## **FastAPI**'s `OAuth2PasswordBearer` { #fastapis-oauth2passwordbearer }

**FastAPI** provides several tools, at different levels of abstraction, to implement these security features.

In this example we are going to use **OAuth2**, with the **Password** flow, using a **Bearer** token. We do that using the `OAuth2PasswordBearer` class.

/// info

A "bearer" token is not the only option.

But it's the best one for our use case.

		}
		if diskIndex != 0 && disk == nil {
			t.Errorf("Drive erroneously filtered, driveIndex: %d", diskIndex)
		}
	}
	partsMetadata[0] = partsMetadataBackup // Revert before going to the next test

	// Test 3: Not synchronized DataDir
	erasureDisks = s.getDisks()
	partsMetadataBackup = partsMetadata[1]
	partsMetadata[1].DataDir = "foo-random"

	errs = make([]error, len(erasureDisks))

The `security_scopes` object (of class `SecurityScopes`) also provides a `scope_str` attribute with a single string, containing those scopes separated by spaces (we are going to use it).

We create an `HTTPException` that we can reuse (`raise`) later at several points.

	SkipRebalancing bool

	SrcPoolIdx int // set by PutObject/CompleteMultipart operations due to rebalance; used to prevent rebalance src, dst pools to be the same

	DataMovement bool // indicates an going decommisionning or rebalacing

	PrefixEnabledFn func(prefix string) bool // function which returns true if versioning is enabled on prefix

	// IndexCB will return any index created but the compression.

 */
@GwtCompatible
@NullMarked
public class UnmodifiableCollectionTests {

  public static void assertMapEntryIsUnmodifiable(Entry<?, ?> entry) {
    try {
      // fine because the call is going to fail without modifying the entry
      @SuppressWarnings("unchecked")
      Entry<?, @Nullable Object> nullableValueEntry = (Entry<?, @Nullable Object>) entry;
      nullableValueEntry.setValue(null);

                : new NonTerminalImmutableMapEntry<K, V>(key, value, keyBucketHead);
        table[tableIndex] = effectiveEntry;
      } else {
        // We already saw this key, and the first value we saw (going backwards) is the one we are
        // keeping. So we won't touch table[], but we do still want to add the existing entry that
        // we found to entries[] so that we will see this key in the right place when iterating.

You use `which` in Linux and macOS and `Get-Command` in Windows PowerShell.

The way that command works is that it will go and check in the `PATH` environment variable, going through **each path in order**, looking for the program called `python`. Once it finds it, it will **show you the path** to that program.

        .Builder()
        .webSocketUpgrade(serverListener)
        .build(),
    )
    val webSocket: WebSocket = newWebSocket()
    clientListener.assertOpen()

    // Send messages until the client's outgoing buffer overflows!
    val message: ByteString = ByteString.of(*ByteArray(1024 * 1024))
    var messageCount: Long = 0
    while (true) {
      val success = webSocket.send(message)
      if (!success) break

This code is something you can actually use in your application, save the password hashes in your database, etc.

We are going to start from where we left in the previous chapter and increment it.

## About JWT { #about-jwt }

JWT means "JSON Web Tokens".

Having `str | None` will allow your editor to give you better support and detect errors.

///

## Additional validation { #additional-validation }

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated` { #import-query-and-annotated }

To achieve that, first import: