在哪里可以找到我的代码中模型“ Item”的路径“ _id”的值“ create”的Cast to ObjectId的源失败

Question

I'm creating an inventory App for the odin project's Nodejs project whilist following the MDN's Express.js tutorial. I can delete items, update items and read items, but when I want to create items I get the error mentioned (Cast to ObjectId failed for value "create" at path "_id" for model "Items").

I've looked through all my code and when I tried to replace what was in "items_create_get" the error never changed which lead me to believe that it is not the issue.

//itemsController.js:
var Items = require("../models/items");
var async = require("async");
const { body, validationResult } = require("express-validator/check");
const { sanitizeBody } = require("express-validator/filter");

exports.items_create_post = [
// Convert the category to an array.
(req, res, next) => {
if (!(req.body.category instanceof Array)) {
    if (typeof req.body.category === "undefined") 
        req.body.category = [];
    else req.body.category = new Array(req.body.category);
}
    next();
},

// Handle items create on POST.
exports.items_create_post = [
   // Convert the category to an array.
    (req, res, next) => {
        if (!(req.body.category instanceof Array)) {
            if (typeof req.body.category === "undefined") 
                req.body.category = [];
            else req.body.category = new Array(req.body.category);
        }
        next();
   },

// Validate fields.
body("name", "Name must not be empty.")
.isLength({ min: 1 })
.trim(),
body("description", "Description must not be empty.")
.isLength({ min: 1 })
.trim(),
body("price", "Price must not be empty.")
.isLength({ min: 1 })
.trim(),
body("num_in_stock", "Number in stock must not be empty")
.isLength({ min: 1 })
.trim(),

// Sanitize fields.
sanitizeBody("*").escape(),
sanitizeBody("category.*").escape(),
// Process request after validation and sanitization.
(req, res, next) => {
  // Extract the validation errors from a request.
  const errors = validationResult(req);

  // Create a Items object with escaped and trimmed data.
  var items = new Items({
    name: req.body.name,
    description: req.body.description,
    category: req.body.category,
    price: req.body.price,
    num_in_stock: req.body.num_in_stock
  });

  if (!errors.isEmpty()) {
    /* There are errors. Render form again with sanitized values/error messages.*/

  // Get all categories for form.
  async.parallel(
    {
      category: function(callback) {
        Category.find(callback);
      }
    },
    function(err, results) {
      if (err) {
        return next(err);
      }

      res.render("items_form", {
        title: "Create Item",
        category: results.category,
        items: items,
        errors: errors.array()
      });
    }
  );
  return;
} else {
  // Data from form is valid. Save book.
  items.save(function(err) {
    if (err) {
      return next(err);
    }
    // Successful - redirect to new items record.
    res.redirect(items.url);
  });
}
}
];

---

//items.js(Model):
var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var ItemsSchema = new Schema ({
name: {type: String, required: true, max: 100},
description: {type: String, required: true},
category: {type: Schema.Types.ObjectId, ref: 'Category', required: true},
price: {type: String, required: true},
num_in_stock: {type: String, required: true}
})

ItemsSchema.virtual('url').get(function() {
     return '/catalog/items/' + this._id
});

module.exports = mongoose.model('Items', ItemsSchema);

---

//catalog.js (Router):

router.get('/items/create', items_controller.items_create_get);
router.post('/items/create', items_controller.items_create_post);

---

//items_form.pug(views):

extends layout

block content
    h1= title

    form(method='POST' action='')
        div.form-group
            label(for='name') Name:
            input#name.form-control(type='text', placeholder='Name of item' name='name' required='true' value=(undefined===items ? '' : items.name) )
        div.form-group
             label(for='description') Description:
             input#description.form-control(type='textarea', placeholder='Enter Description' name='description' value=(undefined===items ? '' : items.description) required='true' )
        div.form-group
            label(for='category') Category:
            input#category.form-control(type='text', placeholder='Consumable, Tools or Accessories' name='category' value=(undefined===items ? '' : items.category.name) required='true' )
        div.form-group
            label(for='price') Price:
            input#price.form-control(type='text', placeholder='Price: e.g. 20$' name='price' value=(undefined===items ? '' : items.price) required='true')
        div.form-group
            label(for='num_in_stock') Number in Stock:
            input#num_in_stock.form-control(type='text', placeholder='num in stock: e.g. 2' name='num_in_stock' value=(undefined===items ? '' : items.num_in_stock) required='true') 
        button.btn.btn-primary(type='submit') Submit 

    if errors 
        ul
            for error in errors
                li!= error.msg

---

//Edit: catalog.js (Router):
// GET catalog home page.
router.get('/', items_controller.index);
// GET request for one Item.
router.get('/items/:id', items_controller.items_detail);
// GET request for list of all Item.
router.get('/items', items_controller.items_list);
router.get('/items/create', items_controller.items_create_get);
router.post('/items/create', items_controller.items_create_post);
// GET request to delete Item.
router.get('/items/:id/delete', items_controller.items_delete_get);
// POST request to delete Item.
router.post('/items/:id/delete',
items_controller.items_delete_post);
// GET request to update Item.
router.get('/items/:id/update', items_controller.items_update_get);
// POST request to update Item.
router.post('/items/:id/update',
items_controller.items_update_post);

---

this problem is also in my category model as well...

the output screen is fine and all the other CRUD views work other than the create controller... Maybe it's worth mentioning that when I update my items my items_form.js works perfectly! */

Answer 1

The problem is with your virtual in schema, try changing it to:

ItemsSchema.virtual('url').get(function() {
     return '/catalog/items/' + this._id.toString()
});

That is because the _id is of type ObjectId and you are trying to concat it with string.

Hope this helps :)

Answer 2

Because you putting:

router.get('/items/:id', items_controller.items_detail);

Before:

router.get('/items/create', items_controller.items_create_get);

So when you call /items/create , the router will point to items_controller.items_detail , not items_controller.items_create_get and get create as the param id .

Change your router to put /items/:id after /items/create may solve your problem.