本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# 使用 AWS SDK AWS STS 為聯合身分使用者使用 建構 URL
<a name="sts_example_sts_Scenario_ConstructFederatedUrl_section"></a>

以下程式碼範例顯示做法：
+ 建立可對目前帳戶的 Amazon S3 資源授予唯讀存取權的 IAM 角色。
+ 從 AWS 聯合端點取得安全字符。
+ 建構可用來使用聯合憑證存取主控台的 URL。

------
#### [ Python ]

**適用於 Python 的 SDK (Boto3)**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/sts#code-examples)中設定和執行。
建立可對目前帳戶的 S3 資源授予唯讀存取權的角色。  

```
def setup(iam_resource):
    """
    Creates a role that can be assumed by the current user.
    Attaches a policy that allows only Amazon S3 read-only access.

    :param iam_resource: A Boto3 AWS Identity and Access Management (IAM) instance
                         that has the permission to create a role.
    :return: The newly created role.
    """
    role = iam_resource.create_role(
        RoleName=unique_name("role"),
        AssumeRolePolicyDocument=json.dumps(
            {
                "Version":"2012-10-17",		 	 	 
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Principal": {"AWS": iam_resource.CurrentUser().arn},
                        "Action": "sts:AssumeRole",
                    }
                ],
            }
        ),
    )
    role.attach_policy(PolicyArn="arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess")
    print(f"Created role {role.name}.")

    print("Give AWS time to propagate these new resources and connections.", end="")
    progress_bar(10)

    return role
```
從 AWS 聯合端點取得安全字符，並建構可用於使用聯合憑證存取主控台的 URL。  

```
def construct_federated_url(assume_role_arn, session_name, issuer, sts_client):
    """
    Constructs a URL that gives federated users direct access to the AWS Management
    Console.

    1. Acquires temporary credentials from AWS Security Token Service (AWS STS) that
       can be used to assume a role with limited permissions.
    2. Uses the temporary credentials to request a sign-in token from the
       AWS federation endpoint.
    3. Builds a URL that can be used in a browser to navigate to the AWS federation
       endpoint, includes the sign-in token for authentication, and redirects to
       the AWS Management Console with permissions defined by the role that was
       specified in step 1.

    :param assume_role_arn: The role that specifies the permissions that are granted.
                            The current user must have permission to assume the role.
    :param session_name: The name for the STS session.
    :param issuer: The organization that issues the URL.
    :param sts_client: A Boto3 STS instance that can assume the role.
    :return: The federated URL.
    """
    response = sts_client.assume_role(
        RoleArn=assume_role_arn, RoleSessionName=session_name
    )
    temp_credentials = response["Credentials"]
    print(f"Assumed role {assume_role_arn} and got temporary credentials.")

    session_data = {
        "sessionId": temp_credentials["AccessKeyId"],
        "sessionKey": temp_credentials["SecretAccessKey"],
        "sessionToken": temp_credentials["SessionToken"],
    }
    aws_federated_signin_endpoint = "https://signin.aws.amazon.com/federation"

    # Make a request to the AWS federation endpoint to get a sign-in token.
    # The requests.get function URL-encodes the parameters and builds the query string
    # before making the request.
    response = requests.get(
        aws_federated_signin_endpoint,
        params={
            "Action": "getSigninToken",
            "SessionDuration": str(datetime.timedelta(hours=12).seconds),
            "Session": json.dumps(session_data),
        },
    )
    signin_token = json.loads(response.text)
    print(f"Got a sign-in token from the AWS sign-in federation endpoint.")

    # Make a federated URL that can be used to sign into the AWS Management Console.
    query_string = urllib.parse.urlencode(
        {
            "Action": "login",
            "Issuer": issuer,
            "Destination": "https://console.aws.amazon.com/",
            "SigninToken": signin_token["SigninToken"],
        }
    )
    federated_url = f"{aws_federated_signin_endpoint}?{query_string}"
    return federated_url
```
銷毀為示範所建立的資源。  

```
def teardown(role):
    """
    Removes all resources created during setup.

    :param role: The demo role.
    """
    for attached in role.attached_policies.all():
        role.detach_policy(PolicyArn=attached.arn)
        print(f"Detached {attached.policy_name}.")
    role.delete()
    print(f"Deleted {role.name}.")
```
使用先前定義的函數執行此案例。  

```
def usage_demo():
    """Drives the demonstration."""
    print("-" * 88)
    print(f"Welcome to the AWS Security Token Service federated URL demo.")
    print("-" * 88)
    iam_resource = boto3.resource("iam")
    role = setup(iam_resource)
    sts_client = boto3.client("sts")
    try:
        federated_url = construct_federated_url(
            role.arn, "AssumeRoleDemoSession", "example.org", sts_client
        )
        print(
            "Constructed a federated URL that can be used to connect to the "
            "AWS Management Console with role-defined permissions:"
        )
        print("-" * 88)
        print(federated_url)
        print("-" * 88)
        _ = input(
            "Copy and paste the above URL into a browser to open the AWS "
            "Management Console with limited permissions. When done, press "
            "Enter to clean up and complete this demo."
        )
    finally:
        teardown(role)
        print("Thanks for watching!")
```
+  如需 API 詳細資訊，請參閱 *AWS SDK for Python (Boto3) API Reference* 中的 [AssumeRole](https://docs.aws.amazon.com/goto/boto3/sts-2011-06-15/AssumeRole)。

------

如需 AWS SDK 開發人員指南和程式碼範例的完整清單，請參閱 [搭配 AWS SDK 使用此服務](sdk-general-information-section.md)。此主題也包含有關入門的資訊和舊版 SDK 的詳細資訊。