### 无需注解 { #no-annotation }

你其实不需要为流式二进制数据声明返回类型注解。

由于 FastAPI 不会使用 Pydantic 将数据转换为 JSON，也不会以任何方式序列化，在这种情况下，类型注解只供你的编辑器和工具使用，FastAPI 不会使用它。

{* ../../docs_src/stream_data/tutorial001_py310.py ln[32:35] hl[33] *}

这也意味着，使用 `StreamingResponse` 时，你拥有按需精确生成与编码字节数据的自由，同时也承担相应的责任，它与类型注解无关。🤓

### 流式传输字节 { #stream-bytes }

主要的用例之一是流式传输 `bytes` 而不是字符串，这当然可以做到。

    assertThat(formEncode(30)).isEqualTo("%1E")
    assertThat(formEncode(31)).isEqualTo("%1F")
    // Browsers use '+' for space.
    assertThat(formEncode(32)).isEqualTo("+")
    assertThat(formEncode(33)).isEqualTo("%21")
    assertThat(formEncode(34)).isEqualTo("%22")
    assertThat(formEncode(35)).isEqualTo("%23")
    assertThat(formEncode(36)).isEqualTo("%24")
    assertThat(formEncode(37)).isEqualTo("%25")

{* ../../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`.

///

* `swagger_css_url`: the URL where the HTML for your Swagger UI docs can get the **CSS** file. This is the custom CDN URL.

And similarly for ReDoc...

{* ../../docs_src/custom_docs_ui/tutorial001_py310.py hl[2:6,11:19,22:24,27:33] *}

/// tip

The *path operation* for `swagger_ui_redirect` is a helper for when you use OAuth2.

Sebastián Ramírez <******@****.***> 1773946599 +0100

Yuri Schimke <******@****.***> 1756571139 +0100

                            JvmCategory.MIN_VERSION,
                            DEFAULT_LINUX_FUNCTIONAL_TEST_BUCKET_SIZE,
                        ),
                        TestCoverage(
                            33,
                            TestType.ALL_VERSIONS_INTEG_MULTI_VERSION,
                            Os.LINUX,
                            JvmCategory.MIN_VERSION,
                            ALL_CROSS_VERSION_BUCKETS.size,

	ADD	$0x3fffffffc000, R5             // ADD	$70368744161280, R5               // fb7f72b2a5001b8b
	ADD	R1>>11, R2, R3
	ADD	R1<<22, R2, R3
	ADD	R1->33, R2, R3
	AND	R1@>33, R2, R3
	ADD	R1.UXTB, R2, R3                 // 4300218b
	ADD	R1.UXTB<<4, R2, R3              // 4310218b
	ADD	R2, RSP, RSP                    // ff63228b
	ADD	R2.SXTX<<1, RSP, RSP            // ffe7228b

Harshavardhana <******@****.***> 1723451895 -0700

        // Mock times (8 bytes each)
        for (int i = 0; i < 32; i++) {
            buffer[i] = (byte) (i % 256);
        }

        // Mock attributes (4 bytes)
        buffer[32] = 0x01;
        buffer[33] = 0x00;
        buffer[34] = 0x00;
        buffer[35] = 0x00;

        return buffer;
    }

    private byte[] createMockFileStandardInfoBuffer() {