# `FastAPI` class

Here's the reference information for the `FastAPI` class, with all its parameters, attributes and methods.

You can import the `FastAPI` class directly from `fastapi`:

```python
from fastapi import FastAPI
```

::: fastapi.FastAPI
    options:
        members:
            - openapi_version
            - webhooks
            - state
            - dependency_overrides
            - openapi

from typing import Annotated

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: Annotated[bytes, File(description="A file read as bytes")]):
    return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(
    file: Annotated[UploadFile, File(description="A file read as UploadFile")],
):

     * If an exception occurs in the try block, there is a possibility that an exception will also occur in the finally block's {@link #close(Closeable)}. If the exception is thrown from the finally block, the original exception from the try block will be lost.
     * </p>
     *
     * @param closeable the closeable object
     * @see Closeable#close()
     */
    public static void close(final Closeable closeable) {
        if (closeable == null) {

@SuppressWarnings("checkstyle:UnusedLocalVariable")
class ProjectInheritanceTest extends AbstractProjectInheritanceTestCase {
    // ----------------------------------------------------------------------
    //
    // p1 inherits from p0
    // p0 inherits from super model
    //
    // or we can show it graphically as:
    //
    // p1 ---> p0 --> super model
    //
    // ----------------------------------------------------------------------

    @Test

import importlib

import pytest
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial005_py39"),
        pytest.param("tutorial005_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.response_model.{request.param}")

import importlib

import pytest
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial006_py39"),
        pytest.param("tutorial006_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.response_model.{request.param}")

import pytest
from fastapi import APIRouter, FastAPI
from fastapi.routing import APIRoute
from fastapi.testclient import TestClient
from starlette.routing import Route

app = FastAPI()


class APIRouteA(APIRoute):
    x_type = "A"


class APIRouteB(APIRoute):
    x_type = "B"


class APIRouteC(APIRoute):
    x_type = "C"


router_a = APIRouter(route_class=APIRouteA)
router_b = APIRouter(route_class=APIRouteB)

/**
 * Extracts text content and metadata from Markdown files.
 * This extractor provides better structured data extraction compared to Tika's generic text extraction.
 *
 * <p>Features:
 * <ul>
 *   <li>YAML front matter metadata extraction</li>
 *   <li>Heading structure extraction</li>
 *   <li>Link URL extraction</li>
 *   <li>Code block content extraction</li>
 *   <li>Clean text conversion from Markdown</li>

from typing import Annotated, Optional

import pytest
from fastapi import FastAPI, Form
from fastapi.testclient import TestClient
from pydantic import BaseModel, Field

from .utils import get_body_model_name

app = FastAPI()

# =====================================================================================
# Without aliases


@app.post("/optional-str", operation_id="optional_str")

from typing import Annotated

import pytest
from dirty_equals import IsOneOf
from fastapi import FastAPI, Query
from fastapi.testclient import TestClient
from pydantic import BaseModel, Field

app = FastAPI()

# =====================================================================================
# Without aliases


@app.get("/required-str")
async def read_required_str(p: str):
    return {"p": p}