Error: invalid json with multer and body-parser

问题

I am currently using multer for multipart/form-data in node.js application alongside with body-parser.

I tried to POST form-data using POSTMAN, but it is getting this error.

Error: invalid json
    at parse (/Users/k/Documents/application/node_modules/body-parser/lib/types/json.js:79:15)
    at /Users/k/Documents/application/node_modules/body-parser/lib/read.js:102:18
    at IncomingMessage.onEnd (/Users/k/Documents/application/node_modules/body-parser/node_modules/raw-body/index.js:136:7)
    at IncomingMessage.g (events.js:199:16)
    at IncomingMessage.emit (events.js:104:17)
    at _stream_readable.js:908:16
    at process._tickDomainCallback (node.js:381:11)

This is how I added multer and body-parser in my server.js

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

var app = express();

app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
app.use(multer({ dest: './uploads/'}));

I think it is probably because multer is not working. When I remove body-parser and try again, it shows empty json for console.log(req.body) and console.log(req.files).

Note: body-parser version is 1.12.0 and multer version is 0.1.8.

回答1:

The problem is not that you have both libraries body-parser and multer. If you try to post with a browser extension like postman, please make sure Content-Type is multipart/form-data and not application/json in your request header.

来源：https://stackoverflow.com/questions/29006170/error-invalid-json-with-multer-and-body-parser