Serve folders of Markdown to different domains over HTTP, [Spartan](https://portal.mozz.us/gemini/spartan.mozz.us/) and [Nex](https://nightfall.city/nex/info/specification.txt), rendered on the fly with no build step.
A Rust re-implementation of [smolweb](https://code.randogoth.com/randogoth/smolweb), which serves one folder from one process with its output formats hardcoded and its configuration in per-file frontmatter. itsybitsy changes all three: one process serves many domains, each output format is a separate crate behind a cargo feature, and configuration lives in a TOML file per content directory.
Two files. A server file names the virtual hosts and the listeners:
```toml
version = 1
[site.smol]
root = "/srv/smol/content"
hosts = ["smol.place", "www.smol.place"]
[listener.web]
protocol = "http"
bind = "0.0.0.0:8080"
formats = ["xhtmlmp", "html"]
default_site = "smol"
```
A `.itsybitsy.toml` in any content directory says how the Markdown in **that directory** renders. There is no inheritance: a subdirectory without its own file uses the built-in defaults rather than its parent's. Repetition in a deep tree is the price of never having to look elsewhere to know how a page renders.
`[defaults]` applies to every Markdown file in the directory; a `[page."name.md"]` table overrides it for one file. `title` is per-page by nature, so setting it in `[defaults]` is an error; left unset, it is derived from the page's first level-1 heading. Each renderer's own keys arrive with that renderer. Editing the file re-renders that directory's pages on the next request, and a file that fails to parse makes them error rather than silently falling back to defaults.
Because the name begins with a dot, the same rule that keeps `.secret.md` out of the URL space keeps this file out of it too.
`--check` validates the configuration and reports the routing it resolved, without binding a port:
```console
$ itsybitsy --config /etc/itsybitsy.toml --check
sites:
smol: /srv/smol/content
hosts:
smol.place -> smol
www.smol.place -> smol
listeners:
web: http on 0.0.0.0:8080 [xhtmlmp, html] by host, default smol
formats rendered per page: html, xhtmlmp
```
Everything the schema cannot express is checked here rather than on first request: a format no enabled feature provides, two sites claiming one hostname, a content root that does not exist, a server file sitting inside a content root where it would be served.
Links should be root-relative and extensionless (`[about](/about)`, not `about.md`), so the same link resolves identically from every protocol.
| Request | Serves |
| --- | --- |
| `/` | `index.md` |
| `/foo` | `foo.md`, else `foo/index.md` |
| `/foo.md` | redirects to `/foo` |
| `/img.png` | the file itself, by media type |
Nothing outside the content root is reachable. A request target is percent-decoded before it is normalised, so an encoded `..` becomes a real one and gets clamped at the root rather than quietly matching nothing; any path component beginning with a dot is refused outright; and whatever survives is canonicalised and required to still be inside the root, which is what defeats a symlink pointing out of it. There are no generated directory listings — only `index.md`.
