为什么我不能在 nodejs 和 mongodb 中多次发出 post 请求

Question

我创建了一个评论系统。我可以发表评论（创建新评论）一次。当我尝试在同一个帖子上创建另一个评论时，它会出错。请帮帮我。

我第二次尝试在 postman 上创建新评论时收到的错误消息

{
"driver": true,
"name": "MongoError",
"index": 0,
"code": 11000,
"keyPattern": {
    "title": 1
},
"keyValue": {
    "title": null
}
}

后模型

//creating the user models for the database

   const mongoose = require("mongoose"); //import mongoose
   const Schema = mongoose.Schema;

  const PostSchema = new mongoose.Schema(
   {
   
    title:{
        type: String,
        required: true,
        unique: true,
    },
    description:{
        type: String,
        required: true, 
    },
    postPhoto:{
        type: String,
        required:false,
    },
   username:{
        type: Schema.Types.ObjectId, 
        ref: 'User'
    },
    categories:{
       type: Array,
    },
   comments: [{
         type: mongoose.Schema.Types.ObjectId,
         ref: 'Comment'
       }]
   
    }, {timestamps: true},

   );
  //exporting this schema
 module.exports = mongoose.model("Post", PostSchema); //the module name is "Post"

用户模型

//creating the user models for the database

  const mongoose = require("mongoose"); //import mongoose

  const UserSchema = new mongoose.Schema({

    username:{
        type: String,
        required: true,
        unique: true
    },
    email:{
        type: String,
        required: true,
        unique: true
    },
    password:{
        type: String,
        required: true
    },
    profilePicture:{
        type: String,
        default: "",
    },
  }, {timestamps: true}
 );
//exporting this schema
module.exports = mongoose.model("User", UserSchema); //the module name is "User"

评论模型

const mongoose = require("mongoose"); //import mongoose to be used
 const Schema = mongoose.Schema;

  const CommentSchema = new mongoose.Schema(
   {
    description:{
        type: Array,
        required: true, 
    },
   author:{
        type: Schema.Types.ObjectId, 
        ref: 'User'
    },
   
  postId:{
      type: Schema.Types.ObjectId, 
        ref: 'Post',
         partialFilterExpression: { postId: { $type: 'string' } }
  }
  }, {timestamps: true}
  );
  //exporting this schema
 module.exports = mongoose.model("Comment", CommentSchema); //the module name is "Post"

评论路线路径

router.post("/posts/:id/comment", async (req, res) =>{
const newComment = new Comment(req.body);//we create a new comment for the database
    
try{
    const savedComment = await newComment.save();//we need to try and catch the new comment and save it

    const currentPost = await Post.findById(req.params.id)//we need to find the post that has the comment via the id
        currentPost.comments.push(savedComment)//we need to push the comment into the post

        await currentPost.save()//we saved the new post with the comment
    res.status(200).json(currentPost)
  }catch(err){
    res.status(500).json(err)
 }
  })

我的邮递员设置和错误的屏幕截图

Answer 1

const currentPost = await Comment.create({
        createdBy : req.params.id,
        postId:  req.params.postId,
        description,
    })

总之，一切都会由你的 URL 参数携带 postman body 只会用于描述 body