Init

helpers/functions/embedding.go

@@ -0,0 +1,93 @@
+package functions
+
+import (
+	"html/template"
+	"io"
+	"io/fs"
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+type Embedder struct {
+	embed_cache sync.Map
+	fs          fs.FS
+}
+
+func NewEmbedder(fs fs.FS) *Embedder {
+	return &Embedder{
+		fs:          fs,
+		embed_cache: sync.Map{},
+	}
+}
+
+// INFO: We initialize the cache in both functions, which is only valid if both of these get
+// called in the same context, eg. when creating a template engine.
+func (e *Embedder) EmbedSafe() func(string) template.HTML {
+	return func(path string) template.HTML {
+		path = strings.TrimSpace(path)
+		path = filepath.Clean(path)
+		val, err := e.getFileData(path)
+		if err != nil {
+			return template.HTML("")
+		}
+
+		return template.HTML(val)
+	}
+}
+
+func (e *Embedder) Embed() func(string) string {
+	return func(path string) string {
+		path = strings.TrimSpace(path)
+		path = filepath.Clean(path)
+		val, err := e.getFileData(path)
+		if err != nil {
+			return ""
+		}
+
+		return string(val)
+	}
+}
+
+func (e *Embedder) getFileData(path string) ([]byte, error) {
+	if val, ok := e.embed_cache.Load(path); ok {
+		return val.([]byte), nil
+	}
+
+	f, err := e.fs.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	data, err := io.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+
+	e.embed_cache.Store(path, data)
+	return data, nil
+}
+
+func (e *Embedder) EmbedXSLT() func(string) template.HTML {
+	return func(path string) template.HTML {
+		path = strings.TrimSpace(path)
+		path = filepath.Clean(path)
+		fn := filepath.Base(path)
+		ext := filepath.Ext(fn)
+		fn = fn[:len(fn)-len(ext)]
+
+		if (ext != ".xsl" && ext != ".xslt") || ext == "" || fn == "" {
+			return template.HTML("[ERROR: " + "file is not an XSLT file" + "]")
+		}
+
+		val, err := e.getFileData(path)
+		if err != nil {
+			return template.HTML("[ERROR: " + err.Error() + "]")
+		}
+
+		src := "<script id=\"" + fn + "\" type=\"application/xml\">\n" + string(val) + "\n</script>"
+
+		return template.HTML(src)
+	}
+}