Node Express - 无法 POST / 错误

Question

I have been following a tutorial on how to build a full stack MEAN application and everything has been functioning fine up until this point (registration, login and authentication.)

I'm now trying to do a post request for the blog page and am receiving the following error:

<pre>Cannot POST /blogs/newBlog</pre>

All that I've done so far is create a schema, a route and then made the relevant changes to index.js. The schema file provided below is the one provided by the author of the tutorial in his respository (unlike the other two files it is in it's completed form.) The problem still persists and so I do not believe it to be the problem.

Blog schema:

/* ===================
   Import Node Modules
=================== */
const mongoose = require('mongoose'); // Node Tool for MongoDB
mongoose.Promise = global.Promise; // Configure Mongoose Promises
const Schema = mongoose.Schema; // Import Schema from Mongoose

// Validate Function to check blog title length
let titleLengthChecker = (title) => {
  // Check if blog title exists
  if (!title) {
    return false; // Return error
  } else {
    // Check the length of title
    if (title.length < 5 || title.length > 50) {
      return false; // Return error if not within proper length
    } else {
      return true; // Return as valid title
    }
  }
};

// Validate Function to check if valid title format
let alphaNumericTitleChecker = (title) => {
  // Check if title exists
  if (!title) {
    return false; // Return error
  } else {
    // Regular expression to test for a valid title
    const regExp = new RegExp(/^[a-zA-Z0-9 ]+$/);
    return regExp.test(title); // Return regular expression test results (true or false)
  }
};

// Array of Title Validators
const titleValidators = [
  // First Title Validator
  {
    validator: titleLengthChecker,
    message: 'Title must be more than 5 characters but no more than 50'
  },
  // Second Title Validator
  {
    validator: alphaNumericTitleChecker,
    message: 'Title must be alphanumeric'
  }
];

// Validate Function to check body length
let bodyLengthChecker = (body) => {
  // Check if body exists
  if (!body) {
    return false; // Return error
  } else {
    // Check length of body
    if (body.length < 5 || body.length > 500) {
      return false; // Return error if does not meet length requirement
    } else {
      return true; // Return as valid body
    }
  }
};

// Array of Body validators
const bodyValidators = [
  // First Body validator
  {
    validator: bodyLengthChecker,
    message: 'Body must be more than 5 characters but no more than 500.'
  }
];

// Validate Function to check comment length
let commentLengthChecker = (comment) => {
  // Check if comment exists
  if (!comment[0]) {
    return false; // Return error
  } else {
    // Check comment length
    if (comment[0].length < 1 || comment[0].length > 200) {
      return false; // Return error if comment length requirement is not met
    } else {
      return true; // Return comment as valid
    }
  }
};

// Array of Comment validators
const commentValidators = [
  // First comment validator
  {
    validator: commentLengthChecker,
    message: 'Comments may not exceed 200 characters.'
  }
];

// Blog Model Definition
const blogSchema = new Schema({
  title: { type: String, required: true, validate: titleValidators },
  body: { type: String, required: true, validate: bodyValidators },
  createdBy: { type: String },
  createdAt: { type: Date, default: Date.now() },
  likes: { type: Number, default: 0 },
  likedBy: { type: Array },
  dislikes: { type: Number, default: 0 },
  dislikedBy: { type: Array },
  comments: [{
    comment: { type: String, validate: commentValidators },
    commentator: { type: String }
  }]
});

// Export Module/Schema
module.exports = mongoose.model('Blog', blogSchema);

routes/blogs.js

const User = require('../models/user'); // Import User Model Schema
const jwt = require('jsonwebtoken');
const config = require('../config/database');

module.exports = (router) => {

  router.post('/newBlog', (req, res) => { // TODO: change URL
    res.send('test worked');
  });

  return router; // Return router object to main index.js
}

index.js

/* ===================
   Import Node Modules
=================== */
const env = require('./env');
const express = require('express');
const app = express();
const router = express.Router();
const mongoose = require('mongoose');
mongoose.Promise = global.Promise;
const config = require('./config/database');
const path = require('path');
const authentication = require('./routes/authentication')(router);
const blogs = require('./routes/blogs')(router);
const bodyParser = require('body-parser');
const cors = require('cors'); 

const port = process.env.PORT || 8080;

// Database Connection
mongoose.connect(config.uri, {
  useMongoClient: true,
}, (err) => {
  // Check if database was able to connect
  if (err) {
    console.log('Could NOT connect to database: ', err);
 message
  } else {
    console.log('Connected to ' + config.db);
  }
});

// Middleware
app.use(cors({ origin: 'http://localhost:4200' }));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
app.use(express.static(__dirname + '/public'));
app.use('/authentication', authentication);
app.use('/blogs', blogs);

app.get('*', (req, res) => {
  res.sendFile(path.join(__dirname + '/public/index.html'));
});

// Start Server: Listen on port 8080
app.listen(port, () => {
  console.log('Listening on port ' + port + ' in ' + process.env.NODE_ENV + ' mode');
});

I have been enjoying this course greatly and would appreciate any help (even if it is to simply rule out possible causes.)

Error in full:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Error</title>
</head>
<body>
<pre>Cannot POST /blogs/newBlog</pre>
</body>
</html>

Answer 1

Your problem has to do with:

app.use('/blogs', blogs);

The blogs function should be a function taking (req, res) but it actually takes (router) .

You have two options:

Create a router and pass into blogs , eg app.use('/blogs', blogs(router)); or

Add app.post() , eg

app.post('/blogs/newBlog', (req, res) => {
  res.send('test worked');
});

Answer 2

Check spelling of your route

In my case I was posting from a url that had a missing letter.

I was doing POST /webooks/ but I needed to do POST /webhooks (note the missing h letter).

So it may also be that you misspell your routes.

Answer 3

Just try to change from bodyparser to express means...

instead of

app.use(bodyParser.json())

use app.use(express.json())

Answer 4

Please replace this:

router.post('/newBlog', (req, res) => {
  res.send('test worked');
});

With this (on all your methods "get, post, use" etc):

// Make sure to always add a slash both before and after the endpoint!
router.post('/newBlog/', (req, res) => {
  res.send('test worked');
});

I encounter this issue mostly if I don't add endpoint slashes properly.