Node.js express.json middleware not parsing request as expected

Question

I have a simple cURL (i think this is right) that posts a small JSON object to my express server:

curl -d "{'test': 'this'}" localhost:3000/rest/user/authenticate

I have express set up as:

// set up body parsing in express  to be able  to get parse JSON posts
server.use(express.json());
server.use(express.urlencoded());

and have handler that accepts the route:

JSON = require('JSON')
module.exports = {
    authenticateUser: function create(req, res){
        var postedObject = req.body
        console.log(postedObject)
        res.send('Handle Post: authenticateUser');
    }
}

the handler is getting called, but it is logging the JSON body unexpectedly:

{ '{\'test\': \'this\'}': '' }

So my entire object looks to be the name side of a JSON Name:Value pair object. no matter what I post it seems to be appending the value side. Unless I do something like this:

curl -d "a=a" localhost:3000/rest/user/authenticate

which logs:

{'a':'a'}

so have i not set the right headers? Configured express wrong? I plan on digging through the express code, but wondered if somebody might know before I find the solution. Either way having a searchable/indexed answer to this on the web will be nice.

update 1

ok I need to add the header to the cURL

curl -H "Content-Type: application/json" -d "{'test': 'this'}" localhost:3000/rest/user/authenticate

which gives the error:

Parsing: {'test': 'this'}
SyntaxError: Unexpected token '
    at Object.parse (native)
    at C:\blah\node_modules\express\node_modules\connect\lib\middleware\json.js:86:19
        at IncomingMessage.onEnd (C:blah\node_modules\express\node_modules\connect\node_modules\raw-body\index.js:109:7)
        at IncomingMessage.g (events.js:180:16)
        at IncomingMessage.EventEmitter.emit (events.js:92:17)
        at _stream_readable.js:920:16
        at process._tickCallback (node.js:415:13)

OR curl -H "Content-Type: application/json" -d "{test: 'this'}" localhost:3000/rest/user/authenticate

which gives the error:

Parsing: {test: 'this'}
SyntaxError: Unexpected token t
    at Object.parse (native)
    at C:\blah\node_modules\express\node_modules\connect\lib\middleware\json.js:86:19
        at IncomingMessage.onEnd (C:blah\node_modules\express\node_modules\connect\node_modules\raw-body\index.js:109:7)
        at IncomingMessage.g (events.js:180:16)
        at IncomingMessage.EventEmitter.emit (events.js:92:17)
        at _stream_readable.js:920:16
        at process._tickCallback (node.js:415:13)

update 2

in the file connect/lib/middleware/json.js

this line seems to be the one causing issues

req.body = JSON.parse(buf, options.reviver);

update 3

I really think it is my cURL

buf= JSON.stringify({test: 'This'});
console.log(buf)
req.body = JSON.parse(buf, options.reviver);

works logging first {"test":"this"}

and then in my handler:

----------------------
{ test: 'this' }
----------------------

Answer 1

1) JSON middleware only works if the request has Content-Type: application/json header.
2) Valid JSON should contain ", not '.
So it should be '{"test": "this"}' instead of "{'test': 'this'}"

Try this command:

curl -d '{"test": "this"}' -H "Content-Type: application/json" localhost:3000/rest/user/authenticate

Answer 2

THe answer has two pieces

1. add the content header

2. on windows go through the pain of passing the json correctly, cURL on my windows machine doesn't deal with interchanging the single and double quotes , therefore the proper cURL is

   curl -H "Content-Type: application/json" -d "{"""test""": """this"""}" localhost:3000/rest/user/authenticate

Yup, inside of the data parameter, you need to use three double quotes to send a single double quote to the server.

Accepting zub's answer, because he is correct. I was trying a bunch of things to get around windows here.