Serving (One-Off) Files Securely on Heroku

January 24, 2014

If you need to serve a file or two from your Heroku-based site with SSL, but don’t need to serve the whole thing that way, there’s an easy way to do it that piggybacks off of Heroku’s certificate. See Heroku’s SSL Endpoint documentation for directions.

My Problem

A few days ago I posted about using Gistdeck, with instructions for modified version. Just before I released them, I found that using my version of Gistdeck on a real Gist caused horrible Chrome warnings about site security. That’s because GitHub serves Gists via HTTPS, but my site was serving Gistdeck via plain old HTTP. So when I used the bookmarklet, I was loading non-secure data into a secure page. Boom, warnings galore!

Fortunately, I didn’t have to get my own certificate just to serve those two files (one JS, one CSS). Heroku lets me use their certificate, with one catch. It’s not really a “catch” so much as a “fact of life”…

Use Your “Real” Heroku App Address

Of course (it’s obvious), you can’t use Heroku’s certificate for your own domain! Try to serve something in the domain using Heroku’s SSL certificate. That’s saying “trust me, it looks like Heroku is serving it, but this bobgilmore guy really is. You totally believe that, right?”

To deal with it, use your Heroku app’s “real” app name when serving via HTTPS. So, while most of this blog is served from, the Gistdeck code is served, securely, from

Obviously you wouldn’t want to serve a lot of code this way, but for the occasional file or two it’s fine. As long as you don’t get into any cross-site scripting issues…

Tags: heroku
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