Optional Query parameter list

[jorgejesus]

First check

• [ x] I used the GitHub search to find a similar issue and didn't find it.
• [ x] I searched the FastAPI documentation, with the integrated search.
• [ x] I already searched in Google "How to X in FastAPI" and didn't find any information.

Description

Documentation is very clear that we can use lists e,g

@app.get("/")
async def my_query(q: List[str] = Query(["a","b","c","d"])):

How can I:
Have an optional list structure, from the documentation we include the key word None
e.g:

values:str = None

Meaning we can have two scenarios:

• /q=a&q=b (q is present and item is in list)
• / (q is not present)

Tryied: Query(None,["a","b","c","d"]) but it didnt worked

Additional context

Using fastapi==0.49.0

[phy25]

Not sure if you want the default to be None why you want ["a","b","c","d"] to be a default as well. You can try typing.Optional[typing.List] = Query(["a","b","c","d"]).

[jorgejesus]

My apologies since we have the following note:

Have in mind that in this case, FastAPI won't check the contents of the list.

Therefore there is no problem on missing the q (and its content) on the query

[tiangolo]

Thanks for the help here @phy25 ! 🙇‍♂️

Thanks for reporting back and closing the issue @jorgejesus 👍