OpenAPI deepObject serialization for query parameters

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Description

Allow usage of deepObject serialization from OpenAPI 3.

What it could look like

from fastapi import FastAPI

app = FastAPI()

class UserQuery(BaseModel):
    role: str
    firstName: str

@app.get("/")
def read_root(id: Optional[UserQuery]):
    return {"Hello": "World"}

Query:

/users?id[role]=admin&id[firstName]=Alex

Related

• https://github.com/tiangolo/fastapi/issues/245#issuecomment-762729917
  • Links to a good example: https://stackoverflow.com/questions/48491688/how-to-define-parameters-with-square-brackets-in-openapi-swagger
• https://github.com/tiangolo/fastapi/issues/203

[adriangb]

How about just Query(style="deepObject")?

[sm-Fifteen]

See also #283 for broader support of encoding styles.

This is the sort of issue where it’s not entirely clear if the responsibility of supporting this should be on FastAPI or Pydantic. On one hand, it has to do with value parsing and encoding, which is something FastAPI tends to fully delegate to Pydantic, but on the other hand it’s not part of JSON Schema, it’s an OpenAPI extension that only applies to route parameter objects, and most of these encoding styles don’t make sense in a JSON context (which is what pydantic is generally meant for).

I would like to see these supported as well.