Handle redirects isomorphically

[jamieparkinson]

Redirects were not being followed when clicking a link (ie they required a refresh / getInitialProps) - this should fix that.

Apologies for the weird steps to reproduce but this is how I found it and I can't work out a simpler way:

• Do an images search for 'rats'
• Click the 3rd result, which says 'Tord Boyaux'
• Click on 'More about this work' - get a 500
• Refresh the page - redirect.

note: I know the link to the image is still broken, that's a pipeline issue that I'll take a look at next

The fetch API is quite strange in this respect, and whatever next gives us on the server doesn't appear to follow the spec. See:

• Cannot get next URL for redirect="manual" whatwg/fetch#763
• https://stackoverflow.com/questions/46004103/how-do-i-determine-the-status-code-of-a-fetch-request/46005718

[jamesgorrie]

Shouldn't this be exposed in the images API where we link to the merged work? Feels like exposing redirected URLs when we know they aren't is the wrong fix for this?

[jamieparkinson]

Yeah, that's the pipeline issue I'm referring to - this PR fixes inconsistent behaviour between following links and "fresh" page loads, and I will fix the underlying issue with that specific example next.

[jamesgorrie]

Nice catch, nice fix!