policyline/src/adapter.js

Attributes Based Access Control library for Node.JS

function optimize(exp) {
  let flag;
  do {
    flag = false;

    Object.keys(exp).forEach((key) => {
      if (key === '$or') {
        for (let i = exp[key].length - 1; i >= 0; i--) {
          let obj = exp[key][i];
          if (obj['$or']) {
            for (let j = obj['$or'].length - 1; j >= 0; j--) {
              exp[key].push(obj['$or'][j])
            }
            exp[key].splice(i, 1);
            flag = true;
          }
        }
      } else if (typeof exp[key] === 'object') {
        exp[key] = optimize(exp[key]);
      }
    });
  } while (flag);

  return exp;
}

const MongoJSONb = {

  and: (a, b) => (Object.assign(a, b)),

  or: (a, b) => ({
    '$or': [a, b]
  }),

  optimize: optimize,

  proceed: rules => {
    const OperatorMap = {
      '=': '$eq',	//Matches values that are equal to a specified value.
      '==': '$eq', //Matches values that are equal to a specified value.
      '!=': '$ne', //Matches all values that are not equal to a specified value.
      '>=': '$gte', //Matches values that are greater than or equal to a specified value.
      '>': '$gt',	//Matches values that are greater than a specified value.
      '<=': '$lte', //Matches values that are less than or equal to a specified value.
      '<': '$lt',	//Matches values that are less than a specified value.
      '~=': '$in', //Matches any of the values specified in an array.
      '^=': '$nin', //Matches none of the values specified in an array.
    };

    const MutatorMap = {
      'or': (rule, result, context) => {
        result[rule.attribute] = result[rule.attribute] || {
          '$or': []
        };
        result[rule.attribute]['$or'].push(rule.value);
      },
      'radius': (rule, result, context) => {
        context.radius = rule.value;
      },
      'inArea': (rule, result, context) => {
        result[rule.attribute] = {
          $near: {
            $geometry: {
              type: "Point",
              coordinates: rule.value
            },
            $maxDistance: 1000 * context.radius,
          }
        };
      }
    };

    // adapter logic
    const result = {}, context = {};
    let attribute;

    rules.forEach((rule) => {
      attribute = rule.attribute;

      if (rule.mutators.length) {
        // apply mutators
        rule.mutators.forEach((mutator) => {
          if (MutatorMap[mutator]) {
            context[rule.attribute] = context[rule.attribute] || {};
            MutatorMap[mutator](rule, result, context[rule.attribute]);
          }
        });
      } else {
        // apply attribute to result object
        if (result[attribute]) {
          result[attribute][OperatorMap[rule.operator]] = rule.value;
        } else {
          if (rule.operator === '=') {
            result[attribute] = rule.value;
          } else {
            result[attribute] = {
              [OperatorMap[rule.operator]]: rule.value
            }
          }
        }
      }
    });

    return result;
  }
};

const Adapter = {
  MongoJSONb: MongoJSONb,
};

export default Adapter;