78 lines
2.0 KiB
Go
78 lines
2.0 KiB
Go
package openid
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import (
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"errors"
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"io"
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"golang.org/x/net/html"
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)
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func htmlDiscovery(id string, getter httpGetter) (opEndpoint, opLocalID, claimedID string, err error) {
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resp, err := getter.Get(id, nil)
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if err != nil {
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return "", "", "", err
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}
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opEndpoint, opLocalID, err = findProviderFromHeadLink(resp.Body)
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return opEndpoint, opLocalID, resp.Request.URL.String(), err
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}
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func findProviderFromHeadLink(input io.Reader) (opEndpoint, opLocalID string, err error) {
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tokenizer := html.NewTokenizer(input)
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inHead := false
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for {
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tt := tokenizer.Next()
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switch tt {
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case html.ErrorToken:
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// Even if the document is malformed after we found a
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// valid <link> tag, ignore and let's be happy with our
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// openid2.provider and potentially openid2.local_id as well.
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if len(opEndpoint) > 0 {
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return
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}
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return "", "", tokenizer.Err()
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case html.StartTagToken, html.EndTagToken, html.SelfClosingTagToken:
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tk := tokenizer.Token()
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if tk.Data == "head" {
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if tt == html.StartTagToken {
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inHead = true
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} else {
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if len(opEndpoint) > 0 {
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return
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}
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return "", "", errors.New(
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"LINK with rel=openid2.provider not found")
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}
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} else if inHead && tk.Data == "link" {
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provider := false
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localID := false
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href := ""
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for _, attr := range tk.Attr {
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if attr.Key == "rel" {
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if attr.Val == "openid2.provider" {
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provider = true
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} else if attr.Val == "openid2.local_id" {
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localID = true
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} else if attr.Val == "openid.server" {
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provider = true
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}
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} else if attr.Key == "href" {
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href = attr.Val
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}
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}
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if provider && !localID && len(href) > 0 {
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opEndpoint = href
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} else if !provider && localID && len(href) > 0 {
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opLocalID = href
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}
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}
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}
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}
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// At this point we should probably have returned either from
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// a closing </head> or a tokenizer error (no </head> found).
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// But just in case.
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if len(opEndpoint) > 0 {
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return
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}
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return "", "", errors.New("LINK rel=openid2.provider not found")
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}
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