Allow plugins to provide their own templates

README.md

@@ -18,7 +18,7 @@ HTTP server at `themes/<name>/assets/*`.
 
 ## Plugins
 
-Lua plugins are supported. They can be dropped in `plugins/*.lua`.
+Lua plugins are supported. They can be dropped in `plugins/<name>/main.lua`.
 
 API:
 
@@ -28,6 +28,8 @@ API:
 * `koushin.set_route(method, path, f)`: register a new HTTP route, `f` will be
   called with the HTTP context
 
+Plugins can provide their own templates in `plugins/<name>/public/*.html`.
+
 ## Contributing
 
 Send patches [on the mailing list](https://lists.sr.ht/~sircmpwn/koushin),

plugin.go

@@ -6,9 +6,11 @@ import (
 	"github.com/labstack/echo/v4"
 )
 
+const pluginDir = "plugins"
+
 type Plugin interface {
 	Name() string
-	Filters() template.FuncMap
+	LoadTemplate(t *template.Template) error
 	SetRoutes(group *echo.Group)
 	Inject(name string, data interface{}) error
 	Close() error

plugin_lua.go

@@ -86,8 +86,20 @@ func (p *luaPlugin) Inject(name string, data interface{}) error {
 	return nil
 }
 
-func (p *luaPlugin) Filters() template.FuncMap {
-	return p.filters
+func (p *luaPlugin) LoadTemplate(t *template.Template) error {
+	t.Funcs(p.filters)
+
+	paths, err := filepath.Glob(filepath.Dir(p.filename) + "/public/*.html")
+	if err != nil {
+		return err
+	}
+	if len(paths) > 0 {
+		if _, err := t.ParseFiles(paths...); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 func (p *luaPlugin) SetRoutes(group *echo.Group) {
@@ -136,7 +148,7 @@ func loadLuaPlugin(filename string) (*luaPlugin, error) {
 }
 
 func loadAllLuaPlugins(log echo.Logger) ([]Plugin, error) {
-	filenames, err := filepath.Glob("plugins/*.lua")
+	filenames, err := filepath.Glob(pluginDir + "/*/main.lua")
 	if err != nil {
 		return nil, fmt.Errorf("filepath.Glob failed: %v", err)
 	}

template.go

@@ -92,15 +92,18 @@ func loadTemplates(logger echo.Logger, defaultTheme string, plugins []Plugin) (*
 			return url.PathEscape(s)
 		},
 	})
-	for _, p := range plugins {
-		base = base.Funcs(p.Filters())
-	}
 
 	base, err := base.ParseGlob("public/*.html")
 	if err != nil {
 		return nil, err
 	}
 
+	for _, p := range plugins {
+		if err := p.LoadTemplate(base); err != nil {
+			return nil, fmt.Errorf("failed to load template for plugin '%v': %v", p.Name(), err)
+		}
+	}
+
 	themes := make(map[string]*template.Template)
 
 	files, err := ioutil.ReadDir(themesDir)