Feature: URL base/URL subpath support

[Shihira]

As discussed in issue #163 , the base URL feature is required to host silverbullet through reverse proxy without the need of subdomain, enabling the usage of some port proxy such as ngrok.

In this implementation, the url prefix is read from environment variable SB_URL_PREFIX, and passed to the client by text substitutions in index.html.

I did many coarse batch substitution in like http_sever.ts without fine tests, so it might need to be carefully looked into.

[Shihira]

@zefhemel lint problems should be fixed in the appended commit. Restart the check will you please?

[zefhemel]

Good start, testing this right now let me post my findings:

1. While clicking page links works, the URL they appear to link to is still on the root (note the URL when you hover over them), likely you'll have to adapt cm_plugins/wiki_link.ts too.

[zefhemel]

I noticed that I have to prefix my prefix with a / otherwise it doesn't work (I tried SB_URL_PREFIX with website but then found only /website works). This ok, although it may be nice to sanitize this (just add a / if it's not there already)

[zefhemel]

When I transclude an image or PDF, it renders nicely inline, but when I click the transclusion link it links me to a 404. For instance:

but clicking that link:

[zefhemel]

Using the Navigate: To URL command, injects the url prefix even in external URLs:

{[Navigate: To URL|Community]("https://community.silverbullet.md")}

Sends me to https://community.silverbullet.md/website/ (/website is my configured prefix)

[zefhemel]

Sync mode doesn't seem to work at all (try switching to it by using the Sync button at the top right). And after being in Sync mode, disabling it breaks everything until I manually unregister the service worker.

[Shihira]

It seems there is still a long way to go before completely usable. Do I need to work on this alone or the project members will also provide assistance?

[Shihira]

I think I am doing it wrong. In most cases urls need to remain relative instead of getting a prefix injection everywhere. I will look into it by weekend.

[Shihira]

@zefhemel the latest commit fixes most of the url jumping problems you metioned earlier. And the sync mode appeared to function out of box after I applied the latest upstream update (without any modifications on my end).

[zefhemel]

Just did a bit more testing and many of the issues I reported remain. Do you need help? I can probably take this over, can't promise immediately though.

[Shihira]

Yes please take over