Web interface assets are sent with incorrect Content-Type header

[joschi]

Problem description

Steps to reproduce the problem

1. Start Graylog.
2. Open web interface in Internet Explorer 9 or later.
3. See web interface fail to load.

Related mailing list thread: https://groups.google.com/forum/#!topic/graylog2/Kp-smupTq70
Related MSDN article: https://msdn.microsoft.com/en-us/library/gg622941(v=vs.85).aspx

The web interface currently always uses the content type application/octet-stream for assets which IE 9 and later refuses to load due to the MIME type mismatch.

$ curl -I 'http://localhost:9000/vendor.js'
HTTP/1.1 200 OK
ETag: "df53558427f19224afbc2e7ebdadf0992b9419eddbd25a43ea3b2fbbdac47021"
Cache-Control: no-transform, max-age=31536000
Last-Modified: Tue, 29 Mar 2016 07:40:09 GMT
X-Graylog-Node-ID: cd03ee44-b2a7-4824-be16-bb7456149dbd
Vary: Accept-Encoding
Content-Length: 0
Content-Type: application/octet-stream
Date: Tue, 29 Mar 2016 07:54:55 GMT

$ curl -I --compressed 'http://localhost:9000/vendor.js'
HTTP/1.1 200 OK
ETag: "df53558427f19224afbc2e7ebdadf0992b9419eddbd25a43ea3b2fbbdac47021"
Cache-Control: no-transform, max-age=31536000
Last-Modified: Tue, 29 Mar 2016 07:40:09 GMT
X-Graylog-Node-ID: cd03ee44-b2a7-4824-be16-bb7456149dbd
Vary: Accept-Encoding
Content-Encoding: gzip
Content-Length: 0
Content-Type: application/octet-stream
Date: Tue, 29 Mar 2016 07:52:40 GMT

Environment

• Graylog Version: Graylog 2.0.0-beta.1
• Browser version: