unirest-nodejs .attach() path issues on Windows

1: Code with absolute path

var unirest = require('unirest')

var path = 'C:\\Temp\\test-data.txt'

unirest.post('http://httpbin.org/post')
	.attach('my-file', path)
	.end(function(res) {
		console.log(res.body)
	})

1: Output with absolute path

$ node gist.js

stream.js:94
      throw er; // Unhandled stream error in pipe.
            ^
Error: ENOENT, open 'c:\dev\temp\unirest-issue\node_modules\unirest\C:\Temp\test-data.txt'

2: Code with relative path

var unirest = require('unirest')

var path = 'test-data.txt'

unirest.post('http://httpbin.org/post')
	.attach('my-file', path)
	.end(function(res) {
		console.log(res.body)
	})

2: Output with relative path

$ node gist.js

stream.js:94
      throw er; // Unhandled stream error in pipe.
            ^
Error: ENOENT, open 'c:\dev\temp\unirest-issue\node_modules\unirest\test-data.txt'

3: Code with colon-slash-slash in the path

var unirest = require('unirest')

var path = 'C://Temp/test-data.txt'

unirest.post('http://httpbin.org/post')
	.attach('my-file', path)
	.end(function(res) {
		console.log(res.body)
	})

3: Output with colon-slash-slash in the path

$ node gist.js
Path with forward slashes
{ data: '',
  json: null,
  headers:
   { 'X-Bluecoat-Via': '(removed)',
     Connection: 'close',
     'Content-Type': 'multipart/form-data; boundary=--------------------------14
8007494553476287118800',
     Host: 'httpbin.org',
     'Transfer-Encoding': 'chunked',
     'X-Request-Id': 'b27077cb-c304-459c-9cfb-4f18ddca466e' },
  args: {},
  url: 'http://httpbin.org/post',
  origin: '(removed)',
  files: {},
  form: {} }
  
  (Despite "files: {}", watching the request with Fiddler showed the file being sent.  It doesn't show in requestb.in either.  Side note!)

4. Workaround

var unirest = require('unirest')
var path = require('path')

var relPath = path.relative('./node_modules/unirest', 'C:\\Temp\\test-data.txt')
console.log("Path we're going to use", relPath)

unirest.post('http://httpbin.org/post')
	.attach('my-file', relPath)
	.end(function(res) {
		console.log(res.body)
	})

4. Workaround explained

As paths are treated as relative to __dirname in Unirest, the input path needs to be modified to be relative to where unirest is installed.  This feels rather like a terrible hack...

4. Workaround output

$ node gist.js
Path we're going to use ..\..\..\..\..\Temp\test-data.txt
Response
{ data: '',
  origin: '15.219.169.71',
  json: null,
  form: {},
  url: 'http://httpbin.org/post',
  args: {},
  files: {},
  headers:
   { 'Transfer-Encoding': 'chunked',
     'X-Bluecoat-Via': 'a9f78fc983ea0416',
     'Content-Type': 'multipart/form-data; boundary=--------------------------28
0340137059443056370490',
     Connection: 'close',
     Host: 'httpbin.org',
     'X-Request-Id': '20dda8a6-6782-4c48-b5aa-8d0b6a0f53f3' } }

Explanation

I'm trying to upload a file using unirest-nodejs and an HTTP POST.  The documentation states that:
"If path contains http or https Request will handle it as a remote file, otherwise if it contains :// and not http or https it will consider it to be a direct file path. If no :// is found it will be considered a relative file path."

This doesn't seem to work for Windows (and I question whether it works for Linux either).

- If the path has http:// or https:// then we're fine (not demonstrated here)
- If the path is an absolute Windows path (e.g. C:\\Temp\\test-data.txt) then it's treated as relative to ./node_modules/unirest (see example 1)
- If the path is a relative path (e.g. test-data.txt) then it's treated as relative to ./node_modules/unirest (see example 2)
- If the path has ://, e.g C://Temp/test-data.txt (see example 3) then the request is made.

This is rather awkward for Windows users, as file paths don't have '://' in them.

Issue filed with unirest-node: Kong/unirest-nodejs#12