Creating Enum class from dictionary about fastapi

[justindujardin]

This came up on Google before any pydantic thread, so for anyone else looking it's surprisingly easy:

from pydantic import BaseModel
from enum import Enum
custom_enum_values = {
    "cool": "stuff", 
    "other": "thing",
    "foo": "fighters"
}
TypeEnum = Enum("TypeEnum", custom_enum_values)
class CustomModel(BaseModel):
    type: TypeEnum = TypeEnum.cool

a = CustomModel()
print(a.type.name)  # 'cool'
print(a.type.value)  # 'stuff'

b = CustomModel(type="fighters")
print(f"{b.type.name.capitalize()} {b.type.value.capitalize()}") # 'Foo Fighters'

[saveshodhan]

@justindujardin's method works, but in my case it somehow didnt show the enum values in OpenAPI docs schemas.
This SO answer says that's because the class does not inherit from str as well.

As a workaround, I created a temp class that inherits from both, str as well as Enum, and then applied the same technique mentioned by @justindujardin. This then showed up in the docs as well:

class TempEnum(str, Enum):
    pass

TypeEnum = TempEnum("TypeEnum", custom_enum_values)

[tiangolo]

In theory, you could create an enum dynamically with the functional API: https://docs.python.org/3/library/enum.html#functional-api

And then you could use that with Pydantic dynamic's create_model with that dynamic enum.

I haven't personally tried it yet 😅 .

---

Nevertheless, if the possible values are "unbounded", if they can be a lot (stored in MongoDB), it might end up being better to use a frontend-side auto-completion widget, with search connected to the API, that then sends the query to MogoDB and keeps filtering the selectable values. Otherwise, you could have a very long select in the front end, that apart from looking ugly could make the browser unresponsive, etc.

[tiangolo]

I assume you solved your problem so I'll close this issue now. But feel free to add more comments or create new issues.

[VianneyMI]

@zero0nee @tiangolo
I have a similar use case and implemented something as described in this thread.
Now, my question is how can I make this truly dynamic i.e refresh the dynamic enums as updates are made to my database

[myuanz]

@zero0nee @tiangolo I have a similar use case and implemented something as described in this thread. Now, my question is how can I make this truly dynamic i.e refresh the dynamic enums as updates are made to my database

You can try this: https://gist.github.com/myuanz/03f3e350fb165ec3697a22b559a7eb50

[github-actions]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.