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Example Codefrom fastapi import FastAPI
app = FastAPI()
@app.get("/")
def root(
q: int | None = Query(None),
):
return qDescriptionOpen Operating SystemLinux Operating System DetailsNo response FastAPI Version0.105.0 Pydantic Version2.5.3 Python Version3.11.7 Additional ContextNo response |
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Replies: 3 comments 8 replies
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Use Annotated like from fastapi import FastAPI, Query
from typing import Annotated
app = FastAPI()
@app.get("/")
def root(q: Annotated[int, Query()] = None):
return q
|
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Look at this: #10781 (comment) As that comment says, it depends on how those pages choose to render the schema. |
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It didn't help me to understand how to correctly define optional query param. So, there is definitely a bug in fastapi or pydantic |
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The problem with p1 lies in its allowance of a null value, which is not reflected in the openapi.json. P1 represents the oldest openapi generated schema, and Swagger is capable of displaying this information because there is only one type for the query parameter in the generated schema, even though it permits a null value. However, with the corrected openapi schema as p2, there are now two types for the same parameter. I suppose Swagger doesn't know how to display that information, but you can see that in /redoc that query parameter would be an integer or null. That's what I mean by it depends on how those pages decide to render the schema |
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Thanks, I got it. And it helps me to find several issues about it and one hack solution. Using q: Annotated[int | SkipJsonSchema[None], Query()] = None
#9709 (reply in thread) It seems like swagger doesn't support anyOf for parameters |
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btw will be nice to see this solution or problem description somewhere in docs, this is a stopper of using p2 for me |
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@tiangolo |
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@tiangolo
I don't think FastAPI(or maybe OpenAPI) has a way to accept null in queries. |
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So I came across this issue from the docs here: which say that: from typing import Annotated
from fastapi import FastAPI, Query
app = FastAPI()
@app.get("/items/")
async def read_items(q: Annotated[list[str] | None, Query()] = None):
query_items = {"q": q}
return query_itemsshould produce an array in Swagger UI/OpenAPI, which did not happen. remove the optional "None" type hint: from typing import Annotated
from fastapi import FastAPI, Query
app = FastAPI()
@app.get("/items/")
async def read_items(q: Annotated[list[str], Query()] = None):
query_items = {"q": q}
return query_itemsor downgrade pydantic:
However the current docs situation is quite bad for this, even if this is not a FastAPI issue originally. Using Redoc UI at |
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There is also #10481 as a similar discussion. In Pydantic, there is this issue: pydantic/pydantic#6647 which resulted in an additional wrapper: from pydantic import SkipJsonSchema
@app.get("/items/")
async def read_items(q: Annotated[list[str] | SkipJsonSchema[None], Query()] = None):
query_items = {"q": q}
return query_itemswhich is not very well either. Swagger somehow seems to support There is also as FastAPI related PR in #9873 |
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Thanks, I got it. And it helps me to find several issues about it and one hack solution.
Using
SkipJsonSchemaremoves anyOf and null from openapi.json and swagger shows parameter correctly"parameters":[{"name":"q","in":"query","required":false,"schema":{"type":"integer","title":"Q"}}]#9709 (reply in thread)
pydantic/pydantic#6653 (comment)
It seems like swagger doesn't support anyOf for parameters