使用Keyloak脚本映射器聚合声明中的角色属性

2022-03-27 00:00:00 keycloak java nashorn

我们有一个Keyloak脚本映射器来将角色属性添加到ID令牌。目标是聚合角色属性中的可用值。映射器如下所示:

/**
 * Merge with concatenation for the values of attributes obtained
 * from the token with the attributes obtained from the roles. If for
 * example a group and a role have the same attribute key, the values
 * for that key from the group and role will be concatenated.
 *
 * Known limitations:
 * When only roles have a certain attribute, and not a group, the 
 * mapper only uses the first role it can find. Bug was difficult to
 * fix because state in the variable currentClaims seems to be
 * persisted over multiple calls.
 * Workaround: Also add this specific attribute to a group with a
 * dummy value.
 * 
 * NOTE: there is no role attribute mapper out-of-the-box in 
 * Keycloak.
 * 
 * Available variables in script: 
 * user - the current user
 * realm - the current realm
 * token - the current token
 * userSession - the current userSession
 * keycloakSession - the current keycloakSession
 * 
 * Documentation on available variables:
 * https://stackoverflow.com/a/52984849
 */
 
var currentClaims = {};
token.getOtherClaims().forEach(function(k, v) {
  currentClaims[k] = v;
});

function isMultiValued(v) {
  // From experience, multivalued attribute values are sometimes 
  // Arrays and sometimes Objects. Thus look for negative case:
  // anything other than a string is multivalued.
  return !(typeof v === 'string' || v instanceof String);
}

function addToList(l, values) {
  for each(var v in values) {
    l.add(v);
  }
  return l;
}

function toStringArray(arr) {
  return Java.to(arr, "java.lang.String[]");
}

user.getRealmRoleMappings().forEach(function(roleModel) {
  roleModel.getAttributes().forEach(function(k, v) {
    var currentValue = currentClaims[k];
    if (k in currentClaims) {
      if (!isMultiValued(currentValue)) {
        v = toStringArray([currentValue].concat(v));
      } else {
        v = addToList(currentValue, v);
      }
    }
    currentClaims[k] = v; // <= to also aggregate over roles!
    token.setOtherClaims(k, v); 
  }); 
});

添加了currentClaims[k] = v的部分以聚合角色中的可用值,因此,如果两个角色包含相同属性,则它们的值也会聚合。

例如,如果我们有一个用户的角色a和b的属性foo的值分别为1和2,则我们预计ID令牌将包含值为1和2的foo的声明。

user:
  role a foo -> 1
  role b foo -> 2
expected ID token:
  foo -> [1, 2]

但在当前代码中,currentClaims变量似乎在多次调用函数时保持状态。每次检查ID令牌时,都会将更多2的值添加到令牌中,从而导致类似[1, 2, 2, ..., 2]的foo声明,每次检索令牌时都会添加越来越多的2。我尝试将整个调用包装在一个函数中,以便可能在调用之间丢弃状态,但无济于事。结果如下:

为什么在多个呼叫期间保留状态?有没有办法也聚合角色属性的值?


解决方案

为什么在多个调用期间保留状态?

未知。也许是和纳肖恩有关的事。

[i]有没有办法也聚合角色属性的值?

要不保持聚合值,请在addToList函数中检查它是否已经存在(解决方法):

function addToList(l, values) {
  for each(var v in values) {
    if (!l.contains(v)) {
      l.add(v);
    }
  }
  return l;
}

并通过保持某种状态进行聚合:

var newClaims = {};
newClaims = currentClaims;
user.getRealmRoleMappings().forEach(function(roleModel) {
  roleModel.getAttributes().forEach(function(k, v) {
    var currentValue = newClaims[k];
    if (k in newClaims) {
      if (isMultiValued(currentValue)) {
        v = addToList(currentValue, v);
      }
    }
    newClaims[k] = v;
  }); 
});
token.setOtherClaims("new-claims", newClaims); 

这会将new-claims字段中的所有索赔放入JWT。

/编辑:

注意:addToList中的此JavaScript/Java互操作存在问题(如更改角色的实际属性.)。最好使用纯JavaScript进行连接,然后再转换回Java:

function toStringArray(arr) {
  return Java.to(arr, "java.lang.String[]");
}


Array.prototype.includes = function(obj) {
  var i = this.length;
  while (i--) {
    if (this[i] === obj) {
      return true;
    }
  }
  return false;
}

function addToList(l, values) {
  // Add values to new instance to avoid magical addition to
  // current values in role attributes
  var arr = [];
  for each(var v in l) {
    arr.push(v);
  }
  for each(var v in values) {
    if (!arr.includes(v)) {
      arr.push(v);
    }
  }
  return toStringArray(arr);
}

相关文章