url: https://github.com/fastapi/fastapi/discussions/categories/questions
  - name: Feature Request
    about: To suggest an idea or ask about a feature, please start with a question saying what you would like to achieve. There might be a way to do it already.
    url: https://github.com/fastapi/fastapi/discussions/categories/questions
  - name: Show and tell

### `scope`

The spec also says that the client can send another form field "`scope`".

The form field name is `scope` (in singular), but it is actually a long string with "scopes" separated by spaces.

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example:

* `users:read` or `users:write` are common examples.

We create an `HTTPException` that we can reuse (`raise`) later at several points.

In this exception, we include the scopes required (if any) as a string separated by spaces (using `scope_str`). We put that string containing the scopes in the `WWW-Authenticate` header (this is part of the spec).

### Check the code

* Check and read the code, see if it makes sense, **run it locally** and see if it actually solves the problem.

* Then **comment** saying that you did that, that's how I will know you really checked it.

/// info

Unfortunately, I can't simply trust PRs that just have several approvals.

					}
					fanOutEntries = append(fanOutEntries, m)
				}
				part.Close()
				continue
			}

			buf := bytebufferpool.Get()
			// value, store as string in memory
			n, err := io.CopyN(buf, part, maxMemoryBytes+1)
			value := buf.String()
			buf.Reset()
			bytebufferpool.Put(buf)
			part.Close()

			if err != nil && err != io.EOF {
				apiErr := errorCodes.ToAPIErr(ErrMalformedPOSTRequest)

A few special functions convert between Go and C types
by making copies of the data. In pseudo-Go definitions:

	// Go string to C string
	// The C string is allocated in the C heap using malloc.
	// It is the caller's responsibility to arrange for it to be
	// freed, such as by calling C.free (be sure to include stdlib.h
	// if C.free is needed).
	func C.CString(string) *C.char

	// Go []byte slice to C array

)

// Namer namer interface
type Namer interface {
	TableName(table string) string
	SchemaName(table string) string
	ColumnName(table, column string) string
	JoinTableName(joinTable string) string
	RelationshipFKName(Relationship) string
	CheckerName(table, column string) string
	IndexName(table, column string) string
	UniqueName(table, column string) string
}

// Replacer replacer interface like strings.Replacer

For any non-trivial change, we need to be able to answer these questions:

* Why is this change done? What's the use case?
* For user facing features, what will the API look like?
* What test cases should it have? What could go wrong?
* How will it roughly be implemented? We'll happily provide code pointers to save you time.

in each case in order to link to, bind by name, or subclass the Program
or Modified Works thereof.

"Distribute" means the acts of a) distributing or b) making available
in any manner that enables the transfer of a copy.

"Source Code" means the form of a Program preferred for making
modifications, including but not limited to software source code,
documentation source, and configuration files.

/// info

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

But if you have a bunch of dataclasses laying around, this is a nice trick to use them to power a web API using FastAPI. 🤓

///

## Dataclasses in `response_model`

You can also use `dataclasses` in the `response_model` parameter: