failing code sample triggering the Enum name must be string error ?
Hello - it's less a code issue and more a lack of an example in the documentation issue. Took me a while to work out how to add the enum field to the dataclass. Really nice work on the library.
I've got to the bottom of it - want me to start a pull request with documentation changes?
Essentially it's the following:
class TrafficLight(Enum):
RED = "RED"
GREEN = "GREEN"
BLUE = "BLUE"
@dataclass()
class MyLovelyMarshmallowDataclass:
id: str
status: str = EnumField(TrafficLight)
I've got to the bottom of it - want me to start a pull request with documentation changes?
If you can, that would be great !
The canonical way to do it should be
class TrafficLight(Enum):
RED = "RED"
GREEN = "GREEN"
BLUE = "BLUE"
@dataclass()
class MyLovelyMarshmallowDataclass:
id: str
status: TrafficLight
I had the same issue today, my enum was in the format:
class TrafficLight(Enum):
RED = "red", "RED"
GREEN = "green", "GREEN"
BLUE = "blue", "BLUE"
I had to use the following
@dataclass()
class MyLovelyMarshmallowDataclass:
id: str
status: set
Any workaround to be able to use directly status: TrafficLight instead of status: set (I don't need a default)? Seems that when it gets by name, EnumField tries to check if it's a string and it fails otherwise.
Yes, it does need to be a string ? If what you want is a set if TrafficLights, then just give it the type Set[TrafficLights].
Yes, it does need to be a string ? If what you want is a set if TrafficLights, then just give it the type
Set[TrafficLights].
Unfortunately that doesn't work, it throws TypeError: typing.Set[TrafficLight] is not a dataclass and cannot be turned into one.
How do I mention a default value for a dataclass field when using EnumField?
This has always worked for me:
class Color(Enum):
RED = auto()
GREEN = auto()
BLUE = auto()
@dataclass
class Thing:
color: Color = Color.RED
This has always worked for me:
class Color(Enum): RED = auto() GREEN = auto() BLUE = auto() @dataclass class Thing: color: Color = Color.RED
Just an important observation: if you follow this approach, the schema.load() will expect by default the field for "color" to be a string. Example:
schema = Thing.Schema()
schema.load({ "color": Color.RED }) # this will throw a ValidationError
schema.load({ "color": Color.RED.name }) # this will work.
If you want schema.load({ "color": Color.RED }) to work, you need to pass the option "by_value": True as such:
@dataclass
class Thing:
color: Color = field(default=Color.RED, metadata={"by_value": True})
I think this should be mentioned in the documentation because it seems that the default behavior differs from the one in mashmallow-enum, at least according to their README.
The default behavior of mashmallow-enum is by_value=False. Its readme is not specifying this behavior.
We have many Enums and in our case they should be serialized by value. This means that we have to add metadata={"by_value": True} to each field.
It would be great if one could set this parameter for all Enums or to specify a different Enum class for the whole schema generation process.
If I run
class Color(Enum):
RED = auto()
GREEN = auto()
BLUE = auto()
@dataclass
class Thing:
color: Color = Color.RED
the field doesn't appear on swagger UI, but
The less canonical version
class Color(Enum):
RED = auto()
GREEN = auto()
BLUE = auto()
@dataclass
class Thing:
color: str= Color.RED.value
works correctly.
Do you know if this is the expected behavior or there's an outstanding missing support in swagger-ui for enums?
We have many Enums and in our case they should be serialized by value. This means that we have to add metadata={"by_value": True} to each field. It would be great if one could set this parameter for all Enums or to specify a different Enum class for the whole schema generation process.
You can use NewType, or a custom base Schema
Is there any workaround related to this when using pure python dataclasses?
We have many Enums and in our case they should be serialized by value. This means that we have to add metadata={"by_value": True} to each field. It would be great if one could set this parameter for all Enums or to specify a different Enum class for the whole schema generation process.
You can use NewType, or a custom base Schema
Would it be possible to have a sample of a working code that uses enum specifically as a reference? Also, somewhat related to the whole enum theme. I ran into issues trying to define a dataclass with a property that is a List of enums. I don't seem to be able to figure out how to pass metadata to the list element constructor.
How to perform similar to above for a list of colors, e.g.:
@dataclass
class Thing:
color: list[Color] = field(default=Color.RED, metadata={"by_value": True})
https://github.com/lovasoa/marshmallow_dataclass/issues/255
