Theme Errors should not crash the blog

[ErisDS]

Issue Summary

This is the second part, or follow up to #1964

No matter what happens in a theme, or how bad an error is, the blog should not crash, it should just show a 500 error page with details of the error.

Steps to Reproduce

• Add an invalid handlebars helper to a partial, such as {{http://my-ghost-blog.com}}
• Add an empty partial and include it in the default template

Technical details:

• Ghost Version: 0.4.0
• Mode: Production

[xuduo35]

The crash happens when res.render call express-hbs module. One way to catch this exception is:

    process.on('uncaughtException', function(err) {
      console.log(typeof err);
    });

But it's not friendly to user. I think Ghost can track all http connections, and send 500 error to them when this kind of exception happened.

There is a existed called 'domain' which is used to do this thing. You guys can try.

[ErisDS]

I have opened an issue and submitted a PR against express-hbs to fix this:

TryGhost/express-hbs#47

[mgutz]

I merged and add the template filename to the error. Try [email protected] from npm.