Fastapi: Creating Enum class from dictionary

[zero0nee]

I want the user to be able to select parameter values from an enum list of values as a dropdown in the swagger documentation.

The only way, to my knowledge, to do that is to create a Enum pydantic class, and designate a parameter as a part of that class. Which is fine. But in my situation, I want the enum to be dynamically generated based on all unique document values of a property stored in a MongoDB collection. I think you can create a BaseModel class dynamically using the create_model() function, but as far as I know that's not possible with a Enum class.

So my question is: How can I create a parameter enumeration in Swagger from all values in a mongDb collection?

[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 :sweat_smile: .

---

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.

[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'