{* ../../docs_src/behind_a_proxy/tutorial002.py hl[3] *}

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`

Keep in mind that the server (Uvicorn) won't use that `root_path` for anything else than passing it to the app.

user_dict = user_in.dict()
UserInDB(**user_dict)
```

would be equivalent to:

```Python
UserInDB(**user_in.dict())
```

...because `user_in.dict()` is a `dict`, and then we make Python "unwrap" it by passing it to `UserInDB` prefixed with `**`.

So, we get a Pydantic model from the data in another Pydantic model.

#### Unwrapping a `dict` and extra keywords

For those cases, you can use the `jsonable_encoder` to convert your data before passing it to a response:

```Python hl_lines="6-7  21-22"
{!../../docs_src/response_directly/tutorial001.py!}
```

/// note | "Technical Details"

You could also use `from starlette.responses import JSONResponse`.

The vendor directory may be updated with 'go mod vendor'.
A typical sequence might be:

    cd src  # or src/cmd
    go get golang.org/x/net@master
    go mod tidy
    go mod vendor

Use caution when passing '-u' to 'go get'. The '-u' flag updates
modules providing all transitively imported packages, not only
the module providing the target package.

Note that 'go mod vendor' only copies packages that are transitively

///

The only thing the function returned by `GzipRequest.get_route_handler` does differently is convert the `Request` to a `GzipRequest`.

Doing this, our `GzipRequest` will take care of decompressing the data (if necessary) before passing it to our *path operations*.

After that, all of the processing logic is the same.

Check how deprecated and non-deprecated *path operations* look like:

<img src="/img/tutorial/path-operation-configuration/image05.png">

## Recap

current implementation may sometimes cause a runtime error if the
contents of the C memory appear to be a Go pointer. Therefore, avoid
passing uninitialized C memory to Go code if the Go code is going to
store pointer values in it. Zero out the memory in C before passing it
to Go.

# Optimizing calls of C code

When passing a Go pointer to a C function the compiler normally ensures
that the Go object lives on the heap. If the C function does not keep

    private List<String> defaultIds = new ArrayList<>();

    private Map<String, Profile> profilesById = new LinkedHashMap<>();

    private Properties requestProperties;

    /**
     * @deprecated without passing in the system properties, the SystemPropertiesProfileActivator will not work
     *             correctly in embedded environments.
     */
    @Deprecated
    public DefaultProfileManager(PlexusContainer container) {

But if you are certain that the content that you are returning is **serializable with JSON**, you can pass it directly to the response class and avoid the extra overhead that FastAPI would have by passing your return content through the `jsonable_encoder` before passing it to the response class.

```Python hl_lines="2  7"
{!../../docs_src/custom_response/tutorial001b.py!}
```

/// info

```console
$ pip install httpx
```

///

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.