463 lines
14 KiB
JavaScript
463 lines
14 KiB
JavaScript
/*!
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Schema ACL options
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Object level permissions, for example, an album owned by a user
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Factors to be authorized against:
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* model name: Album
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* model instance properties: userId of the album, friends, shared
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* methods
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* app and/or user ids/roles
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** loggedIn
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** roles
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** userId
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** appId
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** none
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** everyone
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** relations: owner/friend/granted
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Class level permissions, for example, Album
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* model name: Album
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* methods
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URL/Route level permissions
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* url pattern
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* application id
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* ip addresses
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* http headers
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Map to oAuth 2.0 scopes
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*/
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var loopback = require('../../lib/loopback');
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var async = require('async');
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var assert = require('assert');
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var debug = require('debug')('loopback:security:acl');
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var ctx = require('../../lib/access-context');
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var AccessContext = ctx.AccessContext;
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var Principal = ctx.Principal;
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var AccessRequest = ctx.AccessRequest;
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var Role = loopback.Role;
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assert(Role, 'Role model must be defined before ACL model');
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/**
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* A Model for access control meta data.
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*
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* System grants permissions to principals (users/applications, can be grouped
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* into roles).
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*
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* Protected resource: the model data and operations
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* (model/property/method/relation/…)
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*
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* For a given principal, such as client application and/or user, is it allowed
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* to access (read/write/execute)
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* the protected resource?
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*
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* @header ACL
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* @property {String} model Name of the model.
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* @property {String} property Name of the property, method, scope, or relation.
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* @property {String} accessType Type of access being granted: one of READ, WRITE, or EXECUTE.
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* @property {String} permission Type of permission granted. One of:
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* - ALARM: Generate an alarm, in a system-dependent way, the access specified in the permissions component of the ACL entry.
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* - ALLOW: Explicitly grants access to the resource.
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* - AUDIT: Log, in a system-dependent way, the access specified in the permissions component of the ACL entry.
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* - DENY: Explicitly denies access to the resource.
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* @property {String} principalType Type of the principal; one of: Application, Use, Role.
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* @property {String} principalId ID of the principal - such as appId, userId or roleId
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*
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* @class ACL
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* @inherits PersistedModel
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*/
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module.exports = function(ACL) {
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ACL.ALL = AccessContext.ALL;
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ACL.DEFAULT = AccessContext.DEFAULT; // Not specified
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ACL.ALLOW = AccessContext.ALLOW; // Allow
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ACL.ALARM = AccessContext.ALARM; // Warn - send an alarm
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ACL.AUDIT = AccessContext.AUDIT; // Audit - record the access
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ACL.DENY = AccessContext.DENY; // Deny
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ACL.READ = AccessContext.READ; // Read operation
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ACL.WRITE = AccessContext.WRITE; // Write operation
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ACL.EXECUTE = AccessContext.EXECUTE; // Execute operation
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ACL.USER = Principal.USER;
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ACL.APP = ACL.APPLICATION = Principal.APPLICATION;
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ACL.ROLE = Principal.ROLE;
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ACL.SCOPE = Principal.SCOPE;
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/**
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* Calculate the matching score for the given rule and request
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* @param {ACL} rule The ACL entry
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* @param {AccessRequest} req The request
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* @returns {Number}
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*/
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ACL.getMatchingScore = function getMatchingScore(rule, req) {
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var props = ['model', 'property', 'accessType'];
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var score = 0;
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for (var i = 0; i < props.length; i++) {
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// Shift the score by 4 for each of the properties as the weight
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score = score * 4;
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var val1 = rule[props[i]] || ACL.ALL;
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var val2 = req[props[i]] || ACL.ALL;
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var isMatchingMethodName = props[i] === 'property' && req.methodNames.indexOf(val1) !== -1;
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if (val1 === val2 || isMatchingMethodName) {
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// Exact match
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score += 3;
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} else if (val1 === ACL.ALL) {
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// Wildcard match
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score += 2;
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} else if (val2 === ACL.ALL) {
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// Doesn't match at all
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score += 1;
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} else {
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return -1;
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}
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}
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// Weigh against the principal type into 4 levels
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// - user level (explicitly allow/deny a given user)
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// - app level (explicitly allow/deny a given app)
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// - role level (role based authorization)
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// - other
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// user > app > role > ...
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score = score * 4;
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switch (rule.principalType) {
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case ACL.USER:
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score += 4;
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break;
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case ACL.APP:
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score += 3;
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break;
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case ACL.ROLE:
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score += 2;
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break;
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default:
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score += 1;
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}
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// Weigh against the roles
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// everyone < authenticated/unauthenticated < related < owner < ...
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score = score * 8;
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if (rule.principalType === ACL.ROLE) {
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switch (rule.principalId) {
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case Role.OWNER:
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score += 4;
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break;
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case Role.RELATED:
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score += 3;
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break;
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case Role.AUTHENTICATED:
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case Role.UNAUTHENTICATED:
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score += 2;
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break;
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case Role.EVERYONE:
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score += 1;
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break;
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default:
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score += 5;
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}
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}
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score = score * 4;
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score += AccessContext.permissionOrder[rule.permission || ACL.ALLOW] - 1;
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return score;
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};
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/**
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* Get matching score for the given `AccessRequest`.
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* @param {AccessRequest} req The request
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* @returns {Number} score
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*/
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ACL.prototype.score = function(req) {
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return this.constructor.getMatchingScore(this, req);
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}
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/*!
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* Resolve permission from the ACLs
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* @param {Object[]) acls The list of ACLs
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* @param {Object} req The request
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* @returns {AccessRequest} result The effective ACL
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*/
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ACL.resolvePermission = function resolvePermission(acls, req) {
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if (!(req instanceof AccessRequest)) {
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req = new AccessRequest(req);
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}
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// Sort by the matching score in descending order
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acls = acls.sort(function(rule1, rule2) {
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return ACL.getMatchingScore(rule2, req) - ACL.getMatchingScore(rule1, req);
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});
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var permission = ACL.DEFAULT;
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var score = 0;
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for (var i = 0; i < acls.length; i++) {
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score = ACL.getMatchingScore(acls[i], req);
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if (score < 0) {
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// the highest scored ACL did not match
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break;
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}
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if (!req.isWildcard()) {
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// We should stop from the first match for non-wildcard
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permission = acls[i].permission;
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break;
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} else {
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if (req.exactlyMatches(acls[i])) {
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permission = acls[i].permission;
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break;
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}
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// For wildcard match, find the strongest permission
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if (AccessContext.permissionOrder[acls[i].permission]
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> AccessContext.permissionOrder[permission]) {
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permission = acls[i].permission;
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}
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}
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}
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if (debug.enabled) {
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debug('The following ACLs were searched: ');
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acls.forEach(function(acl) {
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acl.debug();
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debug('with score:', acl.score(req));
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});
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}
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var res = new AccessRequest(req.model, req.property, req.accessType,
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permission || ACL.DEFAULT);
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return res;
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};
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/*!
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* Get the static ACLs from the model definition
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* @param {String} model The model name
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* @param {String} property The property/method/relation name
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*
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* @return {Object[]} An array of ACLs
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*/
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ACL.getStaticACLs = function getStaticACLs(model, property) {
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var modelClass = loopback.findModel(model);
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var staticACLs = [];
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if (modelClass && modelClass.settings.acls) {
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modelClass.settings.acls.forEach(function(acl) {
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if (!acl.property || acl.property === ACL.ALL
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|| property === acl.property) {
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staticACLs.push(new ACL({
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model: model,
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property: acl.property || ACL.ALL,
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principalType: acl.principalType,
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principalId: acl.principalId, // TODO: Should it be a name?
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accessType: acl.accessType || ACL.ALL,
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permission: acl.permission
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}));
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}
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});
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}
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var prop = modelClass &&
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(modelClass.definition.properties[property] // regular property
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|| (modelClass._scopeMeta && modelClass._scopeMeta[property]) // relation/scope
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|| modelClass[property] // static method
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|| modelClass.prototype[property]); // prototype method
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if (prop && prop.acls) {
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prop.acls.forEach(function(acl) {
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staticACLs.push(new ACL({
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model: modelClass.modelName,
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property: property,
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principalType: acl.principalType,
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principalId: acl.principalId,
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accessType: acl.accessType,
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permission: acl.permission
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}));
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});
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}
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return staticACLs;
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};
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/**
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* Check if the given principal is allowed to access the model/property
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* @param {String} principalType The principal type.
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* @param {String} principalId The principal ID.
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* @param {String} model The model name.
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* @param {String} property The property/method/relation name.
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* @param {String} accessType The access type.
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* @callback {Function} callback Callback function.
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* @param {String|Error} err The error object
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* @param {AccessRequest} result The access permission
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*/
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ACL.checkPermission = function checkPermission(principalType, principalId,
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model, property, accessType,
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callback) {
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if (principalId !== null && principalId !== undefined && (typeof principalId !== 'string')) {
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principalId = principalId.toString();
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}
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property = property || ACL.ALL;
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var propertyQuery = (property === ACL.ALL) ? undefined : {inq: [property, ACL.ALL]};
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accessType = accessType || ACL.ALL;
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var accessTypeQuery = (accessType === ACL.ALL) ? undefined : {inq: [accessType, ACL.ALL]};
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var req = new AccessRequest(model, property, accessType);
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var acls = this.getStaticACLs(model, property);
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var resolved = this.resolvePermission(acls, req);
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if (resolved && resolved.permission === ACL.DENY) {
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debug('Permission denied by statically resolved permission');
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debug(' Resolved Permission: %j', resolved);
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process.nextTick(function() {
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callback && callback(null, resolved);
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});
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return;
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}
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var self = this;
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this.find({where: {principalType: principalType, principalId: principalId,
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model: model, property: propertyQuery, accessType: accessTypeQuery}},
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function(err, dynACLs) {
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if (err) {
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callback && callback(err);
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return;
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}
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acls = acls.concat(dynACLs);
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resolved = self.resolvePermission(acls, req);
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if (resolved && resolved.permission === ACL.DEFAULT) {
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var modelClass = loopback.findModel(model);
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resolved.permission = (modelClass && modelClass.settings.defaultPermission) || ACL.ALLOW;
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}
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callback && callback(null, resolved);
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});
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};
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ACL.prototype.debug = function() {
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if (debug.enabled) {
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debug('---ACL---');
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debug('model %s', this.model);
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debug('property %s', this.property);
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debug('principalType %s', this.principalType);
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debug('principalId %s', this.principalId);
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debug('accessType %s', this.accessType);
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debug('permission %s', this.permission);
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}
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}
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/**
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* Check if the request has the permission to access.
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* @options {Object} context See below.
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* @property {Object[]} principals An array of principals.
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* @property {String|Model} model The model name or model class.
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* @property {*} id The model instance ID.
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* @property {String} property The property/method/relation name.
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* @property {String} accessType The access type: READE, WRITE, or EXECUTE.
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* @param {Function} callback Callback function
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*/
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ACL.checkAccessForContext = function(context, callback) {
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if (!(context instanceof AccessContext)) {
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context = new AccessContext(context);
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}
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var model = context.model;
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var property = context.property;
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var accessType = context.accessType;
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var modelName = context.modelName;
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var methodNames = context.methodNames;
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var propertyQuery = (property === ACL.ALL) ? undefined : {inq: methodNames.concat([ACL.ALL])};
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var accessTypeQuery = (accessType === ACL.ALL) ? undefined : {inq: [accessType, ACL.ALL]};
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var req = new AccessRequest(modelName, property, accessType, ACL.DEFAULT, methodNames);
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var effectiveACLs = [];
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var staticACLs = this.getStaticACLs(model.modelName, property);
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var self = this;
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var roleModel = loopback.getModelByType(Role);
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this.find({where: {model: model.modelName, property: propertyQuery,
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accessType: accessTypeQuery}}, function(err, acls) {
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if (err) {
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callback && callback(err);
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return;
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}
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var inRoleTasks = [];
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acls = acls.concat(staticACLs);
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acls.forEach(function(acl) {
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// Check exact matches
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for (var i = 0; i < context.principals.length; i++) {
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var p = context.principals[i];
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if (p.type === acl.principalType
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&& String(p.id) === String(acl.principalId)) {
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effectiveACLs.push(acl);
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return;
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}
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}
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// Check role matches
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if (acl.principalType === ACL.ROLE) {
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inRoleTasks.push(function(done) {
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roleModel.isInRole(acl.principalId, context,
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function(err, inRole) {
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if (!err && inRole) {
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effectiveACLs.push(acl);
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}
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done(err, acl);
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});
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});
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}
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});
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async.parallel(inRoleTasks, function(err, results) {
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if (err) {
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callback && callback(err, null);
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return;
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}
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var resolved = self.resolvePermission(effectiveACLs, req);
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if (resolved && resolved.permission === ACL.DEFAULT) {
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resolved.permission = (model && model.settings.defaultPermission) || ACL.ALLOW;
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}
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debug('---Resolved---');
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resolved.debug();
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callback && callback(null, resolved);
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});
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});
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};
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/**
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* Check if the given access token can invoke the method
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* @param {AccessToken} token The access token
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* @param {String} model The model name
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* @param {*} modelId The model id
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* @param {String} method The method name
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* @callback {Function} callback Callback function
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* @param {String|Error} err The error object
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* @param {Boolean} allowed is the request allowed
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*/
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ACL.checkAccessForToken = function(token, model, modelId, method, callback) {
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assert(token, 'Access token is required');
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var context = new AccessContext({
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accessToken: token,
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model: model,
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property: method,
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method: method,
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modelId: modelId
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});
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this.checkAccessForContext(context, function(err, access) {
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if (err) {
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callback && callback(err);
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return;
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}
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callback && callback(null, access.permission !== ACL.DENY);
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});
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};
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}
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