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package revel
import (
"fmt"
"html"
"html/template"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
"reflect"
"regexp"
"strconv"
"strings"
"time"
)
var ERROR_CLASS = "hasError"
// This object handles loading and parsing of templates.
// Everything below the application's views directory is treated as a template.
type TemplateLoader struct {
// This is the set of all templates under views
templateSet *template.Template
// If an error was encountered parsing the templates, it is stored here.
compileError *Error
// Paths to search for templates, in priority order.
paths []string
// Map from template name to the path from whence it was loaded.
templatePaths map[string]string
}
type Template interface {
Name() string
Content() []string
Render(wr io.Writer, arg interface{}) error
}
var invalidSlugPattern = regexp.MustCompile(`[^a-z0-9 _-]`)
var whiteSpacePattern = regexp.MustCompile(`\s+`)
var (
// The functions available for use in the templates.
TemplateFuncs = map[string]interface{}{
"url": ReverseUrl,
"eq": Equal,
"set": func(renderArgs map[string]interface{}, key string, value interface{}) template.HTML {
renderArgs[key] = value
return template.HTML("")
},
"append": func(renderArgs map[string]interface{}, key string, value interface{}) template.HTML {
if renderArgs[key] == nil {
renderArgs[key] = []interface{}{value}
} else {
renderArgs[key] = append(renderArgs[key].([]interface{}), value)
}
return template.HTML("")
},
"field": NewField,
"option": func(f *Field, val, label string) template.HTML {
selected := ""
if f.Flash() == val {
selected = " selected"
}
return template.HTML(fmt.Sprintf(`<option value="%s"%s>%s</option>`,
html.EscapeString(val), selected, html.EscapeString(label)))
},
"radio": func(f *Field, val string) template.HTML {
checked := ""
if f.Flash() == val {
checked = " checked"
}
return template.HTML(fmt.Sprintf(`<input type="radio" name="%s" value="%s"%s>`,
html.EscapeString(f.Name), html.EscapeString(val), checked))
},
"checkbox": func(f *Field, val string) template.HTML {
checked := ""
if f.Flash() == val {
checked = " checked"
}
return template.HTML(fmt.Sprintf(`<input type="checkbox" name="%s" value="%s"%s>`,
html.EscapeString(f.Name), html.EscapeString(val), checked))
},
// Pads the given string with &nbsp;'s up to the given width.
"pad": func(str string, width int) template.HTML {
if len(str) >= width {
return template.HTML(html.EscapeString(str))
}
return template.HTML(html.EscapeString(str) + strings.Repeat("&nbsp;", width-len(str)))
},
"errorClass": func(name string, renderArgs map[string]interface{}) template.HTML {
errorMap, ok := renderArgs["errors"].(map[string]*ValidationError)
if !ok || errorMap == nil {
WARN.Println("Called 'errorClass' without 'errors' in the render args.")
return template.HTML("")
}
valError, ok := errorMap[name]
if !ok || valError == nil {
return template.HTML("")
}
return template.HTML(ERROR_CLASS)
},
"msg": func(renderArgs map[string]interface{}, message string, args ...interface{}) template.HTML {
str, ok := renderArgs[CurrentLocaleRenderArg].(string)
if !ok {
return ""
}
return template.HTML(Message(str, message, args...))
},
// Replaces newlines with <br>
"nl2br": func(text string) template.HTML {
return template.HTML(strings.Replace(template.HTMLEscapeString(text), "\n", "<br>", -1))
},
// Skips sanitation on the parameter. Do not use with dynamic data.
"raw": func(text string) template.HTML {
return template.HTML(text)
},
// Pluralize, a helper for pluralizing words to correspond to data of dynamic length.
// items - a slice of items, or an integer indicating how many items there are.
// pluralOverrides - optional arguments specifying the output in the
// singular and plural cases. by default "" and "s"
"pluralize": func(items interface{}, pluralOverrides ...string) string {
singular, plural := "", "s"
if len(pluralOverrides) >= 1 {
singular = pluralOverrides[0]
if len(pluralOverrides) == 2 {
plural = pluralOverrides[1]
}
}
switch v := reflect.ValueOf(items); v.Kind() {
case reflect.Int:
if items.(int) != 1 {
return plural
}
case reflect.Slice:
if v.Len() != 1 {
return plural
}
default:
ERROR.Println("pluralize: unexpected type: ", v)
}
return singular
},
// Format a date according to the application's default date(time) format.
"date": func(date time.Time) string {
return date.Format(DateFormat)
},
"datetime": func(date time.Time) string {
return date.Format(DateTimeFormat)
},
"slug": Slug,
}
)
func NewTemplateLoader(paths []string) *TemplateLoader {
loader := &TemplateLoader{
paths: paths,
}
return loader
}
// This scans the views directory and parses all templates as Go Templates.
// If a template fails to parse, the error is set on the loader.
// (It's awkward to refresh a single Go Template)
func (loader *TemplateLoader) Refresh() *Error {
TRACE.Printf("Refreshing templates from %s", loader.paths)
loader.compileError = nil
loader.templatePaths = map[string]string{}
// Set the template delimiters for the project if present, then split into left
// and right delimiters around a space character
var splitDelims []string
if TemplateDelims != "" {
splitDelims = strings.Split(TemplateDelims, " ")
if len(splitDelims) != 2 {
log.Fatalln("app.conf: Incorrect format for template.delimiters")
}
}
// Walk through the template loader's paths and build up a template set.
var templateSet *template.Template = nil
for _, basePath := range loader.paths {
// Walk only returns an error if the template loader is completely unusable
// (namely, if one of the TemplateFuncs does not have an acceptable signature).
funcErr := filepath.Walk(basePath, func(path string, info os.FileInfo, err error) error {
if err != nil {
ERROR.Println("error walking templates:", err)
return nil
}
// Walk into watchable directories
if info.IsDir() {
if !loader.WatchDir(info) {
return filepath.SkipDir
}
return nil
}
// Only add watchable
if !loader.WatchFile(info.Name()) {
return nil
}
var fileStr string
// addTemplate allows the same template to be added multiple
// times with different template names.
addTemplate := func(templateName string) (err error) {
// Convert template names to use forward slashes, even on Windows.
if os.PathSeparator == '\\' {
templateName = strings.Replace(templateName, `\`, `/`, -1) // `
}
// If we already loaded a template of this name, skip it.
if _, ok := loader.templatePaths[templateName]; ok {
return nil
}
loader.templatePaths[templateName] = path
// Load the file if we haven't already
if fileStr == "" {
fileBytes, err := ioutil.ReadFile(path)
if err != nil {
ERROR.Println("Failed reading file:", path)
return nil
}
fileStr = string(fileBytes)
}
if templateSet == nil {
// Create the template set. This panics if any of the funcs do not
// conform to expectations, so we wrap it in a func and handle those
// panics by serving an error page.
var funcError *Error
func() {
defer func() {
if err := recover(); err != nil {
funcError = &Error{
Title: "Panic (Template Loader)",
Description: fmt.Sprintln(err),
}
}
}()
templateSet = template.New(templateName).Funcs(TemplateFuncs)
// If alternate delimiters set for the project, change them for this set
if splitDelims != nil && basePath == ViewsPath {
templateSet.Delims(splitDelims[0], splitDelims[1])
} else {
// Reset to default otherwise
templateSet.Delims("", "")
}
_, err = templateSet.Parse(fileStr)
}()
if funcError != nil {
return funcError
}
} else {
if splitDelims != nil && basePath == ViewsPath {
templateSet.Delims(splitDelims[0], splitDelims[1])
} else {
templateSet.Delims("", "")
}
_, err = templateSet.New(templateName).Parse(fileStr)
}
return err
}
templateName := path[len(basePath)+1:]
// Lower case the file name for case-insensitive matching
lowerCaseTemplateName := strings.ToLower(templateName)
err = addTemplate(templateName)
err = addTemplate(lowerCaseTemplateName)
// Store / report the first error encountered.
if err != nil && loader.compileError == nil {
_, line, description := parseTemplateError(err)
loader.compileError = &Error{
Title: "Template Compilation Error",
Path: templateName,
Description: description,
Line: line,
SourceLines: strings.Split(fileStr, "\n"),
}
ERROR.Printf("Template compilation error (In %s around line %d):\n%s",
templateName, line, description)
}
return nil
})
// If there was an error with the Funcs, set it and return immediately.
if funcErr != nil {
loader.compileError = funcErr.(*Error)
return loader.compileError
}
}
// Note: compileError may or may not be set.
loader.templateSet = templateSet
return loader.compileError
}
func (loader *TemplateLoader) WatchDir(info os.FileInfo) bool {
// Watch all directories, except the ones starting with a dot.
return !strings.HasPrefix(info.Name(), ".")
}
func (loader *TemplateLoader) WatchFile(basename string) bool {
// Watch all files, except the ones starting with a dot.
return !strings.HasPrefix(basename, ".")
}
// Parse the line, and description from an error message like:
// html/template:Application/Register.html:36: no such template "footer.html"
func parseTemplateError(err error) (templateName string, line int, description string) {
description = err.Error()
i := regexp.MustCompile(`:\d+:`).FindStringIndex(description)
if i != nil {
line, err = strconv.Atoi(description[i[0]+1 : i[1]-1])
if err != nil {
ERROR.Println("Failed to parse line number from error message:", err)
}
templateName = description[:i[0]]
if colon := strings.Index(templateName, ":"); colon != -1 {
templateName = templateName[colon+1:]
}
templateName = strings.TrimSpace(templateName)
description = description[i[1]+1:]
}
return templateName, line, description
}
// Return the Template with the given name. The name is the template's path
// relative to a template loader root.
//
// An Error is returned if there was any problem with any of the templates. (In
// this case, if a template is returned, it may still be usable.)
func (loader *TemplateLoader) Template(name string) (Template, error) {
// Lower case the file name to support case-insensitive matching
name = strings.ToLower(name)
// Look up and return the template.
tmpl := loader.templateSet.Lookup(name)
// This is necessary.
// If a nil loader.compileError is returned directly, a caller testing against
// nil will get the wrong result. Something to do with casting *Error to error.
var err error
if loader.compileError != nil {
err = loader.compileError
}
if tmpl == nil && err == nil {
return nil, fmt.Errorf("Template %s not found.", name)
}
return GoTemplate{tmpl, loader}, err
}
// Adapter for Go Templates.
type GoTemplate struct {
*template.Template
loader *TemplateLoader
}
// return a 'revel.Template' from Go's template.
func (gotmpl GoTemplate) Render(wr io.Writer, arg interface{}) error {
return gotmpl.Execute(wr, arg)
}
func (gotmpl GoTemplate) Content() []string {
content, _ := ReadLines(gotmpl.loader.templatePaths[gotmpl.Name()])
return content
}
/////////////////////
// Template functions
/////////////////////
// Return a url capable of invoking a given controller method:
// "Application.ShowApp 123" => "/app/123"
func ReverseUrl(args ...interface{}) (string, error) {
if len(args) == 0 {
return "", fmt.Errorf("no arguments provided to reverse route")
}
action := args[0].(string)
actionSplit := strings.Split(action, ".")
if len(actionSplit) != 2 {
return "", fmt.Errorf("reversing '%s', expected 'Controller.Action'", action)
}
// Look up the types.
var c Controller
if err := c.SetAction(actionSplit[0], actionSplit[1]); err != nil {
return "", fmt.Errorf("reversing %s: %s", action, err)
}
// Unbind the arguments.
argsByName := make(map[string]string)
for i, argValue := range args[1:] {
Unbind(argsByName, c.MethodType.Args[i].Name, argValue)
}
return MainRouter.Reverse(args[0].(string), argsByName).Url, nil
}
func Slug(text string) string {
separator := "-"
text = strings.ToLower(text)
text = invalidSlugPattern.ReplaceAllString(text, "")
text = whiteSpacePattern.ReplaceAllString(text, separator)
text = strings.Trim(text, separator)
return text
}