91 lines
1.8 KiB
Go
91 lines
1.8 KiB
Go
package template
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import (
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"fmt"
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"html/template"
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"io"
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"io/fs"
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"os"
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"path"
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"strings"
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)
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type Service struct {
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baseDir string
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cache map[string]*template.Template
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}
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func createFuncMap() template.FuncMap {
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funcMap := template.FuncMap{
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"dict": func(pairs ...any) (map[string]any, error) {
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if len(pairs)%2 != 0 {
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return nil, fmt.Errorf("dict requires an even number of arguments")
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}
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m := make(map[string]any)
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for i := 0; i < len(pairs); i += 2 {
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key, ok := pairs[i].(string)
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if !ok {
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return nil, fmt.Errorf("dict keys must be strings")
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}
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m[key] = pairs[i+1]
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}
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return m, nil
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},
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"default": func(fallback string, value any) any {
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if value == nil {
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return fallback
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}
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return value
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},
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}
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return funcMap
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}
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func NewService(uiDir string) (*Service, error) {
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cache := make(map[string]*template.Template)
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uiFS := os.DirFS(uiDir)
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funcMap := createFuncMap()
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err := fs.WalkDir(uiFS, "pages", func(filePath string, d fs.DirEntry, err error) error {
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if err != nil {
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return err
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}
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if d.IsDir() {
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return nil
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}
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if !strings.HasSuffix(filePath, ".html") {
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return nil
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}
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// Key by the relative path under pages/, e.g. "auth/signin.html".
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relPath := strings.TrimPrefix(filePath, "pages/")
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tmpl, err := template.New(path.Base(filePath)).Funcs(funcMap).ParseFS(uiFS, filePath, "layouts/*.html")
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if err != nil {
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return fmt.Errorf("can't parse filesystem: %w", err)
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}
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cache[relPath] = tmpl
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return nil
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})
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if err != nil {
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return nil, fmt.Errorf("can't walk 'pages' in '%s': %w", uiDir, err)
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}
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return &Service{
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baseDir: uiDir,
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cache: cache,
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}, nil
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}
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func (e *Service) Render(w io.Writer, pageName string, data any) error {
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tmpl, ok := e.cache[pageName]
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if !ok {
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return fmt.Errorf("no such template: %s", pageName)
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}
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return tmpl.Execute(w, data)
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}
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