from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    app_name: str = "Awesome API"
    admin_email: str

    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: str | None = Query(default=None, min_length=3, max_length=50)):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[Union[str, None], Query(min_length=3, max_length=50)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None, Query(min_length=3, max_length=50, regex="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

```

////

Notice that the default value is still `None`, so the parameter is still optional.

But now, having `Query(max_length=50)` inside of `Annotated`, we are telling FastAPI that we want it to have **additional validation** for this value, we want it to have maximum 50 characters. 😎

/// tip

                    <mxGeometry relative="1" as="geometry">
                        <mxPoint x="50" y="500" as="sourcePoint"/>
                        <Array as="points">
                            <mxPoint x="50" y="740"/>
                        </Array>
                    </mxGeometry>
                </mxCell>

        final CrawlerWebServer server = new CrawlerWebServer(7070);
        server.start();

        final String url = "http://localhost:7070/";
        try {
            final int maxCount = 50;
            final int numOfThread = 10;

            final File file = File.createTempFile("crawler-", "");
            file.delete();
            file.mkdirs();
            file.deleteOnExit();

from fastapi import FastAPI
from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    app_name: str = "Awesome API"
    admin_email: str
    items_per_user: int = 50


settings = Settings()
app = FastAPI()


@app.get("/info")
async def info():
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

name: Issue Workflow

on:
  issues:
    types:
      - opened

jobs:
  add-to-project:
    name: Add issue to project
    runs-on: ubuntu-latest
    steps:
      - uses: actions/add-to-project@v0.5.0
        with:
          project-url: https://github.com/orgs/miniohq/projects/2