为什么 Spring Social 插件偶尔会在 User 类上返回空邮件？

Question

我有一个 Grails 项目 (v2.4.2)，它使用 spring-security-facebook:0.17 插件通过 Spring Security 进行身份验证。乍一看，一切似乎都很好。但是，由于某些未知原因，我无法访问大量用户的电子邮件地址。我正在使用 spring social 来获取电子邮件。我有权限，它设置在范围内。这是我验证新用户的代码 sn-p：

log.info("Create domain for facebook user $token.uid")

//Use Spring Social Facebook to load details for current user from Facebook API
log.info("create: FacebookAuthToken: $token")
log.info("created FacebookAuthToken.FacebookAccessToken = ${token.accessToken}")

Facebook facebook = new FacebookTemplate(token.accessToken.accessToken)

org.springframework.social.facebook.api.User fbProfile = facebook.userOperations().getUserProfile()

// Check if email is actual granted because in production some are coming back null
boolean isEmailGranted=false
List<Permission> permissions = facebook?.userOperations()?.getUserPermissions()
String permissionString = "["
for (int i=0;i<permissions.size();i++) {
    permissionString += "["+ permissions[i].getName() + ":" + permissions[i].getStatus()+"]"
    if (permissions[i].getName()=="email" && permissions[i].isGranted())
        isEmailGranted=true
}
permissionString += "]"
log.info("create: Facebook Permissions = " + permissionString)

def grailsWebRequest = WebUtils.retrieveGrailsWebRequest()
def flash = grailsWebRequest.flashScope

if (!isEmailGranted) {
    log.warn("create: Unable to subscribe facebook user because email priviledge was not granted.")
    flash.message = 'Login to Facebook failed. We must have access to your email address in order to proceed with login.'
    throw new InsufficientAuthenticationException("Facebook email not accessible")
}

log.info("created: ")

String email = fbProfile.getEmail()
String firstName = fbProfile.getFirstName()
String lastName = fbProfile.getLastName()
String fullName = fbProfile.getName()
String username = firstName
String password = token.accessToken.accessToken

if (!email) {
    log.error("create: Permission was granted to use facebook email but the value is null.")
    flash.message = 'Login to Facebook failed. We are temporarily unable to access your email although permission has been granted'
    throw new InsufficientAuthenticationException("Facebook email not accessible for unknown reason")
}

为什么在获得许可后我会收到一封空电子邮件？是否有处理这种行为的首选方法（除了身份验证失败和伪造电子邮件地址）。非常感谢！

Answer 1

“用户”对象 (https://developers.facebook.com/docs/reference/api/user/) 的“电子邮件”字段的文档阐明了此处的预期行为，即： "如果没有可用的有效电子邮件地址，则不会返回此字段"

有一个关于不发送电子邮件的不同情况的详细说明。请检查一下： https://developers.facebook.com/bugs/298946933534016/

希望对你有帮助。