forgejo-federation/vendor/github.com/yohcop/openid-go/html_discovery.go
2017-03-17 15:16:08 +01:00

77 lines
2 KiB
Go

package openid
import (
"errors"
"io"
"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" {
if attr.Val == "openid2.provider" {
provider = true
} else if attr.Val == "openid2.local_id" {
localID = true
} else if attr.Val == "openid.server" {
provider = true
}
} 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")
}