mongodb 对于路径“_id”处的值 XXX，Mongoose 错误 Cast to ObjectId 失败是什么？
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What's Mongoose error Cast to ObjectId failed for value XXX at path "_id"?
提问by gremo
When sending a request to /customers/41224d776a326fb40f000001and a document with _id41224d776a326fb40f000001does not exist, docis nulland I'm returning a 404:
当发送一个请求/customers/41224d776a326fb40f000001，并用文件_id41224d776a326fb40f000001不存在，doc是null和我返回404：
Controller.prototype.show = function(id, res) {
this.model.findById(id, function(err, doc) {
if (err) {
throw err;
}
if (!doc) {
res.send(404);
}
return res.send(doc);
});
};
However, when _iddoes not match what Mongoose expects as "format" (I suppose) for example with GET /customers/fooa strange error is returned:
但是，当_id与 Mongoose 期望的“格式”（我想）不匹配时，例如GET /customers/foo返回一个奇怪的错误：
CastError: Cast to ObjectId failed for value "foo" at path "_id".
CastError：对于路径“_id”处的值“foo”，强制转换为 ObjectId 失败。
So what's this error?
那么这个错误是什么？
回答by JohnnyHK
Mongoose's findByIdmethod casts the idparameter to the type of the model's _idfield so that it can properly query for the matching doc. This is an ObjectId but "foo"is not a valid ObjectId so the cast fails.
Mongoose 的findById方法将id参数转换为模型_id字段的类型，以便它可以正确查询匹配的文档。这是一个 ObjectId 但"foo"不是有效的 ObjectId，因此转换失败。
This doesn't happen with 41224d776a326fb40f000001because that string is a valid ObjectId.
这不会发生，41224d776a326fb40f000001因为该字符串是有效的 ObjectId。
One way to resolve this is to add a check prior to your findByIdcall to see if idis a valid ObjectId or not like so:
解决此问题的一种方法是在findById调用之前添加检查以查看是否id是有效的 ObjectId 或不像这样：
if (id.match(/^[0-9a-fA-F]{24}$/)) {
// Yes, it's a valid ObjectId, proceed with `findById` call.
}
回答by xpepermint
Use existing functions for checking ObjectID.
使用现有函数检查 ObjectID。
var mongoose = require('mongoose');
mongoose.Types.ObjectId.isValid('your id here');
回答by gustavohenke
Are you parsing that string as ObjectId?
您是否将该字符串解析为ObjectId？
Here in my application, what I do is:
在我的应用程序中，我所做的是：
ObjectId.fromString( myObjectIdString );
回答by Ryan Dhungel
I had to move my routes on top of other routes that are catching the route parameters:
我不得不将我的路线移动到捕获路线参数的其他路线之上：
// require express and express router
const express = require("express");
const router = express.Router();
// move this `/post/like` route on top
router.put("/post/like", requireSignin, like);
// keep the route with route parameter `/:postId` below regular routes
router.get("/post/:postId", singlePost);
回答by s.babar
I have the same issue I add
_id: String .in schema then it start work
我有同样的问题，我添加了
_id: String .in schema 然后它开始工作
回答by yogesh agrawal
if(mongoose.Types.ObjectId.isValid(userId.id)) {
User.findById(userId.id,function (err, doc) {
if(err) {
reject(err);
} else if(doc) {
resolve({success:true,data:doc});
} else {
reject({success:false,data:"no data exist for this id"})
}
});
} else {
reject({success:"false",data:"Please provide correct id"});
}
best is to check validity
最好是检查有效性
回答by Crowdpleasr
In my case, I had to add _id: Objectinto my Schema, and then everything worked fine.
就我而言，我必须添加_id: Object到我的架构中，然后一切正常。
回答by Brajalal Pal
//Use following to check if the id is a valid ObjectId?
var valid = mongoose.Types.ObjectId.isValid(req.params.id);
if(valid)
{
//process your code here
} else {
//the id is not a valid ObjectId
}
回答by ZEE
You can also use ObjectId.isValid like the following :
您还可以使用 ObjectId.isValid 如下：
if (!ObjectId.isValid(userId)) return Error({ status: 422 })
回答by think-serious
As of Nov 19, 2019
截至 2019 年 11 月 19 日
You can use isValidObjectId(id)from mongoose version 5.7.12
您可以isValidObjectId(id)从 mongoose 版本 5.7.12 开始使用
https://mongoosejs.com/docs/api/mongoose.html#mongoose_Mongoose-isValidObjectId
https://mongoosejs.com/docs/api/mongoose.html#mongoose_Mongoose-isValidObjectId
