feat: e-mail templates (#1158)

* View definition added

* Get templates and texts from the database.

* Fill in texts in templates

* Fill in texts in templates

* Client API added

* Weekly backup

* Weekly backup

* Daily backup

* Weekly backup

* Tests added

* Corrections from merge branch

* Fixes from pull request review

internal/notification/templates/template.go

@@ -12,23 +12,21 @@ const (
 	templateFileName = "template.html"
 )
 
-func GetParsedTemplate(dir http.FileSystem, contentData interface{}) (string, error) {
-	template, err := ParseTemplateFile(dir, "", contentData)
+func GetParsedTemplate(mailhtml string, contentData interface{}) (string, error) {
+	template, err := ParseTemplateFile(mailhtml, contentData)
 	if err != nil {
 		return "", err
 	}
 	return ParseTemplateText(template, contentData)
 }
 
-func ParseTemplateFile(dir http.FileSystem, fileName string, data interface{}) (string, error) {
-	if fileName == "" {
-		fileName = templateFileName
-	}
-	template, err := readFile(dir, fileName)
+func ParseTemplateFile(mailhtml string, data interface{}) (string, error) {
+	tmpl, err := template.New("tmpl").Parse(mailhtml)
 	if err != nil {
 		return "", err
 	}
-	return parseTemplate(template, data)
+
+	return parseTemplate(tmpl, data)
 }
 
 func ParseTemplateText(text string, data interface{}) (string, error) {
@@ -63,3 +61,20 @@ func readFile(dir http.FileSystem, fileName string) (*template.Template, error)
 	}
 	return tmpl, nil
 }
+
+func readFileFromDatabase(dir http.FileSystem, fileName string) (*template.Template, error) {
+	f, err := dir.Open(templatesPath + "/" + fileName)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	content, err := ioutil.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+	tmpl, err := template.New(fileName).Parse(string(content))
+	if err != nil {
+		return nil, err
+	}
+	return tmpl, nil
+}