Nodejs how to set content-type header for every request

Question

I would like to know how I can set the header "Content-Type": "application/json" for every nodejs express request that comes in.

I tried both of these lines but my calls are still failing if I don't add the header myself:

app.use(function(req, res, next) {
    req.header("Content-Type", "application/json");
    res.header("Content-Type", "application/json");
    next();
});

All of my requests are json, so I don't want the front end (Anguler) to send me this header every time if I can just set it myself from the server side.

Answer 1

Response object has to use .setHeader instead of .header:

app.use(function(req, res, next) {
    res.setHeader("Content-Type", "application/json");
    next();
});

doc.

Answer 2

To update the request headers please add below custom middleware before bodyparser

app.use(function (req, res, next) {
  req.headers['content-type'] = 'application/json';
  next();
});

If still not working check the case of 'content-type' sent by your client. Put the 'content-type' in the same case

Answer 3

res.writeHead(200, { "Content-Type": "application/json" });

Here you have to also specify status code, 200 means Status is OK, learn more about status codes here : HTTP Status Codes

or use this code

res.setHeader("Content-Type", "application/json");