OData - Strange index with MongoDB [Mongoose: Cast Error]

问题

I have some MongoDB documents with this schema:

Id: {type: "id", key: true, computed: true, nullable: false},
Name: {type: "string", nullable: false, maxLength: 50}

and these documents are exposed as OData by a small web application (I'm using Express, JayData, and Mongoose). These are some of those documents:

{ "_id" : ObjectId("5343fd656b9c5c084b8f2a70"), "Name" : "Service74"},
{ "_id" : ObjectId("5343fd656b9c5c084b8f2a6f"), "Name" : "Service73"},
{ "_id" : ObjectId("5343fd656b9c5c084b8f2a6e"), "Name" : "Service72"},
...

If I type this address http://localhost:8080/marketplace/Services('5343fd656b9c5c084b8f2a70') which correspond to Service74 I get this result:

...
<d:Id>NTM0M2ZkNjU2YjljNWMwODRiOGYyYTcw</d:Id>
<d:Name>Service74</d:Name>
...

Of course If I use the Id specified in the result I obtain the same page.

The problem occurs when I try to use the mongoose function findById:

app.post("/addCompare/:id", function(req, res) {
    console.log(req.params.id);
    Services.findById(req.params.id, function(err, service) {
        if(!err) {console.log(service);}
        else {console.log(err);}
    });
    res.send(200);
});

I get this NTM0M2ZkNjU2YjljNWMwODRiOGYyYTcw and then this error:

{ message: 'Cast to ObjectId failed for value "NTM0M2ZkNjU2YjljNWMwODRiOGYyYTU5" at path "_id"',
  name: 'CastError',
  type: 'ObjectId',
  value: 'NTM0M2ZkNjU2YjljNWMwODRiOGYyYTU5',
  path: '_id' }

Where am I wrong? Tell me if I miss some other information...

Thanks.

PS: I found a similar problem here Mongoose: Cast to ObjectId failed, but if I change the model definition for Mongoose (in which actually I don't declare the id) by including this definition:

var serviceSchema = mongoose.Schema({
    _id: String,
    ...

nothing changes...

回答1:

The 5343fd656b9c5c084b8f2a70 is the internal identifier of the entity that is used on the server-side. This value is base64-encoded over OData, this is why you receive NTM0M2ZkNjU2YjljNWMwODRiOGYyYTcw in the Id field. The entity can be easily retrieved by Id by calling atob(req.params.id) on the received Id.

来源：https://stackoverflow.com/questions/23062042/odata-strange-index-with-mongodb-mongoose-cast-error

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mongodb

express

mongoose

odata

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