When following link from outside world directly to campsite detail page get 404 for a long time

[mlandauer]

Now that we have Google indexing https://thatscamping.org it's very likely that a person who's never visited the site before will go directly to a campsite detail page.

Their current experience is:

• Briefly see content for the website
• Replaced by 404
• If they wait around long enough the data will get loaded and they'll see the campsite content again

Obviously a terrible experience.

What would be better is if on a campsite detail page, the campsite data gets loaded as soon as possible. A few different ways that we could do this:

1. After elm has taken control: Directly load the campsite data from the remote database. Then allow the synching of the databases to take over.
   • Advantage: Simple and not adding more code on the javascript side
   • Disadvantage: We get a flash of 404 (or loading)
2. Before elm has taken control: See that we're on a campsite detail page and directly load the campsite from the remote database. Then, hand over to elm.
   • Advantage: There will no 404 (or loading) visible to the user at all.
   • Disadvantage: We need to have logic to recognise routes on the javascript side.
3. Before elm has taken control: If there is no local database, then load all the campsites directly from the remote database. Then, hand over to elm.
   • Advantage: Simple and no flash of 404 for the user.
   • Disadvantage: Slower than option 2

[mlandauer]

Another option is for the server to send back to the client (alongside the static html), a command or indication of what data the client needs to load.

[mlandauer]

Related to #85

[mlandauer]

Implemented option 3 in fed4b58. Let's see how that works in practise before deciding whether that's good enough and whether to close this ticket.