from fastapi import FastAPI, Security
from fastapi.security import OAuth2AuthorizationCodeBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize", tokenUrl="token", auto_error=True
)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    return {"token": token}


client = TestClient(app)

import logging
import urllib
from uuid import uuid4

import boto3
import requests
from botocore.client import Config
from flask import Flask, request

boto3.set_stream_logger('boto3.resources', logging.DEBUG)

authorize_url = "http://localhost:8080/auth/realms/minio/protocol/openid-connect/auth"
token_url = "http://localhost:8080/auth/realms/minio/protocol/openid-connect/token"

# callback url specified when the application was defined

from fastapi import FastAPI, Security
from fastapi.security import OAuth2AuthorizationCodeBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize",
    tokenUrl="token",
    description="OAuth2 Code Bearer",
    auto_error=True,
)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    return {"token": token}

  }

  /** See https://api.slack.com/docs/oauth. */
  public HttpUrl authorizeUrl(String scopes, HttpUrl redirectUrl, ByteString state, String team) {
    HttpUrl.Builder builder = baseUrl.newBuilder("/oauth/authorize")
        .addQueryParameter("client_id", clientId)
        .addQueryParameter("scope", scopes)
        .addQueryParameter("redirect_uri", redirectUrl.toString())
        .addQueryParameter("state", state.base64());

	size := 0
	// Figure out the data block length.
	for _, block := range enBlocks[:dataBlocks] {
		size += len(block)
	}
	return size
}

// Writes all the data blocks from encoded blocks until requested
// outSize length. Provides a way to skip bytes until the offset.
func writeDataBlocks(ctx context.Context, dst io.Writer, enBlocks [][]byte, dataBlocks int, offset int64, length int64) (int64, error) {
	// Offset and out size cannot be negative.

界面如下图所示：

<img src="/img/tutorial/security/image01.png">

!!! check "Authorize 按钮！"

    页面右上角出现了一个「**Authorize**」按钮。

    *路径操作*的右上角也出现了一个可以点击的小锁图标。

点击 **Authorize** 按钮，弹出授权表单，输入 `username` 与 `password` 及其它可选字段：

<img src="/img/tutorial/security/image02.png">

!!! note "笔记"

    目前，在表单中输入内容不会有任何反应，后文会介绍相关内容。

You will see something like this:

<img src="/img/tutorial/security/image01.png">

!!! check "Authorize button!"
    You already have a shiny new "Authorize" button.

    And your *path operation* has a little lock in the top-right corner that you can click.

OPA is a lightweight general-purpose policy engine that can be co-located with MinIO server, in this document we talk about how to use OPA HTTP API to authorize requests. It can be used with any type of credentials (STS based like OpenID or LDAP, regular IAM users or service accounts).

OPA is enabled through MinIO's Access Management Plugin feature.

## Get started

  /** Guarded by this. */
  private OAuthSession session;

  public SlackClient(SlackApi slackApi) {
    this.slackApi = slackApi;
  }

  /** Shows a browser URL to authorize this app to act as this user. */
  public void requestOauthSession(String scopes, String team) throws Exception {
    if (sessionFactory == null) {
      sessionFactory = new OAuthSessionFactory(slackApi);

    try {
      getList().listIterator(getNumElements() + 1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
  }

  public void testListIterator_atSize() {
    getList().listIterator(getNumElements());
    // TODO: run the iterator through ListIteratorTester
  }

  /**
   * Returns the {@link Method} instance for {@link #testListIterator_fullyModifiable()} so that