Mainly this was a change to helpers.MakePermalink, but to get the local server to run correctly,
we needed to redirect the path of the request from /foo to /. In addition, I added tests for the
server's code for fixing up the base url with different config file & CLI options.
git bisect identified 62dd1d4 as the breaking commit; when
github.com/spf13/viper was introduced, the Params field was always
empty.
Given a map in YAML in Viper, the return type is
`map[interface{}]interface{}`, _not_ `map[string]interface{}`, even if
`.SetDefault()` has been called with an item of
`map[string]interface{}{}` so the cast assertion on the `.Get("Params")`
always failed.
Viper stores Permalinks as a map[string]interface{}, so the type assertion
to PermalinkOverrides (map[string]PathPattern) will always fail.
We can, however, get Permalinks as a map[string]string, and convert each
value to a PathPattern.
If you don't have access to the root domain of your site (eg a GitHub project
page) and you try to generate custom permalinks, they must begin with a slash.
Go's URL resolution library sees the leading slash and thinks "this URL starts
at the root", just like a filesystem - so it discards your subdomain and maps
all custom permalinks from the root of your site. Fine if you control the root
domain, not so useful if you don't.
Removing the check for a leading slash fixes this problem. You can now specify
custom permalinks that do not start with a slash, and they will map safely
regardless of what subdomain you upload the generated site under.
Tests have been updated for this commit so that they continue to function.
