Implement per-host templates

Fixes #7.

Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>

docs/content/configuration/templating.md

@@ -3,7 +3,9 @@ title: Templating
 description: Changing the Iocaine template
 ---
 
-`iocaine` uses [Handlebars](https://handlebarsjs.com/) for templating, and uses only a single template, `main`. See the Handlebars for basic syntax. A [default template][template:Default] is provided, but if you want to change it, you can configure a [template directory](@/configuration/index.md#templates), and place a customized `main.hbs` file in it, and `iocane` will use that over the default.
+`iocaine` uses [Handlebars](https://handlebarsjs.com/) for templating, and will look for a template named `hosts/$host.hbs` (where `$host` is whatever is in the hosts header), but fall back on `main`, if a host-specific template is not found.
+
+See the Handlebars for basic syntax. A [default template][template:Default] is provided, but if you want to change it, you can configure a [template directory](@/configuration/index.md#templates), and place a customized `main.hbs` file in it, and `iocane` will use that over the default. Naturally, you can also place host-specific templates in a `hosts/` subdirectory.
 
  [template:default]: https://git.madhouse-project.org/algernon/iocaine/src/branch/main/templates/main.hbs
 

src/assembled_statistical_sequences.rs

@@ -144,6 +144,11 @@ impl AssembledStatisticalSequences {
             links,
         };
 
+        let host_template = &format!("hosts/{}", host);
+        if handlebars.has_template(host_template) {
+            handlebars.render(host_template, &data).unwrap()
+        } else {
             handlebars.render("main", &data).unwrap()
         }
     }
+}