# カスタムレスポンス - HTML、ストリーム、ファイル、その他 { #custom-response-html-stream-file-others }

デフォルトでは、**FastAPI** はJSONレスポンスを返します。

[レスポンスを直接返す](response-directly.md)で見たように、`Response` を直接返してこの挙動を上書きできます。

しかし、`Response`（または `JSONResponse` のような任意のサブクラス）を直接返す場合、（`response_model` を宣言していても）データは自動的に変換されず、ドキュメントも自動生成されません（例えば、生成されるOpenAPIの一部としてHTTPヘッダー `Content-Type` に特定の「メディアタイプ」を含めるなど）。

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

pkg go/types, method (*Chan) Elem() Type
pkg go/types, method (*Chan) String() string
pkg go/types, method (*Chan) Underlying() Type
pkg go/types, method (*Checker) Files([]*ast.File) error
pkg go/types, method (*Config) Check(string, *token.FileSet, []*ast.File, *Info) (*Package, error)
pkg go/types, method (*Const) Exported() bool
pkg go/types, method (*Const) Id() string
pkg go/types, method (*Const) Name() string

pkg io/fs, type DirEntry interface, Type() FileMode
pkg io/fs, type FS interface { Open }
pkg io/fs, type FS interface, Open(string) (File, error)
pkg io/fs, type File interface { Close, Read, Stat }
pkg io/fs, type File interface, Close() error
pkg io/fs, type File interface, Read([]uint8) (int, error)
pkg io/fs, type File interface, Stat() (FileInfo, error)
pkg io/fs, type FileInfo interface { IsDir, ModTime, Mode, Name, Size, Sys }

/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright (C) 2014 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

   * "e"]}. The last piece can be smaller than {@code length} but will never be empty.
   *
   * <p><b>Note:</b> if {@link #fixedLength} is used in conjunction with {@link #limit}, the final
   * split piece <i>may be longer than the specified fixed length</i>. This is because the splitter
   * will <i>stop splitting when the limit is reached</i>, and just return the final piece as-is.
   *

/*
 * Copyright (C) 2011 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License

// another n bytes. After Grow(n), at least n bytes can be written to the
// buffer without another allocation.
// If n is negative, Grow will panic.
// If the buffer can't grow it will panic with [ErrTooLarge].
func (b *Buffer) Grow(n int) {
	if n < 0 {
		panic("bytes.Buffer.Grow: negative count")
	}
	m := b.grow(n)
	b.buf = b.buf[:m]
}