MongoDB：在一个文档中获取所有集合

Question

I´ve got in some trouble with Javascript and mongoDB. I connected via:

var db = mongo.db(config.connectionString, { native_parser: true });

and bind my visitors collection db.bind('visitors'); . So after I tried to get all documents in there with that line:

db.visitors.find(function (err, visitors) {
   if (err) deferred.reject(err.name + ': ' + err.message);
   deferred.resolve(visitors);
});

So everything looks fine for me. But I get this error every time:

angular.js:12011 GET http://localhost:3000/api/visitors/getAll 400 (Bad Request)

I thought its something with my api so I tried ...findOne({_id:1},.. and that worked. So did I missed something ?

Answer 1

Yes it is wrong. It should be:

db.visitors.find({}, function (err, visitors) {
   if (err) deferred.reject(err.name + ': ' + err.message);
   deferred.resolve(visitors);
});

The parameters are:

collection.find(query[[[, fields], options], callback]);

It expects a query first then a callback and you're providing the callback in first place.

Your test with findOne() works because you're passing in a query via the {_ id: 1} object.

The documentation about MongoDB queries in Node.js is here .

Edit:

An example of using .find() and handling the cursor object in an async way by converting it to an array:

db.visitors.find({}).toArray(function (err, docs) {
    if (err) throw err;
    console.log(docs);
});

Answer 2

I think you missed the parameters part of the find() . Even if you don't want to look for something specific you have to pass an empty object in the parameters part. So it should look like find({}, function(){...});