mongoose CastError: Cast to ObjectId failed for value

restfull路由如下：

router.get('/:id', controller.show);

mongoes代码如下：

exports.show = function(req, res) {

  Notice.findById(req.params.id, function (err, notice) {

    if(err) {

      res.json({no:0,msg:'获取失败:'+err});

    }else{

      var result = {no:1};

      result.obj=notice;

      res.json(result);

    }

  });

};

客户端访问：

http://192.168.0.165:9000/api/notices/11

打印结果如下;

{

"no": 0,

"msg": "获取失败:CastError: Cast to ObjectId failed for value \"11\" at path \"_id\""

}

具体原因参考：

http://stackoverflow.com/questions/14940660/whats-mongoose-error-cast-to-objectid-failed-for-value-xxx-at-path-id

Mongoose's findById method casts the id parameter to the type of the model's _id field so that it can properly query for the matching doc. This is an ObjectId but "11" is not a valid ObjectId so the cast fails.

 

如果客户端传递的是mongo ObjectId就不会报以上错误．例如以下访问方式：

http://192.168.0.165:9000/api/notices/41224d776a326fb40f000001 就不会报错．

{

"no": 1,

"obj": null

}

 

在正常情况下，客户端传递的id参数是从后台获取的ObjectId,但是为了严谨性现在做以下处理：

exports.show = function(req, res) {

  var id = req.params.id;



  if (id.match(/^[0-9a-fA-F]{24}$/)) {

    Notice.findById(id, function (err, notice) {

      if(err) {

        res.json({no:0,msg:'获取失败:'+err});

      }else{

        var result = {no:1};

        result.obj=notice;

        res.json(result);

      }

    });

  }else{

    res.json({no:0,msg:id+'不存在'});

  }



};