无法读取未定义的 属性 'connector'

Cannot read property 'connector' of undefined

 {
  "error": {
    "statusCode": 500,
    "name": "TypeError",
    "message": "Cannot read property 'connector' of undefined",
    "stack": "TypeError: Cannot read property 'connector' of undefined\n    at Function.Projects.getProjectData (F:\SanWork\AngularWorkSpace\jobMngt\common\models\projects.js:7:44)\n    at SharedMethod.invoke (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\shared-method.js:263:25)\n    at HttpContext.invoke (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\http-context.js:389:12)\n    at phaseInvoke (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\remote-objects.js:654:9)\n    at runHandler (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\lib\phase.js:135:5)\n    at iterate (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:146:13)\n    at Object.async.eachSeries (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:162:9)\n    at runHandlers (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\lib\phase.js:144:13)\n    at iterate (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:146:13)\n    at F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:157:25\n    at F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:154:25\n    at execStack (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\remote-objects.js:493:7)\n    at RemoteObjects.execHooks (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\remote-objects.js:497:10)\n    at phaseBeforeInvoke (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\strong-remoting\lib\remote-objects.js:650:10)\n    at runHandler (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\lib\phase.js:135:5)\n    at iterate (F:\SanWork\AngularWorkSpace\jobMngt\node_modules\loopback-phase\node_modules\async\lib\async.js:146:13)"
  }
}

使用此代码时出现此错误,我想知道导致错误的原因以及任何可能的修复方法。

型号代码:

  'use strict';

module.exports = function(Projects) {
Projects.getProjectData = function(cb) {
        var sql = 'select * from projects';
        // call sql query from postreSQL
        Projects.app.datasources.postgres.connector.query(sql, function(err, result) {
            if (err) {
                console.log('Error retrieving projects result ...');
                console.log(err);
                return cb(err);
            }
            cb(err, result[0].jsondata);
        });
    }
    Projects.remoteMethod(
        'getProjectData', {
            returns: [{
                type: 'string',
                required: true,
                root: true
            }],
            http: {
                verb: 'get'
            }
        }
    );
};

我已经安装了 loopback-connector-postgresql 并生成了模型,但是当我尝试编写自定义 api 时出现错误。

module.exports 声明之前

var app = require('../../server/server.js');

这是假设您位于公共文件夹的模型目录中。

然后使用 app.datasource

而不是 Projects.app.datasource