{!../../docs_src/custom_response/tutorial007.py!}
```

#### Using `StreamingResponse` with file-like objects

If you have a file-like object (e.g. the object returned by `open()`), you can create a generator function to iterate over that file-like object.

That way, you don't have to read it all first in memory, and you can pass that generator function to the `StreamingResponse`, and return it.

<div class="termy">

```console
$ pip install websockets

---> 100%
```

</div>

## WebSockets-Client

### In Produktion

In Ihrem Produktionssystem haben Sie wahrscheinlich ein Frontend, das mit einem modernen Framework wie React, Vue.js oder Angular erstellt wurde.

          return new IteratorWithSunJavaBug6529795<>(iterator);
        }
      }.test();
    } catch (AssertionError e) {
      return;
    }
    fail("Should have caught jdk6 bug in target iterator");
  }

  private static final int STEPS = 3;

  static class TesterThatCountsCalls extends IteratorTester<Integer> {
    TesterThatCountsCalls() {

    }
  }

  override fun loadForRequest(url: HttpUrl): List<Cookie> {
    val cookieHeaders =
      try {
        // The RI passes all headers. We don't have 'em, so we don't pass 'em!
        cookieHandler.get(url.toUri(), emptyMap<String, List<String>>())
      } catch (e: IOException) {
        Platform.get().log("Loading cookies failed for " + url.resolve("/...")!!, WARN, e)

======================

Square recognizes the important contributions the security research community
can make. We therefore encourage reporting security issues with the code
contained in this repository.

If you believe you have discovered a security vulnerability, please follow the

then fixing the bug will break that code.
New features can also have similar impacts:
enabling the HTTP/2 use by the HTTP client broke programs
connecting to servers with buggy HTTP/2 implementations.
These kinds of changes are unavoidable and
[permitted by the Go 1 compatibility rules](/doc/go1compat).
Even so, Go provides a mechanism called GODEBUG to
reduce the impact such changes have on Go developers
using newer toolchains to compile old code.

## Using the `jsonable_encoder` in a `Response`

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.

* It can do something to that **response** or run any needed code.
* Then it returns the **response**.

/// note | "Technical Details"

If you have dependencies with `yield`, the exit code will run *after* the middleware.

If there were any background tasks (documented later), they will run *after* all the middleware.

///

## Create a middleware

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package json

import (
	"io"
	"sync"

Two new interfaces, [TextAppender] and [BinaryAppender], have been
introduced to append the textual or binary representation of an object
to a byte slice. These interfaces provide the same functionality as
[TextMarshaler] and [BinaryMarshaler], but instead of allocating a new slice