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package openid
import (
"errors"
"io"
"strings"
"golang.org/x/net/html"
)
func htmlDiscovery(id string, getter httpGetter) (opEndpoint, opLocalID, claimedID string, err error) {
resp, err := getter.Get(id, nil)
if err != nil {
return "", "", "", err
}
opEndpoint, opLocalID, err = findProviderFromHeadLink(resp.Body)
return opEndpoint, opLocalID, resp.Request.URL.String(), err
}
func findProviderFromHeadLink(input io.Reader) (opEndpoint, opLocalID string, err error) {
tokenizer := html.NewTokenizer(input)
inHead := false
for {
tt := tokenizer.Next()
switch tt {
case html.ErrorToken:
// Even if the document is malformed after we found a
// valid <link> tag, ignore and let's be happy with our
// openid2.provider and potentially openid2.local_id as well.
if len(opEndpoint) > 0 {
return
}
return "", "", tokenizer.Err()
case html.StartTagToken, html.EndTagToken, html.SelfClosingTagToken:
tk := tokenizer.Token()
if tk.Data == "head" {
if tt == html.StartTagToken {
inHead = true
} else {
if len(opEndpoint) > 0 {
return
}
return "", "", errors.New(
"LINK with rel=openid2.provider not found")
}
} else if inHead && tk.Data == "link" {
provider := false
localID := false
href := ""
for _, attr := range tk.Attr {
if attr.Key == "rel" {
// There could be multiple values in the rel= attribute,
// space-separated (it seems to be for OpenID1 vs 2.)
// See example in Appendix A.4. HTML Identifier Markup.
vals := strings.Split(attr.Val, " ")
for _, val := range vals {
if val == "openid2.provider" {
provider = true
break
} else if val == "openid2.local_id" {
localID = true
break
}
}
} else if attr.Key == "href" {
href = attr.Val
}
}
if provider && !localID && len(href) > 0 {
opEndpoint = href
} else if !provider && localID && len(href) > 0 {
opLocalID = href
}
}
}
}
// At this point we should probably have returned either from
// a closing </head> or a tokenizer error (no </head> found).
// But just in case.
if len(opEndpoint) > 0 {
return
}
return "", "", errors.New("LINK rel=openid2.provider not found")
}
|
