MongoDB-使用参数id的findOne导致空对象或错误

Question

I'm learning Express/Mongo(using mLab) by building a simple little app that I can create a list of clients and a single client detail page.

localhost:3000/clients renders the entire collection of ' clients '

localhost:3000/clients/:id should render the specific client by id

This is a collection: clients entry example from MongoDB (mLab):

{
    "_id": {
        "$oid": "57ba01d3ab462a0aeec66646"
    },
    "name": "ClientName",
    "address": {
        "street": "StreetName",
        "city": "Cityname",
        "state": "Statename",
        "zip": "1234"
    },
    "createDate": {
        "$date": "2016-08-21T19:32:35.525Z"
    }
}

I successfully created an href on the /clients page with the id value that links to the specific client:

<a href="/clients/<%= client._id %>"><%= client.name %></a>

Which correctly results in this:

http://localhost:3000/clients/57ba01d3ab462a0aeec66646

Here is my get function for /clients/:id :

app.get('/clients/:id', (req, res) => {
  db.collection('clients').findOne(req.params.id, (err, result) => {
    if (err) {
      handleError(res, err.message, "Failed to get clients.");
    } else {
      console.log(result);
      res.render('client.ejs', {client: result})
    }
  });
})

Clicking on the link results in the following error:

MongoError: query selector must be an object at Function.MongoError.create (/Users/username/Desktop/node/node_modules/mongodb-core/lib/error.js:31:11) at Collection.find [...]

I've been reading and searching all afternoon and trying a ton of different options like:

• 'You need to create an ObjectID': https://stackoverflow.com/a/10929670
• 'You need to use Mongoose to create the ObjectID': https://stackoverflow.com/a/30652361

Do I really need Mongoose? This seems like a foundational thing to do it Mongo — why isn't it working?

Answer 1

you need to use an object : {id: req.params.id}

app.get('/clients/:id', (req, res) => {
  db.collection('clients').findOne({_id: req.params.id}, (err, result) => {
    if (err) {
      handleError(res, err.message, "Failed to get clients.");
    } else {
      console.log(result);
      res.render('client.ejs', {client: result})
    }
  });
})

Answer 2

You need to convert req.params.id to MongoObject and then use it:

var id = new ObjectID(req.params.id);

Answer 3

也许像这样：

 db.collection('clients').findOne({"_id.$oid": req.params.id}, (err, result) =>