This prevents potential cross-site request forgery (CSRF) attacks
                that exploit the browser's ability to send requests without a
                Content-Type header, bypassing CORS preflight checks. In particular
                applicable for apps that need to be run locally (in localhost).

                When `False`, requests without a `Content-Type` header will have

{* ../../docs_src/behind_a_proxy/tutorial002_py310.py hl[3] *}

Passing the `root_path` to `FastAPI` would be the equivalent of passing the `--root-path` command line option to Uvicorn or Hypercorn.

### About `root_path` { #about-root-path }

Keep in mind that the server (Uvicorn) won't use that `root_path` for anything else than passing it to the app.

For those cases, you can use the `jsonable_encoder` to convert your data before passing it to a response:

{* ../../docs_src/response_directly/tutorial001_py310.py hl[5:6,20:21] *}

/// note | Technical Details

You could also use `from starlette.responses import JSONResponse`.

///

The only thing the function returned by `GzipRequest.get_route_handler` does differently is convert the `Request` to a `GzipRequest`.

Doing this, our `GzipRequest` will take care of decompressing the data (if necessary) before passing it to our *path operations*.

After that, all of the processing logic is the same.

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

```console
$ pip install httpx
```

///

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.

#       space-separated string is a well documented source of bugs and security
#       problems, so this is (mostly) avoided, by progressively accumulating
#       options in "$@", and eventually passing that to Java.
#
#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
#       see the in-line comments for details.
#

    assertThat(Strings.lenientFormat(null, 5, 6)).isEqualTo("null [5, 6]");
    assertThat(Strings.lenientFormat("%s", (Object) null)).isEqualTo("null");
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testLenientFormat_nullArrayVarargs() {
    assertThat(Strings.lenientFormat("%s", (Object[]) null)).isEqualTo("(Object[])null");
  }

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[33] *}

/// tip

Notice that you are not passing the router itself (`invoices_callback_router`) to `callback=`, but the attribute `.routes`, as in `invoices_callback_router.routes`.

///

### Check the docs { #check-the-docs }

with `yield`.

For example, instead of using the same database session, you would create a new database session inside of the background task, and you would obtain the objects from the database using this new session. And then instead of passing the object from the database as a parameter to the background task function, you would pass the ID of that object and then obtain the object again inside the background task function....

Then you can use the new `settings` object in your application:

{* ../../docs_src/settings/tutorial001_py310.py hl[18:20] *}

### Run the server { #run-the-server }

Next, you would run the server passing the configurations as environment variables, for example you could set an `ADMIN_EMAIL` and `APP_NAME` with:

<div class="termy">

```console
$ ADMIN_EMAIL="******@****.***" APP_NAME="ChimichangApp" fastapi run main.py