Setting custom response header in plain Node.js

Question

My situation of using Node.js is like this:

Client --> Node.js --> External Rest API

So, vice-versa will be the response. As per requirement, I need to capture response headers from External Rest API and append it to Node.js's response header and to a client I need to send it as a single response header. To which I tried like this (this header is from Node.js side):

var resHeaders = {
                    'Content-Type': 'application/json',
                    'Access-Control-Allow-Origin': '*',
                    'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE',
                    'Access-Control-Allow-Headers': 'Content-Type,Last-modified,Connection,Access-Control-Allow-Origin,Access-Control-Allow-Methods,Date',
                     'Access-Control-Expose-Headers': 'Content-Type,Last-modified,Connection,Access-Control-Allow-Origin,Access-Control-Allow-Methods,Date'
                 };

I am getting External API's response header in a variable like this:

var curlHeadersResp; //I am executing curl to get response headers

Finally I am trying to combile both like this:

var finalRespHeaders = new Array();
finalRespHeaders.push(curlHeadersResp);
finalRespHeaders.push(JSON.stringify(resHeaders));

res.writeHead(200, JSON.stringify(finalRespHeaders));

But the response header I am getting is in junk like this:

HTTP/1.1 200 ["HTTP/1.1 200 OK\r\nServer: Apache-Coyote/1.1\r\nContent-Type: application/json\r\nTransfer-Encoding: chunked\r\nDate: Mon, 03 Feb 2014 09:25:06 GMT\r\n\r\n","{\"Content-Type\":\"application/json\",\"Access-Control-Allow-Origin\":\"*\",\"Access-Control-Allow-Methods\":\"GET,PUT,POST,DELETE\",\"Access-Control-Allow-Headers\":\"Content-Type,Last-modified,Connection,Access-Control-Allow-Origin,Access-Control-Allow-Methods,Date\",\"Access-Control-Expose-Headers\":\"Content-Type,Last-modified,Connection,Access-Control-Allow-Origin,Access-Control-Allow-Methods,Date\"}"] Date: Mon, 03 Feb 2014 09:25:38 GMT

I think it is a problem of concatination. My question is if anyone has any idea of generating dynamic headers or anyone could shed some light on this it would be very helpful.

Why I am doing like this? Because of cross-domain requests problems, so I don't have control on external server. So from my Node.js side I need to append Allow cross domain headers so that cross domain requests are possible.

According to Node.js http Docs, you should pass headers as an object, while you're passing a JSON string. — Leonid Beschastny
– Leonid Beschastny, Commented Feb 3, 2014 at 9:37
@LeonidBeschastny, yes I tried that, but just I am getting as [object Object] — Pradeep Simha
– Pradeep Simha, Commented Feb 3, 2014 at 9:51

micnic · Accepted Answer · 2014-02-03 09:54:18Z

0

From Node.JS Documentation:

//response.writeHead(statusCode, [reasonPhrase], [headers])
//                    number      string          object

var body = 'hello world';
response.writeHead(200, {
  'Content-Length': body.length,
  'Content-Type': 'text/plain' });

You don't need to create an array an push the objects to it, join together the curlHeadersResp and resHeaders:

Object.keys(curlHeadersResp).forEach(function (element) {
    resHeaders[element] = curlHeadersResp[element;
});

Where you write the header you don't need to stringify the object, just:

res.writeHead(200, resHeaders);

edited Feb 3, 2014 at 9:54

answered Feb 3, 2014 at 9:48

micnic

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5 Comments

Pradeep Simha Over a year ago

Yes I tried that, but just I am getting as [object Object]

micnic Over a year ago

Updated answer, check it out, you need to have in the end an Object! NOT a string or an array

Pradeep Simha Over a year ago

Ok, thanks I tried this, but now I am getting cannot call keys on non-object error. I think it's because curlHeadersRespI am getting in json string.

micnic Over a year ago

Yes, this may be the problem, parse it and try again

Pradeep Simha Over a year ago

Yes I tried, now I am getting these type of error, unexpected token H date=Mon Feb 03 2014 10:07:35 GMT+0000 (UTC)

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