AWS Amplify Auth登录会话应用重启后无法持久化的原因？

我的Amplify配置代码 #

do {
    Amplify.Logging.logLevel = .verbose
    try Amplify.add(plugin: AWSCognitoAuthPlugin())
    try Amplify.add(plugin: AWSS3StoragePlugin())
    try Amplify.add(plugin: apiPlugin)
    try Amplify.configure()
    print("Initialized Amplify")
} catch {
    print("Could not initialize Amplify: \(error)")
}

登录状态检查代码 #

do {
    let session = try await Amplify.Auth.fetchAuthSession()
    switch session.isSignedIn {
    case true:
        DZLog("Signed in")
    case false:
        DZLog("Not signed in")
    }
} catch {
    DZError("Error while fetching session", error: error)
}

登录实现代码 #

do {
    let options = AuthWebUISignInRequest.Options(scopes: ["openid", "email", "profile", "aws.cognito.signin.user.admin"], pluginOptions: AuthWebUISignInRequest.Options.preferPrivateSession())
    let signInResult = try await Amplify.Auth.signInWithWebUI(for: .apple, presentationAnchor: window, options: options)
    if signInResult.isSignedIn {
        print("Sign in succeeded")
    }
} catch let error as AuthError {
    DZError("Error in signin", error:error)
} catch {
    DZError("Error in signin", error:error)
}

问题描述 #

应用重启后，调用Amplify.Auth.fetchAuthSession()始终返回未登录状态，登录会话无法在重启间保持持久化。

原因 #

你在登录时使用了AuthWebUISignInRequest.Options.preferPrivateSession()插件选项。该选项会让Web UI登录流程使用私有浏览器会话，而私有会话的设计逻辑就是不持久化存储用户凭证——会话结束（如关闭浏览器、重启应用）后，凭证会被自动清除，导致应用重启后无法恢复登录状态。

解决方案 #

移除preferPrivateSession()这个插件选项，修改后的登录代码如下：

do {
    let options = AuthWebUISignInRequest.Options(scopes: ["openid", "email", "profile", "aws.cognito.signin.user.admin"])
    let signInResult = try await Amplify.Auth.signInWithWebUI(for: .apple, presentationAnchor: window, options: options)
    if signInResult.isSignedIn {
        print("Sign in succeeded")
    }
} catch let error as AuthError {
    DZError("Error in signin", error:error)
} catch {
    DZError("Error in signin", error:error)
}

如果业务场景确实需要使用私有会话，无法依赖Amplify自动持久化登录状态，需手动实现凭证的存储与恢复逻辑，但这违背私有会话的设计初衷，不推荐该做法。

内容的提问来源于stack exchange，提问作者DanielZanchi