javascript - 使用 Mongoose 和/或 underscore.js 实现 Mongo 查询和响应 'GroupBy'

Question

我们有一个 mongo 集合消息，其格式如下...

/* 0 */
{
  "text" : "A message to John",
  "created" : ISODate("2015-01-29T23:50:10.488Z"),
  "to" : {
    "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
    "name" : "John Smith"
  },
  "from" : {
    "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
    "name" : "Martin Fowler"
  },
}
/* 1 */
{
  "text" : "Another message to John",
  "created" : ISODate("2015-01-30T00:37:38.106Z"),
  "to" : {
    "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
    "name" : "John Smith"
  },
  "from" : {
    "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
    "name" : "Martin fowler"
  },
}

/* 2 */
{
  "text" : "Just another message to Jerry",
  "created" : ISODate("2015-01-30T00:37:38.106Z"),
  "to" : {
    "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
    "name" : "Jerry Jones"
  },
  "from" : {
    "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
    "name" : "Martin Fowler"
  },
}
/* 2 */
{
  "text" : "Message to Martin Fowler",
  "created" : ISODate("2015-01-30T00:37:38.106Z"),
  "to" : {
    "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
    "name" : "Martin Fowler"
  },
  "from" : {
    "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
    "name" : "Jerry Jones"
  },
}

我们需要以对话格式显示上面的数据，其中我们将每个对话分组在一起。对话意味着它可以是 to 或 from。

我们需要的数据格式示例如下:

{  
   "result":[  
      {  
         "id":"54bf1dc6c65b030c00faec0d",
         "name":"Jerry Jones",
         "messages":[  
            {
              "text" : "A message to John",
              "created" : ISODate("2015-01-29T23:50:10.488Z"),
              "to" : {
                "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
                "name" : "John Smith"
              },
              "from" : {
                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                "name" : "Martin Fowler"
              },
            }
            {
              "text" : "Another message to John",
              "created" : ISODate("2015-01-30T00:37:38.106Z"),
              "to" : {
                "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
                "name" : "John Smith"
              },
              "from" : {
                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                "name" : "Martin fowler"
              },
            }
         ]
      },
      {  
         "id":"54bf1e80eb5bf8800b0f5a8d",
         "name":"John Smith",
         "messages":[  
            {
              "text" : "Just another message to Jerry",
              "created" : ISODate("2015-01-30T00:37:38.106Z"),
              "to" : {
                "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
                "name" : "Jerry Jones"
              },
              "from" : {
                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                "name" : "Martin Fowler"
              },
            }
            {
              "text" : "Message to Martin Fowler",
              "created" : ISODate("2015-01-30T00:37:38.106Z"),
              "to" : {
                "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
                "name" : "Martin Fowler"
              },
              "from" : {
                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                "name" : "Jerry Jones"
              },
            }
         ]
      }
   ]
}

注意此查询始终在当前用户的上下文中进行，这就是为什么在每个对话中，我们都有一个_id以及代表对话中其他用户的name。对于上面的示例，当前用户将为Martin Fowler

我们尝试了几种不同的方法来实现这一目标，但仍然遇到问题。我宁愿求助于 Mongo/Node 社区，看看如何正确地完成它。我们正在将 mongoose 与 Node 一起使用，如果这有帮助的话......

我们当前的初始查询实现如下:

Message.find().or([{'from.id':req.user.id},{'to.id':req.user.id}]).exec(function(err,messages){

    //NEED TO IMPLEMENT THIS HERE CORRECTLY
});

注意，req.user.id 是当前用户的 ID

Answer 1

这个解决方案是对我之前针对类似问题的解决方案的轻微修改here .

相关文档的成员名称不一致。 Martin Folwer 在整个应用/数据库中应该是 Martin Fowler，而不是 Martin Fowler。 (注意小f)。您需要对您的文档进行此更改。

• $group 消息基于 to 和 from 字段组合在一起。构造一个组键 - “message_ Between”，值为a $concat to 和 from 字段中的值的结果。

• 从 Martin Fowler 发送至 Jerry Jones 和 Jerry Jones 的消息Martin Fowler 应被视为单个组。要实现我们让结果包含最后的名字按字母顺序，首先。所以我们的 key 来自 Martin 的所有消息
Fowler 到 Jerry Jones 和 Jerry Jones 到 Martin Fowler 将是马丁·福勒和杰瑞·琼斯。

代码:

Model.aggregate(
//match all those records which involve the user.
{$match:{$or:[{"to.name":req.user.id},
              {"from.name":req.user.id}]}},
{$group:{"_id":{
    "message_between":{
        $cond:[
            {
                $gt:[
                {$substr:["$to.name",0,1]},
                {$substr:["$from.name",0,1]}]
            },
            {$concat:["$to.name"," and ","$from.name"]},
            {$concat:["$from.name"," and ","$to.name"]}
        ]
    },"name":{$cond:[{$eq:["$to.name",
                           req.user.id]},
                     "$from.name",
                     "$to.name"]}
    },"messages":{$push:"$$ROOT"}
    }
},
{$project:{"_id":0,"name":"$_id.name","messages":1}}
,function(err,resp){
   // handle response.
})

o/p:

{
        "messages" : [
                {
                        "_id" : ObjectId("54d1d819b62f332e93fbb906"),
                        "text" : "Just another message to Jerry",
                        "created" : ISODate("2015-01-30T00:37:38.106Z"),
                        "to" : {
                                "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
                                "name" : "Jerry Jones"
                        },
                        "from" : {
                                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                                "name" : "Martin Fowler"
                        }
                },
                {
                        "_id" : ObjectId("54d1d819b62f332e93fbb907"),
                        "text" : "Message to Martin Fowler",
                        "created" : ISODate("2015-01-30T00:37:38.106Z"),
                        "to" : {
                                "id" : ObjectId("54bf1e80eb5bf8800b0f5a8d"),
                                "name" : "Martin Fowler"
                        },
                        "from" : {
                                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                                "name" : "Jerry Jones"
                        }
                }
        ],
        "name" : "Jerry Jones"
}
{
        "messages" : [
                {
                        "_id" : ObjectId("54d1d819b62f332e93fbb904"),
                        "text" : "A message to John",
                        "created" : ISODate("2015-01-29T23:50:10.488Z"),
                        "to" : {
                                "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
                                "name" : "John Smith"
                        },
                        "from" : {
                                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                                "name" : "Martin Fowler"
                        }
                },
                {
                        "_id" : ObjectId("54d1d819b62f332e93fbb905"),
                        "text" : "Another message to John",
                        "created" : ISODate("2015-01-30T00:37:38.106Z"),
                        "to" : {
                                "id" : ObjectId("54bf1dc6c65b030c00faec0d"),
                                "name" : "John Smith"
                        },
                        "from" : {
                                "id" : ObjectId("54bf1e1ceb5bf8800b0f5a8c"),
                                "name" : "Martin Fowler"
                        }
                }
        ],
        "name" : "John Smith"
}