server.js

var express = require ('express');
var app = express();
var bodyParser = require('body-parser');

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/blogfall2017', {
  useMongoClient: true,
});

var PostSchema = mongoose.Schema({
    title: {type: String, required: true},
    body: String,
    tag: {type: String, enum: ['POLITICS','ECONOMY','EDUCATION']},
    posted: {type: Date, default: Date.now}
}, {collection: 'post'});

var PostModel = mongoose.model("PostModel", PostSchema);

//GET /style.css etc
app.use(express.static(__dirname + "/public"));
app.use(bodyParser.json()); //for parsing application/json
app.use(bodyParser.urlencoded({extended: true}));//for parsing application/x-www-form-urlencoded

app.post("/api/blogpost", createPost);
app.get("/api/blogpost", getAllPosts);
app.get("/api/blogpost/:id", getPostById);
app.delete("/api/blogpost/:id", deletePost);
app.put("/api/blogpost/:id", updatePost);

function updatePost(req, res){
  var postId = req.params.id;
  var post = req.body;
  PostModel
        .update({_id: postId}),{
          title: post.title,
          body: post.body
        })
        .then(
          function(status){
            res.sendStatus(200);
          },
          function(err){
            res.sendStatus(400);
          }
        );
}

function getPostById(req, res){
  var postId = req.params.id;
  PostModel
        .findById(postId)
        .then(
            function (post){
              res.json(post);
            },
            function (err){
              res.sendStatus(400);
            }
        );
}
function deletePost(req, res) {
  var postId = req.params.id;
  PostModel
        .remove({_id: postId});
         then(
          function (status) {
            res.sendStatus(200);
          },
          function () {
            res.sendStatus(400);
          }
        );

}

function getAllPosts(req, res) {
    PostModel
        .find()
        .then(
            function (posts) {
                res.json(posts);
            },
            function (err) {
                res.sendStatus(400);
            }
        );
}

function createPost (req,res){
    var post = req.body;
    console.log(post);
    PostModel
            .create(post)
            .then(
                function(postObj) {
                   res.json(200);
                },
                function (error) {
                   res.sendStatus(400);
                }
            );
}


app.listen(3000);