///

```Python hl_lines="10"
{!> ../../docs_src/request_form_models/tutorial002.py!}
```

////

If a client tries to send some extra data, they will receive an **error** response.

For example, if the client tries to send the form fields:

* `username`: `Rick`
* `password`: `Portal Gun`
* `extra`: `Mr. Poopybutthole`

	buf.WriteString("Stats")

	fmt.Println(buf.Bytes())
}

// End Message
// ===========
// Header specification
// --------------------
// End messages contain two headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-end.png
//
// Payload specification
// ---------------------
// End messages have no payload.
func genEndMessage() {
	buf := new(bytes.Buffer)

# 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

		_, err := f.Write(chunk[:frag])
		if err != nil {
			t.Fatal("write chunk:", err)
		}
	}
	end := []byte("END\n")
	_, err = f.Write(end)
	if err != nil {
		t.Fatal("write end:", err)
	}
	if err := w.Close(); err != nil {
		t.Fatal(err)
	}

	// read back zip file and check that we get to the end of it
	r, err := NewReader(buf, buf.Size())
	if err != nil {
		t.Fatal("reader:", err)
	}

                "msg": "Value error, name must end in A",
                "input": "modelX",
                "ctx": {"error": HasRepr("ValueError('name must end in A')")},
            }
        )
        | IsDict(
            # TODO remove when deprecating Pydantic v1
            {
                "loc": ("response", "name"),
                "msg": "name must end in A",
                "type": "value_error",
            }

    // enclosed with same end
    assertEquals(Range.closed(6, 8), range.intersection(Range.closed(6, 8)));

    // equal
    assertEquals(range, range.intersection(range));

    // enclosing with same start
    assertEquals(range, range.intersection(Range.closed(4, 10)));

    // enclosing with same end
    assertEquals(range, range.intersection(Range.closed(2, 8)));

except.txt lists features that may disappear without breaking true
compatibility.

Starting with go1.19.txt, each API feature line must end in "#nnnnn"
giving the GitHub issue number of the proposal issue that accepted
the new API. This helps with our end-of-cycle audit of new APIs.
The same requirement applies to next/* (described below), which will
become a go1.XX.txt for XX >= 19.

        }

        int r, n;
        SmbComReadAndXResponse response = new SmbComReadAndXResponse( b, off );
        do {
            r = len > readSize ? readSize : len;
            file.send( new SmbComReadAndX( file.fid, fp, r, null ), response );
            if(( n = response.dataLength ) <= 0 ) {
                return (int)((fp - start) > 0L ? fp - start : -1);
            }
            fp += n;

	column, values := schema.ToQueryValues(clause.CurrentTable, relForeignKeys, foreignValues)

	if len(values) != 0 {
		for _, cond := range conds {
			if fc, ok := cond.(func(*gorm.DB) *gorm.DB); ok {
				tx = fc(tx)
			} else {
				inlineConds = append(inlineConds, cond)
			}
		}

The user of your API (an external developer) will create an invoice in your API with a POST request.

Then your API will (let's imagine):

* Send the invoice to some customer of the external developer.
* Collect the money.
* Send a notification back to the API user (the external developer).