added theme loader

backend/theme.go

@@ -0,0 +1,92 @@
+package main
+
+/*
+ The theme provides a method for adding customized CSS
+ or Javascript to Alice:
+
+ A theme directory can be specified in the config.
+ Stylesheets and Javascript residing in the theme root
+ directory will be included in the frontends HTML.
+
+ Additional files can be added in subdirectories.
+ These are served aswell and can be used for additional
+ assets. (E.g. a logo)
+*/
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"io/ioutil"
+	"net/http"
+)
+
+type Theme struct {
+	Config ThemeConfig
+}
+
+func NewTheme(config ThemeConfig) (*Theme, error) {
+	theme := &Theme{
+		Config: config,
+	}
+
+	// Check if the the path is present and readable
+	path := theme.Config.Path
+	if _, err := os.Stat(path); err != nil {
+		return nil, fmt.Errorf("Theme path could not be found: %s", path)
+	}
+
+	return theme, nil
+}
+
+/*
+ Get includable files from theme directory
+*/
+func (self *Theme) listIncludes(suffix string) []string {
+	includes := []string{}
+
+	files, err := ioutil.ReadDir(self.Config.Path)
+	if err != nil {
+		return []string{}
+	}
+
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+
+		if strings.HasSuffix(file.Name(), suffix) {
+			include := self.Config.BasePath + "/" + file.Name()
+			includes = append(includes, include)
+		}
+	}
+
+	return includes
+}
+
+/*
+ Retrieve a list of includeable stylesheets
+*/
+func (self *Theme) Stylesheets() []string {
+	return self.listIncludes(".css")
+}
+
+/*
+ Retrieve a list of includeable javascipts
+*/
+func (self *Theme) Scripts() []string {
+	return self.listIncludes(".js")
+}
+
+func (self *Theme) Handler() http.Handler {
+	log.Println("Using theme at:", self.Config.Path)
+
+	// Serve the content using the file server
+	path := self.Config.Path
+	themeFilesHandler := http.StripPrefix(
+		self.Config.BasePath, http.FileServer(http.Dir(path)))
+
+	return themeFilesHandler
+}