distribution/docs/client/auth/authchallenge.go
Derek McGowan 5a3a9c6a77 Separate version and challenge parsing from ping
Replace ping logic with individual functions to extract API version and authorization challenges. The response from a ping operation can be passed into these function. If an error occurs in parsing, the version or challenge will not be used. Sending the ping request is the responsibility of the caller.
APIVersion has been converted from a string to a structure type. A parse function was added to convert from string to the structure type.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
2015-07-01 15:00:25 -07:00

166 lines
3.7 KiB
Go

package auth
import (
"net/http"
"strings"
)
// Challenge carries information from a WWW-Authenticate response header.
// See RFC 2617.
type Challenge struct {
// Scheme is the auth-scheme according to RFC 2617
Scheme string
// Parameters are the auth-params according to RFC 2617
Parameters map[string]string
}
// Octet types from RFC 2616.
type octetType byte
var octetTypes [256]octetType
const (
isToken octetType = 1 << iota
isSpace
)
func init() {
// OCTET = <any 8-bit sequence of data>
// CHAR = <any US-ASCII character (octets 0 - 127)>
// CTL = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
// CR = <US-ASCII CR, carriage return (13)>
// LF = <US-ASCII LF, linefeed (10)>
// SP = <US-ASCII SP, space (32)>
// HT = <US-ASCII HT, horizontal-tab (9)>
// <"> = <US-ASCII double-quote mark (34)>
// CRLF = CR LF
// LWS = [CRLF] 1*( SP | HT )
// TEXT = <any OCTET except CTLs, but including LWS>
// separators = "(" | ")" | "<" | ">" | "@" | "," | ";" | ":" | "\" | <">
// | "/" | "[" | "]" | "?" | "=" | "{" | "}" | SP | HT
// token = 1*<any CHAR except CTLs or separators>
// qdtext = <any TEXT except <">>
for c := 0; c < 256; c++ {
var t octetType
isCtl := c <= 31 || c == 127
isChar := 0 <= c && c <= 127
isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0
if strings.IndexRune(" \t\r\n", rune(c)) >= 0 {
t |= isSpace
}
if isChar && !isCtl && !isSeparator {
t |= isToken
}
octetTypes[c] = t
}
}
// ResponseChallenges returns a list of authorization challenges
// for the given http Response. Challenges are only checked if
// the response status code was a 401.
func ResponseChallenges(resp *http.Response) []Challenge {
if resp.StatusCode == http.StatusUnauthorized {
// Parse the WWW-Authenticate Header and store the challenges
// on this endpoint object.
return parseAuthHeader(resp.Header)
}
return nil
}
func parseAuthHeader(header http.Header) []Challenge {
challenges := []Challenge{}
for _, h := range header[http.CanonicalHeaderKey("WWW-Authenticate")] {
v, p := parseValueAndParams(h)
if v != "" {
challenges = append(challenges, Challenge{Scheme: v, Parameters: p})
}
}
return challenges
}
func parseValueAndParams(header string) (value string, params map[string]string) {
params = make(map[string]string)
value, s := expectToken(header)
if value == "" {
return
}
value = strings.ToLower(value)
s = "," + skipSpace(s)
for strings.HasPrefix(s, ",") {
var pkey string
pkey, s = expectToken(skipSpace(s[1:]))
if pkey == "" {
return
}
if !strings.HasPrefix(s, "=") {
return
}
var pvalue string
pvalue, s = expectTokenOrQuoted(s[1:])
if pvalue == "" {
return
}
pkey = strings.ToLower(pkey)
params[pkey] = pvalue
s = skipSpace(s)
}
return
}
func skipSpace(s string) (rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isSpace == 0 {
break
}
}
return s[i:]
}
func expectToken(s string) (token, rest string) {
i := 0
for ; i < len(s); i++ {
if octetTypes[s[i]]&isToken == 0 {
break
}
}
return s[:i], s[i:]
}
func expectTokenOrQuoted(s string) (value string, rest string) {
if !strings.HasPrefix(s, "\"") {
return expectToken(s)
}
s = s[1:]
for i := 0; i < len(s); i++ {
switch s[i] {
case '"':
return s[:i], s[i+1:]
case '\\':
p := make([]byte, len(s)-1)
j := copy(p, s[:i])
escape := true
for i = i + 1; i < len(s); i++ {
b := s[i]
switch {
case escape:
escape = false
p[j] = b
j++
case b == '\\':
escape = true
case b == '"':
return string(p[:j]), s[i+1:]
default:
p[j] = b
j++
}
}
return "", ""
}
}
return "", ""
}