from fastapi import FastAPI, HTTPException
from fastapi.exception_handlers import (
    http_exception_handler,
    request_validation_exception_handler,
)
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException

app = FastAPI()


@app.exception_handler(StarletteHTTPException)
async def custom_http_exception_handler(request, exc):
    print(f"OMG! An HTTP error!: {repr(exc)}")

from typing import List, Optional, Union

import pytest
from fastapi import FastAPI
from fastapi.exceptions import ResponseValidationError
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: Optional[float] = None
    owner_ids: Optional[List[int]] = None


@app.get("/items/invalid", response_model=Item)
def get_invalid():

from typing import Union

from fastapi import FastAPI
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Union[str, None] = None
    description: Union[str, None] = None
    price: Union[float, None] = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},

   */
  private static void movePivotToStartOfSlice(double[] array, int from, int to) {
    int mid = (from + to) >>> 1;
    // We want to make a swap such that either array[to] <= array[from] <= array[mid], or
    // array[mid] <= array[from] <= array[to]. We know that from < to, so we know mid < to
    // (although it's possible that mid == from, if to == from + 1). Note that the postcondition

		case "linux":
			// Copied from golang.org/x/sys/unix/dev_linux.go.
			major := uint32((dev & 0x00000000000fff00) >> 8)
			major |= uint32((dev & 0xfffff00000000000) >> 32)
			minor := uint32((dev & 0x00000000000000ff) >> 0)
			minor |= uint32((dev & 0x00000ffffff00000) >> 12)
			h.Devmajor, h.Devminor = int64(major), int64(minor)
		case "darwin", "ios":
			// Copied from golang.org/x/sys/unix/dev_darwin.go.

    assertEquals("google.com", InternetDomainName.from("www.google.com").parent().toString());

    try {
      InternetDomainName.from("com").parent();
      fail("'com' should throw ISE on .parent() call");
    } catch (IllegalStateException expected) {
    }
  }

  public void testChild() {
    InternetDomainName domain = InternetDomainName.from("foo.com");

import pytest
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.dependencies.tutorial008d_an import app

    client = TestClient(app)
    return client


def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text
    assert response.json() == {"detail": "Item not found, there's only a plumbus here"}

from ...utils import needs_py39


@needs_py39
def test_override_in_items_run():
    from docs_src.dependency_testing.tutorial001_an_py39 import test_override_in_items

    test_override_in_items()


@needs_py39
def test_override_in_items_with_q_run():
    from docs_src.dependency_testing.tutorial001_an_py39 import (
        test_override_in_items_with_q,
    )

    test_override_in_items_with_q()


@needs_py39

		Result  string
		Vars    []interface{}
	}{
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.OrderBy{
				Columns: []clause.OrderByColumn{{Column: clause.PrimaryColumn, Desc: true}},
			}},
			"SELECT * FROM `users` ORDER BY `users`.`id` DESC", nil,
		},
		{
			[]clause.Interface{
				clause.Select{}, clause.From{}, clause.OrderBy{
					Columns: []clause.OrderByColumn{{Column: clause.PrimaryColumn, Desc: true}},

# WebSockets

When defining WebSockets, you normally declare a parameter of type `WebSocket` and with it you can read data from the client and send data to it.

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

!!! tip