package http import ( "bytes" "embed" "fmt" "html/template" "io/fs" "net/http" "path/filepath" "strings" "time" "github.com/mediocregopher/blog.mediocregopher.com/srv/http/apiutil" ) //go:embed tpl var tplFS embed.FS func mustReadTplFile(fileName string) string { path := filepath.Join("tpl", fileName) b, err := fs.ReadFile(tplFS, path) if err != nil { panic(fmt.Errorf("reading file %q from tplFS: %w", path, err)) } return string(b) } func (a *api) parseTpl(tplBody string) (*template.Template, error) { blogURL := func(path string) string { // filepath.Join strips trailing slash, but we want to keep it trailingSlash := strings.HasSuffix(path, "/") path = filepath.Join("/", a.params.PathPrefix, path) if trailingSlash && path != "/" { path += "/" } return path } tpl := template.New("root") tpl = tpl.Funcs(template.FuncMap{ "BlogURL": blogURL, "StaticURL": func(path string) string { path = filepath.Join("static", path) return blogURL(path) }, "AssetURL": func(id string) string { path := filepath.Join("assets", id) return blogURL(path) }, "PostURL": func(id string) string { path := filepath.Join("posts", id) return blogURL(path) }, "DateTimeFormat": func(t time.Time) string { return t.Format("2006-01-02") }, }) tpl = template.Must(tpl.New("image.html").Parse(mustReadTplFile("image.html"))) tpl = tpl.Funcs(template.FuncMap{ "Image": func(id string) (template.HTML, error) { tplPayload := struct { ID string Resizable bool }{ ID: id, Resizable: isImgResizable(id), } buf := new(bytes.Buffer) if err := tpl.ExecuteTemplate(buf, "image.html", tplPayload); err != nil { return "", err } return template.HTML(buf.Bytes()), nil }, }) var err error if tpl, err = tpl.New("").Parse(tplBody); err != nil { return nil, err } return tpl, nil } func (a *api) mustParseTpl(name string) *template.Template { return template.Must(a.parseTpl(mustReadTplFile(name))) } func (a *api) mustParseBasedTpl(name string) *template.Template { tpl := a.mustParseTpl(name) tpl = template.Must(tpl.New("base.html").Parse(mustReadTplFile("base.html"))) return tpl } type tplData struct { Payload interface{} CSRFToken string } func (t tplData) CSRFFormInput() template.HTML { return template.HTML(fmt.Sprintf( ``, csrfTokenFormName, t.CSRFToken, )) } // executeTemplate expects to be the final action in an http.Handler func executeTemplate( rw http.ResponseWriter, r *http.Request, tpl *template.Template, payload interface{}, ) { csrfToken, _ := apiutil.GetCookie(r, csrfTokenCookieName, "") tplData := tplData{ Payload: payload, CSRFToken: csrfToken, } if err := tpl.Execute(rw, tplData); err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("rendering template: %w", err), ) return } } func (a *api) executeRedirectTpl( rw http.ResponseWriter, r *http.Request, path string, ) { executeTemplate(rw, r, a.redirectTpl, struct { Path string }{ Path: path, }) } func (a *api) renderDumbTplHandler(tplName string) http.Handler { tpl := a.mustParseBasedTpl(tplName) return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { if err := tpl.Execute(rw, nil); err != nil { apiutil.InternalServerError( rw, r, fmt.Errorf("rendering %q: %w", tplName, err), ) return } }) }