Alternatively, if you don't have a way to provide a command line option like `--root-path` or equivalent, you can set the `root_path` parameter when creating your FastAPI app:

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

Passing the `root_path` to `FastAPI` would be the equivalent of passing the `--root-path` command line option to Uvicorn or Hypercorn.

### About `root_path`

<font color="#4E9A06">INFO</font>:     Application startup complete.
```

</div>

In the output, there's a line with something like:

```hl_lines="4"
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

That line shows the URL where your app is being served, in your local machine.

### Check it

        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", 1],
                    "msg": "Expecting property name enclosed in double quotes: line 1 column 2 (char 1)",
                    "type": "value_error.jsondecode",
                    "ctx": {
                        "msg": "Expecting property name enclosed in double quotes",

        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", 1],
                    "msg": "Expecting property name enclosed in double quotes: line 1 column 2 (char 1)",
                    "type": "value_error.jsondecode",
                    "ctx": {
                        "msg": "Expecting property name enclosed in double quotes",

<div class="termy">

```console
$ npm install @hey-api/openapi-ts --save-dev

---> 100%
```

</div>

#### Generate Client Code

To generate the client code you can use the command line application `openapi-ts` that would now be installed.

Because it is installed in the local project, you probably wouldn't be able to call that command directly, but you would put it on your `package.json` file.

And there are extra tools/scripts in place to handle translations in `./scripts/docs.py`.

!!! tip
    You don't need to see the code in `./scripts/docs.py`, you just use it in the command line.

All the documentation is in Markdown format in the directory `./docs/en/`.

Many of the tutorials have blocks of code.

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

Se stai sviluppando un'app <abbr title="Command Line Interface (interfaccia della riga di comando)">CLI</abbr> da usare nel terminale invece che una web API, ti consigliamo <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>.

## **Typer**，命令行中的 FastAPI

<a href="https://typer.tiangolo.com" target="_blank"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" style="width: 20%;"></a>

如果你正在开发一个在终端中运行的<abbr title="Command Line Interface">命令行</abbr>应用而不是 web API，不妨试下 <a href="https://typer.tiangolo.com/" class="external-link" target="_blank">**Typer**</a>。

**Typer** 是 FastAPI 的小同胞。它想要成为**命令行中的 FastAPI**。 ⌨️ 🚀

## 依赖

Python 及更高版本

👆 💪 ✍ 🌐 🔢 🕴 🎯 📋 👼, 👈 🕴 💪 👈 📋, & 🕴 🚮 📐.

👈, ✍ ⚫️ ▶️️ ⏭ 📋 ⚫️, 🔛 🎏 ⏸:

<div class="termy">

```console
// Create an env var MY_NAME in line for this program call
$ MY_NAME="Wade Wilson" python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python

// The env var no longer exists afterwards
$ python main.py

```

!!! tip
    There are several `__init__.py` files: one in each directory or subdirectory.

    This is what allows importing code from one file into another.

    For example, in `app/main.py` you could have a line like:

    ```
    from app.routers import items
    ```

* The `app` directory contains everything. And it has an empty file `app/__init__.py`, so it is a "Python package" (a collection of "Python modules"): `app`.