escape.go

package rest

import (
	"fmt"
	"net/http"
	"strings"
	"unicode"
)

func RuneIsAscii(c rune) bool {
	return c < unicode.MaxASCII
}

func FileNameIsAscii(filename string) bool {
	for _, c := range filename {
		if !RuneIsAscii(c) {
			return false
		}
	}
	return true
}

func RuneNeedEscape(c rune) bool {
	if !RuneIsAscii(c) {
		return false
	}
	if uint(c) < 0x20 {
		return true
	}
	return c == ';' || c == '\n' || c == '"' || c == '\\'
}

func RuneEscape(c rune) rune {
	if RuneNeedEscape(c) {
		return '_'
	} else {
		return c
	}
}

func FileNameEscape(filename string) string {
	return strings.Map(RuneEscape, filename)
}

func ContentDispositionAttachment(header http.Header, filename string) {
	filename = FileNameEscape(filename)

	var value string
	if FileNameIsAscii(filename) {
		value = `attachment; filename=%s`
	} else {
		value = `attachment; filename*=UTF-8''%s`
	}
	header.Set("Content-Disposition", fmt.Sprintf(value, filename))
}