## **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.

#       command line, like:
#
#           ksh Gradle
#
#       Busybox and similar reduced shells will NOT work, because this script
#       requires all of these POSIX shell features:
#         * functions;
#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;

## GitHub docs: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
##
## CODEOWNERS style rules:
## 1. Prefer team ownership over individual user ownership.
## 2. GBT-related team should be listed first.
## 3. Try to keep paths alphabetically sorted within visual groups.
## 4. List individual owners last.
##

# Build infrastructure

    the OkHttp version in custom `User-Agent` headers.

 *  Fix: Don't crash when running as a plugin in Android Studio Canary 4.1. To enable
    platform-specific TLS features OkHttp must detect whether it's running in a JVM or in Android.
    The upcoming Android Studio runs in a JVM but has classes from Android and that confused OkHttp!

Feature requests
----------------

If you find yourself wishing for a feature that doesn't exist in Elasticsearch, you are probably not alone. There are bound to be others out there with similar needs. Many of the features that Elasticsearch has today have been added because our users saw the need.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.smb.SmbException;

/**
 * Rate limiter for authentication attempts to prevent brute force attacks.
 *
 * Features:
 * - Per-account rate limiting
 * - Per-IP rate limiting
 * - Global rate limiting
 * - Exponential backoff for repeated failures
 * - Account lockout after threshold
 * - Automatic cleanup of old entries
 */

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.smb.SmbException;

/**
 * Path validation utility to prevent directory traversal and other path-based attacks.
 *
 * Features:
 * - Directory traversal prevention
 * - Path normalization
 * - Blacklist/whitelist support
 * - UNC path validation
 * - Special character filtering
 * - Length validation
 */
public class PathValidator {

/**
 * Secure credential storage with encryption at rest.
 *
 * Provides secure storage of passwords and other sensitive credentials
 * using AES-GCM encryption with PBKDF2 key derivation.
 *
 * Features:
 * - Encrypts credentials at rest using AES-256-GCM
 * - Uses PBKDF2 for key derivation from master password
 * - Secure wiping of sensitive data
 * - Thread-safe operations
 * - Protection against timing attacks
 */

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Centralized resource management for preventing resource leaks.
 * Tracks all AutoCloseable resources and ensures proper cleanup.
 *
 * Features:
 * - Automatic resource cleanup with weak references
 * - Resource leak detection
 * - Resource usage monitoring
 * - Periodic cleanup of abandoned resources
 * - Detailed resource tracking and reporting
 */

> NOTE: Server side replication is supported for idempotent versions on delete marked objects.

### Motivation