Ruby mongodb驱动推送到数组

Question

假设我有一个文档Person，我想把Tags添加到这个文档中。

所以我想要一个文档看起来像

{ "_id" : 5,
  "tags" : ["Music", "Baseball", "Skiing"]
}

每当一个人选择了一个兴趣，我就把它添加到tags列表中。

这是我的尝试:

require 'mongo'
client = Mongo::Connection.new
db     = client['some_app']
coll   = db['persons']
coll.update({_id: 5}, {"$push" => {tags: "PS4"}}, {upsert: true}) 

如果我运行这个，我得到一个异常:

/usr/local/rvm/gems/ruby-2.1.2/gems/bson-1.10.2/lib/bson/bson_c.rb:20:in `serialize': key $push must not start with '$' (BSON::InvalidKeyName)

我做错了什么?

Answer 1

它看起来很好，并为我工作。以下更详尽的测试适用于我，请看看它是否适用于你，它应该有助于澄清你的问题，我怀疑你在发帖时丢失了。

test_unit.rb:

require 'mongo'
require 'test/unit'
require 'json'
class MyTest < Test::Unit::TestCase
  def setup
    @coll = Mongo::MongoClient.new['some_app']['persons']
    @coll.remove
  end
  test "BSON version" do
    assert_equal("1.10.2", CBson::VERSION, "confirm loading of C extension and version")
  end
  test "$push to existing doc" do
    json = %q{
      {
          "_id" : 5,
          "tags" : ["Music", "Baseball", "Skiing"]
      }
    }
    @coll.insert(JSON.parse(json))
    @coll.update({_id: 5}, {"$push" => {tags: "PS4"}}, {upsert: true})
    assert(@coll.find.to_a.first['tags'].include?('PS4'))
  end
  test "upsert and $push" do
    @coll.update({_id: 5}, {"$push" => {tags: "PS4"}}, {upsert: true})
    assert(@coll.find.to_a.first['tags'].include?('PS4'))
  end
end

ruby -v test_unit.rb

ruby 2.1.1p76 (2014-02-24 revision 45161) [x86_64-darwin12.0]
osprey:free-59705-mongo-push gjm$ ruby test_unit.rb
Loaded suite test_unit
Started
...
    Finished in 0.019441 seconds.
3 tests, 3 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed
154.31 tests/s, 154.31 assertions/s