Query parameters

When you declare other function parameters that are not part of the path parameters, they are automatically interpreted as "query" parameters.

from typing import Annotated

from hattori import Response

weapons = ["Ninjato", "Shuriken", "Katana", "Kama", "Kunai", "Naginata", "Yari"]


@api.get("/weapons")
def list_weapons(
    request, limit: int = 10, offset: int = 0
) -> Annotated[Response[list[str]], 200]:
    return Response(200, weapons[offset : offset + limit])

To query this operation, you use a URL like:

http://localhost:8000/api/weapons?offset=0&limit=10

By default, all GET parameters are strings, and when you annotate your function arguments with types, they are converted to that type and validated against it.

The same benefits that apply to path parameters also apply to query parameters:

Editor support (obviously)
Data "parsing"
Data validation
Automatic documentation

Note

if you do not annotate your arguments, they will be treated as str types

@api.get("/weapons")
def list_weapons(request, limit, offset):
    # type(limit) == str
    # type(offset) == str

Defaults

As query parameters are not a fixed part of a path, they are optional and can have default values:

@api.get("/weapons")
def list_weapons(request, limit: int = 10, offset: int = 0):
    return weapons[offset : offset + limit]

In the example above we set default values of offset=0 and limit=10.

So, going to the URL:

http://localhost:8000/api/weapons

would be the same as going to:

http://localhost:8000/api/weapons?offset=0&limit=10

If you go to, for example:

http://localhost:8000/api/weapons?offset=20

the parameter values in your function will be:

offset=20 (because you set it in the URL)
limit=10 (because that was the default value)

Required and optional parameters

You can declare required or optional GET parameters in the same way as declaring Python function arguments:

from typing import Annotated

from hattori import Response

weapons = ["Ninjato", "Shuriken", "Katana", "Kama", "Kunai", "Naginata", "Yari"]


@api.get("/weapons/search")
def search_weapons(request, q: str, offset: int = 0) -> Annotated[Response[list[str]], 200]:
    results = [w for w in weapons if q in w.lower()]
    return Response(200, results[offset : offset + 10])

In this case, Django Ninja will always validate that you pass the q param in the GET, and the offset param is an optional integer.

GET parameters type conversion

Let's declare multiple type arguments:

from datetime import date
from typing import Annotated

from hattori import Response


@api.get("/example")
def example(
    request, s: str = None, b: bool = None, d: date = None, i: int = None
) -> Annotated[Response[list[str | bool | date | int | None]], 200]:
    return Response(200, [s, b, d, i])

The str type is passed as is.

For the bool type, all the following:

http://localhost:8000/api/example?b=1
http://localhost:8000/api/example?b=True
http://localhost:8000/api/example?b=true
http://localhost:8000/api/example?b=on
http://localhost:8000/api/example?b=yes

or any other case variation (uppercase, first letter in uppercase, etc.), your function will see the parameter b with a bool value of True, otherwise as False.

Date can be both date string and integer (unix timestamp):

http://localhost:8000/api/example?d=1577836800  # same as 2020-01-01
http://localhost:8000/api/example?d=2020-01-01

Using Schema

You can also use Schema to encapsulate GET parameters:

from typing import Annotated

from hattori import Query, Response, Schema


class Filters(Schema):
    limit: int = 100
    offset: int | None = None
    query: str | None = None
    categories: list[str] | None = None


class FilterResponse(Schema):
    filters: Filters


@api.get("/filter")
def events(request, filters: Query[Filters]) -> Annotated[Response[FilterResponse], 200]:
    return Response(200, {"filters": filters})

For more complex filtering scenarios please refer to filtering.