120 lines
3.4 KiB
Go
120 lines
3.4 KiB
Go
package openid
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import (
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"errors"
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"io"
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"io/ioutil"
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"strings"
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"golang.org/x/net/html"
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)
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var yadisHeaders = map[string]string{
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"Accept": "application/xrds+xml"}
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func yadisDiscovery(id string, getter httpGetter) (opEndpoint string, opLocalID string, err error) {
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// Section 6.2.4 of Yadis 1.0 specifications.
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// The Yadis Protocol is initiated by the Relying Party Agent
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// with an initial HTTP request using the Yadis URL.
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// This request MUST be either a GET or a HEAD request.
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// A GET or HEAD request MAY include an HTTP Accept
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// request-header (HTTP 14.1) specifying MIME media type,
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// application/xrds+xml.
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resp, err := getter.Get(id, yadisHeaders)
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if err != nil {
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return "", "", err
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}
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defer resp.Body.Close()
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// Section 6.2.5 from Yadis 1.0 spec: Response
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contentType := resp.Header.Get("Content-Type")
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// The response MUST be one of:
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// (see 6.2.6 for precedence)
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if l := resp.Header.Get("X-XRDS-Location"); l != "" {
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// 2. HTTP response-headers that include an X-XRDS-Location
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// response-header, together with a document
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return getYadisResourceDescriptor(l, getter)
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} else if strings.Contains(contentType, "text/html") {
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// 1. An HTML document with a <head> element that includes a
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// <meta> element with http-equiv attribute, X-XRDS-Location,
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metaContent, err := findMetaXrdsLocation(resp.Body)
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if err == nil {
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return getYadisResourceDescriptor(metaContent, getter)
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}
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return "", "", err
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} else if strings.Contains(contentType, "application/xrds+xml") {
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// 4. A document of MIME media type, application/xrds+xml.
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body, err := ioutil.ReadAll(resp.Body)
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if err == nil {
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return parseXrds(body)
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}
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return "", "", err
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}
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// 3. HTTP response-headers only, which MAY include an
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// X-XRDS-Location response-header, a content-type
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// response-header specifying MIME media type,
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// application/xrds+xml, or both.
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// (this is handled by one of the 2 previous if statements)
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return "", "", errors.New("No expected header, or content type")
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}
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// Similar as above, but we expect an absolute Yadis document URL.
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func getYadisResourceDescriptor(id string, getter httpGetter) (opEndpoint string, opLocalID string, err error) {
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resp, err := getter.Get(id, yadisHeaders)
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if err != nil {
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return "", "", err
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}
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defer resp.Body.Close()
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// 4. A document of MIME media type, application/xrds+xml.
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body, err := ioutil.ReadAll(resp.Body)
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if err == nil {
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return parseXrds(body)
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}
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return "", "", err
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}
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// Search for
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// <head>
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// <meta http-equiv="X-XRDS-Location" content="....">
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func findMetaXrdsLocation(input io.Reader) (location 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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return "", tokenizer.Err()
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case html.StartTagToken, html.EndTagToken:
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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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return "", errors.New("Meta X-XRDS-Location not found")
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}
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} else if inHead && tk.Data == "meta" {
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ok := false
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content := ""
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for _, attr := range tk.Attr {
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if attr.Key == "http-equiv" &&
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strings.ToLower(attr.Val) == "x-xrds-location" {
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ok = true
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} else if attr.Key == "content" {
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content = attr.Val
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}
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}
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if ok && len(content) > 0 {
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return content, nil
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}
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}
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}
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}
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return "", errors.New("Meta X-XRDS-Location not found")
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}
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