assumeRoleWithWebIdentity method

Future<AssumeRoleWithWebIdentityResponse> assumeRoleWithWebIdentity({ required String roleArn, required String roleSessionName, required String webIdentityToken, int? durationSeconds, String? policy, List<PolicyDescriptorType>? policyArns, String? providerId, })

Returns a set of temporary security credentials for users who have been authenticated in a mobile or web application with a web identity provider. Example providers include the OAuth 2.0 providers Login with Amazon and Facebook, or any OpenID Connect-compatible identity provider such as Google or Amazon Cognito federated identities.

To learn more about Amazon Cognito, see Amazon Cognito identity pools in Amazon Cognito Developer Guide. Calling AssumeRoleWithWebIdentity does not require the use of Amazon Web Services security credentials. Therefore, you can distribute an application (for example, on mobile devices) that requests temporary security credentials without including long-term Amazon Web Services credentials in the application. You also don't need to deploy server-based proxy services that use long-term Amazon Web Services credentials. Instead, the identity of the caller is validated by using a token from the web identity provider. For a comparison of AssumeRoleWithWebIdentity with the other API operations that produce temporary credentials, see Requesting Temporary Security Credentials and Compare STS credentials in the IAM User Guide.

The temporary security credentials returned by this API consist of an access key ID, a secret access key, and a security token. Applications can use these temporary security credentials to sign calls to Amazon Web Services service API operations.

Session Duration

By default, the temporary security credentials created by AssumeRoleWithWebIdentity last for one hour. However, you can use the optional DurationSeconds parameter to specify the duration of your session. You can provide a value from 900 seconds (15 minutes) up to the maximum session duration setting for the role. This setting can have a value from 1 hour to 12 hours. To learn how to view the maximum value for your role, see Update the maximum session duration for a role in the IAM User Guide. The maximum session duration limit applies when you use the AssumeRole* API operations or the assume-role* CLI commands. However the limit does not apply when you use those operations to create a console URL. For more information, see Using IAM Roles in the IAM User Guide.

Permissions

The temporary security credentials created by AssumeRoleWithWebIdentity can be used to make API calls to any Amazon Web Services service with the following exception: you cannot call the STS GetFederationToken or GetSessionToken API operations.

(Optional) You can pass inline or managed session policies to this operation. You can pass a single JSON policy document to use as an inline session policy. You can also specify up to 10 managed policy Amazon Resource Names (ARNs) to use as managed session policies. The plaintext that you use for both inline and managed session policies can't exceed 2,048 characters. Passing policies to this operation returns new temporary credentials. The resulting session's permissions are the intersection of the role's identity-based policy and the session policies. You can use the role's temporary credentials in subsequent Amazon Web Services API calls to access resources in the account that owns the role. You cannot use session policies to grant more permissions than those allowed by the identity-based policy of the role that is being assumed. For more information, see Session Policies in the IAM User Guide.

Tags

(Optional) You can configure your IdP to pass attributes into your web identity token as session tags. Each session tag consists of a key name and an associated value. For more information about session tags, see Passing session tags using AssumeRoleWithWebIdentity in the IAM User Guide.

You can pass up to 50 session tags. The plaintext session tag keys can’t exceed 128 characters and the values can’t exceed 256 characters. For these and additional limits, see IAM and STS Character Limits in the IAM User Guide. You can pass a session tag with the same key as a tag that is attached to the role. When you do, the session tag overrides the role tag with the same key.

An administrator must grant you the permissions necessary to pass session tags. The administrator can also create granular permissions to allow you to pass only specific session tags. For more information, see Tutorial: Using Tags for Attribute-Based Access Control in the IAM User Guide.

You can set the session tags as transitive. Transitive tags persist during role chaining. For more information, see Chaining Roles with Session Tags in the IAM User Guide.

Identities

Before your application can call AssumeRoleWithWebIdentity, you must have an identity token from a supported identity provider and create a role that the application can assume. The role that your application assumes must trust the identity provider that is associated with the identity token. In other words, the identity provider must be specified in the role's trust policy. For more information about how to use OIDC federation and the AssumeRoleWithWebIdentity API, see the following resources:

• Using Web Identity Federation API Operations for Mobile Apps and Federation Through a Web-based Identity Provider.
• Amazon Web Services SDK for iOS Developer Guide and Amazon Web Services SDK for Android Developer Guide. These toolkits contain sample apps that show how to invoke the identity providers. The toolkits then show how to use the information from these providers to get and use temporary security credentials.

May throw ExpiredTokenException. May throw IDPCommunicationErrorException. May throw IDPRejectedClaimException. May throw InvalidIdentityTokenException. May throw MalformedPolicyDocumentException. May throw PackedPolicyTooLargeException. May throw RegionDisabledException.

Parameter roleArn : The Amazon Resource Name (ARN) of the role that the caller is assuming.

Parameter roleSessionName : An identifier for the assumed role session. Typically, you pass the name or identifier that is associated with the user who is using your application. That way, the temporary security credentials that your application will use are associated with that user. This session name is included as part of the ARN and assumed role ID in the AssumedRoleUser response element.

For security purposes, administrators can view this field in CloudTrail logs to help identify who performed an action in Amazon Web Services. Your administrator might require that you specify your user name as the session name when you assume the role. For more information, see sts:RoleSessionName .

The regex used to validate this parameter is a string of characters consisting of upper- and lower-case alphanumeric characters with no spaces. You can also include underscores or any of the following characters: =,.@-

Parameter webIdentityToken : The OAuth 2.0 access token or OpenID Connect ID token that is provided by the identity provider. Your application must get this token by authenticating the user who is using your application with a web identity provider before the application makes an AssumeRoleWithWebIdentity call. Timestamps in the token must be formatted as either an integer or a long integer. Tokens must be signed using either RSA keys (RS256, RS384, or RS512) or ECDSA keys (ES256, ES384, or ES512).

Parameter durationSeconds : The duration, in seconds, of the role session. The value can range from 900 seconds (15 minutes) up to the maximum session duration setting for the role. This setting can have a value from 1 hour to 12 hours. If you specify a value higher than this setting, the operation fails. For example, if you specify a session duration of 12 hours, but your administrator set the maximum session duration to 6 hours, your operation fails. To learn how to view the maximum value for your role, see View the Maximum Session Duration Setting for a Role in the IAM User Guide.

By default, the value is set to 3600 seconds.

Parameter policy : An IAM policy in JSON format that you want to use as an inline session policy.

This parameter is optional. Passing policies to this operation returns new temporary credentials. The resulting session's permissions are the intersection of the role's identity-based policy and the session policies. You can use the role's temporary credentials in subsequent Amazon Web Services API calls to access resources in the account that owns the role. You cannot use session policies to grant more permissions than those allowed by the identity-based policy of the role that is being assumed. For more information, see Session Policies in the IAM User Guide.

The plaintext that you use for both inline and managed session policies can't exceed 2,048 characters. The JSON policy characters can be any ASCII character from the space character to the end of the valid character list (\u0020 through \u00FF). It can also include the tab (\u0009), linefeed (\u000A), and carriage return (\u000D) characters.

For more information about role session permissions, see Session policies.

Parameter policyArns : The Amazon Resource Names (ARNs) of the IAM managed policies that you want to use as managed session policies. The policies must exist in the same account as the role.

This parameter is optional. You can provide up to 10 managed policy ARNs. However, the plaintext that you use for both inline and managed session policies can't exceed 2,048 characters. For more information about ARNs, see Amazon Resource Names (ARNs) and Amazon Web Services Service Namespaces in the Amazon Web Services General Reference. Passing policies to this operation returns new temporary credentials. The resulting session's permissions are the intersection of the role's identity-based policy and the session policies. You can use the role's temporary credentials in subsequent Amazon Web Services API calls to access resources in the account that owns the role. You cannot use session policies to grant more permissions than those allowed by the identity-based policy of the role that is being assumed. For more information, see Session Policies in the IAM User Guide.

Parameter providerId : The fully qualified host component of the domain name of the OAuth 2.0 identity provider. Do not specify this value for an OpenID Connect identity provider.

Currently www.amazon.com and graph.facebook.com are the only supported identity providers for OAuth 2.0 access tokens. Do not include URL schemes and port numbers.

Do not specify this value for OpenID Connect ID tokens.

Implementation

Future<AssumeRoleWithWebIdentityResponse> assumeRoleWithWebIdentity({
  required String roleArn,
  required String roleSessionName,
  required String webIdentityToken,
  int? durationSeconds,
  String? policy,
  List<PolicyDescriptorType>? policyArns,
  String? providerId,
}) async {
  _s.validateNumRange(
    'durationSeconds',
    durationSeconds,
    900,
    43200,
  );
  final $request = <String, String>{
    'RoleArn': roleArn,
    'RoleSessionName': roleSessionName,
    'WebIdentityToken': webIdentityToken,
    if (durationSeconds != null)
      'DurationSeconds': durationSeconds.toString(),
    if (policy != null) 'Policy': policy,
    if (policyArns != null)
      if (policyArns.isEmpty)
        'PolicyArns': ''
      else
        for (var i1 = 0; i1 < policyArns.length; i1++)
          for (var e3 in policyArns[i1].toQueryMap().entries)
            'PolicyArns.member.${i1 + 1}.${e3.key}': e3.value,
    if (providerId != null) 'ProviderId': providerId,
  };
  final $result = await _protocol.send(
    $request,
    action: 'AssumeRoleWithWebIdentity',
    version: '2011-06-15',
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    signed: false,
    resultWrapper: 'AssumeRoleWithWebIdentityResult',
  );
  return AssumeRoleWithWebIdentityResponse.fromXml($result);
}