## OAuth2

OAuth2 is a specification that defines several ways to handle authentication and authorization.

It is quite an extensive specification and covers several complex use cases.

It includes ways to authenticate using a "third party".

That's what all the systems with "login with Facebook, Google, Twitter, GitHub" use underneath.

<font color="#4E9A06">INFO</font>:     Will watch for changes in these directories: [&apos;/home/user/code/awesomeapp&apos;]
<font color="#4E9A06">INFO</font>:     Uvicorn running on <b>http://127.0.0.1:8000</b> (Press CTRL+C to quit)
<font color="#4E9A06">INFO</font>:     Started reloader process [<font color="#34E2E2"><b>2265862</b></font>] using <font color="#34E2E2"><b>WatchFiles</b></font>

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

صفحه مستندات را در آدرس <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a> باز کنید.

 * </pre>
 * 
 * the access check would fail because the direct ACE has an access mask
 * of <tt>0x001200A9</tt> which doesn't have the
 * <tt>FILE_WRITE_DATA</tt> bit on (bit <tt>0x00000002</tt>). Actually, this isn't quite correct. If
 * <tt>WNET\alice</tt> is in the local <tt>Administrators</tt> group the access check
 * will succeed because the inherited ACE allows local <tt>Administrators</tt>

<div class="termy">

```console
$ fastapi run main.py --root-path /api/v1

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

If you use Hypercorn, it also has the option `--root-path`.

/// note | "Technical Details"

The ASGI specification defines a `root_path` for this use case.

<div class="termy">

```console
$ OPENAPI_URL= uvicorn main:app

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

⤴️ 🚥 👆 🚶 📛 `/openapi.json`, `/docs`, ⚖️ `/redoc` 👆 🔜 🤚 `404 Not Found` ❌ 💖:

```JSON
{
    "detail": "Not Found"
}

🏃 🙆 🖼, 📁 📟 📁 `main.py`, & ▶️ `uvicorn` ⏮️:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]
<span style="color: green;">INFO</span>:     Waiting for application startup.

 <font color="#4E9A06">╰─────────────────────────────────────────────────────╯</font>

<font color="#4E9A06">INFO</font>:     Uvicorn running on <b>http://0.0.0.0:8000</b> (Press CTRL+C to quit)
<font color="#4E9A06">INFO</font>:     Started parent process [<font color="#34E2E2"><b>27365</b></font>]
<font color="#4E9A06">INFO</font>:     Started server process [<font color="#06989A">27368</font>]

<div class="termy">

```console
$ OPENAPI_URL= uvicorn main:app

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

Then if you go to the URLs at `/openapi.json`, `/docs`, or `/redoc` you will just get a `404 Not Found` error like:

```JSON
{
    "detail": "Not Found"
}

# This env is only valid when RBE is available on the selected platform, since
# it enables a derived --config setting.  If RBE is not available (i.e. there
# is no --config setting), bazel would fail and quit. This script does a quick
# check This script checks for such errors early
if ! grep "rbe_$TFCI_BAZEL_TARGET_SELECTING_CONFIG_PREFIX" .bazelrc; then
  cat <<EOF
ERROR: RBE was enabled via the 'rbe' env in the 'TFCI' variable.