escape.go

package aws

import (
	"http"
	"sort"
)

// (2011-06-21) - The standard go http.Values.Escape
// works properly for SQS  and S3, but it should be
// noted that at least SDB requiers more to be escaped
// than is officially standard.
//
// Sorted Escape also sorts the keys before joining them (needed
// for canonicalization).
func SortedEscape(v http.Values) (out string) {
	keys := []string{}
	for k, _ := range v {
		keys = append(keys, k)
	}
	sort.SortStrings(keys)
	for k := range keys {
		if k > 0 {
			out += "&"
		}
		// out += http.URLEscape(keys[k]) + "=" + http.URLEscape(v.Get(keys[k]))
		out += escape(keys[k]) + "=" + escape(v.Get(keys[k]))
	}
	return
}

func escapeTest(b byte) (out bool) {
	switch b {
	case 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
		'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
		'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
		'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
		'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '.', '_':
		out = false
	default:
		out = true
	}
	return
}

func escape(in string) (out string) {
	return _escape(in, escapeTest, _percentUpper)
}

// Copied from urltools to avoid the need to import it

// Escape the string as follows: if etf(b) returns true, use the value generated
// by ef(b), else use b.
func _escape(in string, etf func(byte) bool, ef func(byte) string) (out string) {
	for i := range in {
		if etf(in[i]) {
			out += ef(in[i])
		} else {
			out += string(in[i])
		}
	}
	return
}

// Returns the hex encoded (upper-case) value of byte.
func _hexEncodeUpper(b byte) (out string) {
	hb := []byte{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}
	out = string([]byte{hb[(b&0xf0)>>4], hb[(b & 0x0f)]})
	return
}

// Returns the hex encoded (upper-case) value of byte with a % prepended.
func _percentUpper(b byte) (out string) {
	return "%" + _hexEncodeUpper(b)
}