```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

### 在 FastAPI 应用里设置 `root_path`

还有一种方案，如果不能提供 `--root-path` 或等效的命令行选项，则在创建 FastAPI 应用时要设置 `root_path` 参数。

```Python hl_lines="3"
{!../../../docs_src/behind_a_proxy/tutorial002.py!}
```

传递 `root_path` 给 `FastAPI` 与传递 `--root-path` 命令行选项给 Uvicorn 或 Hypercorn 一样。

### 关于 `root_path`

注意，服务器（Uvicorn）只是把 `root_path` 传递给应用。

         * which to start, and using expressions split at the dot ('.') to navigate
         * the object graph beneath this root.
         * @param root the root of the graph.
         */
        public ObjectBasedValueSource(Object root) {
            super(true);
            this.root = root;
        }

        /**

        .addHeader("Cookie: s=square")
        .addHeader("Cookie: a=android")
        .addHeader("Cookies: delicious")
    response.setHeader("cookie", "r=robot")
    assertThat(headersToList(response))
      .containsExactly("Cookies: delicious", "cookie: r=robot")
  }

  @Test
  fun mockResponseSetHeaders() {
    val response =
      MockResponse()
        .clearHeaders()

	)

	ErrMissingEnvCredentialAccessKey = newErrFn(
		"Missing credential environment variable, \""+EnvAccessKey+"\"",
		"Environment variables \""+EnvAccessKey+"\" and \""+EnvSecretKey+"\" are deprecated",
		`Root user name (access key) and root password (secret key) are expected to be specified via environment variables MINIO_ROOT_USER and MINIO_ROOT_PASSWORD respectively`,
	)

                "post": {
                    "summary": "Post Root",
                    "operationId": "foo_post_root",
                    "requestBody": {
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/Body_foo_post_root"
                                }
                            }

        DependencyCoordinate root;
        Collection<DependencyCoordinate> dependencies;
        Collection<DependencyCoordinate> managedDependencies;
        List<RemoteRepository> remoteRepositories;
        if (request.getProject().isPresent()) {
            Project project = request.getProject().get();
            rootArtifact = project.getPomArtifact();
            root = null;

	root := d.find(path)
	if root == nil || len(root.Children) == 0 {
		return root
	}
	flat := d.flatten(*root)
	if flat.ReplicationStats.empty() {
		flat.ReplicationStats = nil
	}
	return &flat
}

// totalChildrenRec returns the total number of children recorded.
func (d *dataUsageCache) totalChildrenRec(path string) int {
	root := d.find(path)

        DependencyCoordinate root;
        Collection<DependencyCoordinate> dependencies;
        Collection<DependencyCoordinate> managedDependencies;
        List<RemoteRepository> remoteRepositories;
        if (request.getProject().isPresent()) {
            Project project = request.getProject().get();
            rootArtifact = project.getPomArtifact();
            root = null;

from fastapi import FastAPI, Request

app = FastAPI(root_path="/api/v1")


@app.get("/app")
def read_main(request: Request):

  }

  public void testCreateParentDirectories_root() throws IOException {
    // We use a fake filesystem to sidestep flaky problems with Windows (b/136041958).
    try (FileSystem fs = Jimfs.newFileSystem(Configuration.unix())) {
      Path root = fs.getRootDirectories().iterator().next();
      assertNull(root.getParent());
      assertNull(root.toRealPath().getParent());