exchange.responseHeadersStart()
          invokeStartEvent = false
        }
        if (responseBuilder == null) {
          if (requestBody.isDuplex()) {
            // Prepare a duplex body so that the application can send a request body later.
            exchange.flushRequest()
            val bufferedRequestBody = exchange.createRequestBody(request, true).buffer()
            requestBody.writeTo(bufferedRequestBody)
          } else {

   *
   * The route is best effort, it currently may not always be provided even when logically
   * available. It may also not be provided when an authenticator is re-used manually in an
   * application interceptor, such as when implementing client-specific retries.
   */
  @Throws(IOException::class)
  fun authenticate(
    route: Route?,
    response: Response,
  ): Request?

  companion object {

import okhttp3.CookieJar
import okhttp3.Interceptor
import okhttp3.Response
import okhttp3.internal.USER_AGENT
import okhttp3.internal.toHostHeader
import okio.GzipSource
import okio.buffer

/**
 * Bridges from application code to network code. First it builds a network request from a user
 * request. Then it proceeds to call the network. Finally it builds a user response from the network
 * response.
 */
class BridgeInterceptor : Interceptor {

   * never mutated once it has been assigned.
   */
  var peerSettings = DEFAULT_SETTINGS

  /** The bytes consumed and acknowledged by the application. */
  val readBytes: WindowCounter = WindowCounter(streamId = 0)

  /** The total number of bytes produced by the application. */
  var writeBytesTotal = 0L
    private set

  /** The total number of bytes permitted to be produced according to `WINDOW_UPDATE` frames. */

/// info

Webhooks are available in OpenAPI 3.1.0 and above, supported by FastAPI `0.99.0` and above.

///

## An app with webhooks { #an-app-with-webhooks }

When you create a **FastAPI** application, there is a `webhooks` attribute that you can use to define *webhooks*, the same way you would define *path operations*, for example with `@app.webhooks.post()`.

    if (path.endsWith(".gif")) return "image/gif";
    if (path.endsWith(".html")) return "text/html; charset=utf-8";
    if (path.endsWith(".txt")) return "text/plain; charset=utf-8";
    return "application/octet-stream";
  }

  public static void main(String[] args) throws Exception {
    if (args.length != 4) {
      System.out.println("Usage: SampleServer <keystore> <password> <root file> <port>");
      return;

# 严格的 Content-Type 检查 { #strict-content-type-checking }

默认情况下，FastAPI 对 JSON 请求体使用严格的 `Content-Type` 头检查。这意味着，JSON 请求必须包含有效的 `Content-Type` 头（例如 `application/json`），其请求体才会被按 JSON 解析。

## CSRF 风险 { #csrf-risk }

此默认行为在一个非常特定的场景下，可防御一类跨站请求伪造（CSRF）攻击。

这类攻击利用了浏览器的一个事实：当请求满足以下条件时，浏览器允许脚本在不进行任何 CORS 预检的情况下直接发送请求：

- 没有 `Content-Type` 头（例如使用 `fetch()` 携带 `Blob` 作为 body）
- 且不发送任何认证凭据。

这种攻击主要在以下情况下相关：

- 应用在本地（如 `localhost`）或内网中运行

### Create Database Tables on Startup { #create-database-tables-on-startup }

We will create the database tables when the application starts.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[32:37] hl[35:37] *}

Here we create the tables on an application startup event.

For production you would probably use a migration script that runs before you start your app. 🤓

/// tip

> NOTE: Server side replication is supported for idempotent versions on directory objects.

### Idempotent versions on delete markers

Duplicate delete markers are not created on MinIO buckets with versioning, if an application performs a soft delete on an object repeatedly - that object will only ever have a single DELETE marker for all such successive attempts. This is done to ensure that repeated soft deletes do not ever need multiple versions in the first place.

        // Force probes to be loaded
        ProcessProbe.getInstance();
        OsProbe.getInstance();
        JvmInfo.jvmInfo();
    }

    /**
     * Main entry point for the thumbnail generator application.
     *
     * @param args command-line arguments
     */
    public static void main(final String[] args) {
        final Options options = new Options();