custom_headers.js

var common = require('../common');
var assert = common.assert;
var http = require('http');

var FormData = require(common.dir.lib + '/form_data');

var CRLF = '\r\n';

var testHeader = 'X-Test-Fake: 123';

var expectedLength;

// ^----- I assume this part is obvious


// creating new server to receive FormData's (test) submition
var server = http.createServer(function(req, res)
{
  // check that content-length header exists
  assert.ok( typeof req.headers['content-length'] !== 'undefined' );
  // check that it has expected length
  assert.equal(req.headers['content-length'], expectedLength);

  // return OK code back to FormData to allow it end the test
  res.writeHead(200);
  res.end('done');
});

// Wait for receiving server to start up (it takes time)
server.listen(common.port, function()
{
  // creating FormData instance
  var form = new FormData();

  // preparing custom options with custom header for test field
  var options = {
    header:
      // this is basically how per-field headers look like in multipart 
      CRLF + '--' + form.getBoundary() + CRLF +
      testHeader +
      CRLF + CRLF,

    // override content-length,
    // much lower than actual buffer size (1000)
    knownLength: 1
  };

  // generating 1000 elements array
  // to make a Buffer to use as test fields value
  // Note: naive approach
  var bufferData = [];
  for (var z = 0; z < 1000; z++) {
    bufferData.push(1);
  }
  var buffer = new Buffer(bufferData);

  // add test field to the FormData's instance
  form.append('my_buffer', buffer, options);

  // (available to req handler)
  // calculating length of the whole request body,
  // including per-field header, boundaries and number of CRLFs
  // (I don't remember why it's done this specific way) :)
  expectedLength = form._lastBoundary().length + form._overheadLength + options.knownLength;

  // do submit dance
  // tell FormData, to submit things to the server
  common.actions.submit(form, server);
});