319 lines
9 KiB
Go
319 lines
9 KiB
Go
package main
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import (
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"bytes"
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"context"
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"crypto/tls"
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"crypto/x509"
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"encoding/json"
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"errors"
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"fmt"
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"net/http/httputil"
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"net/url"
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"os"
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"strings"
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"time"
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"github.com/coreos/go-oidc"
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"github.com/spf13/cobra"
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"golang.org/x/oauth2"
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)
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const exampleAppState = "I wish to wash my irish wristwatch"
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type app struct {
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clientID string
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clientSecret string
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redirectURI string
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verifier *oidc.IDTokenVerifier
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provider *oidc.Provider
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// Does the provider use "offline_access" scope to request a refresh token
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// or does it use "access_type=offline" (e.g. Google)?
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offlineAsScope bool
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ctx context.Context
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cancel context.CancelFunc
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}
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// return an HTTP client which trusts the provided root CAs.
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func httpClientForRootCAs(rootCAs string) (*http.Client, error) {
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tlsConfig := tls.Config{RootCAs: x509.NewCertPool()}
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rootCABytes, err := ioutil.ReadFile(rootCAs)
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if err != nil {
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return nil, fmt.Errorf("failed to read root-ca: %v", err)
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}
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if !tlsConfig.RootCAs.AppendCertsFromPEM(rootCABytes) {
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return nil, fmt.Errorf("no certs found in root CA file %q", rootCAs)
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}
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return &http.Client{
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Transport: &http.Transport{
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TLSClientConfig: &tlsConfig,
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Proxy: http.ProxyFromEnvironment,
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Dial: (&net.Dialer{
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Timeout: 30 * time.Second,
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KeepAlive: 30 * time.Second,
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}).Dial,
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TLSHandshakeTimeout: 10 * time.Second,
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ExpectContinueTimeout: 1 * time.Second,
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},
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}, nil
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}
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type debugTransport struct {
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t http.RoundTripper
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}
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func (d debugTransport) RoundTrip(req *http.Request) (*http.Response, error) {
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reqDump, err := httputil.DumpRequest(req, true)
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if err != nil {
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return nil, err
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}
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log.Printf("%s", reqDump)
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resp, err := d.t.RoundTrip(req)
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if err != nil {
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return nil, err
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}
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respDump, err := httputil.DumpResponse(resp, true)
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if err != nil {
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resp.Body.Close()
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return nil, err
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}
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log.Printf("%s", respDump)
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return resp, nil
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}
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func cmd() *cobra.Command {
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var (
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a app
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issuerURL string
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listen string
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tlsCert string
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tlsKey string
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rootCAs string
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debug bool
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)
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c := cobra.Command{
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Use: "example-app",
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Short: "An example OpenID Connect client",
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Long: "",
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RunE: func(cmd *cobra.Command, args []string) error {
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if len(args) != 0 {
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return errors.New("surplus arguments provided")
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}
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u, err := url.Parse(a.redirectURI)
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if err != nil {
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return fmt.Errorf("parse redirect-uri: %v", err)
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}
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listenURL, err := url.Parse(listen)
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if err != nil {
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return fmt.Errorf("parse listen address: %v", err)
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}
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a.ctx, a.cancel = context.WithCancel(context.Background())
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if rootCAs != "" {
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client, err := httpClientForRootCAs(rootCAs)
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if err != nil {
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return err
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}
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// This sets the OAuth2 client and oidc client.
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a.ctx = context.WithValue(a.ctx, oauth2.HTTPClient, client)
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}
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if debug {
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client, ok := a.ctx.Value(oauth2.HTTPClient).(*http.Client)
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if ok {
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client.Transport = debugTransport{client.Transport}
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} else {
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a.ctx = context.WithValue(a.ctx, oauth2.HTTPClient, &http.Client{
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Transport: debugTransport{http.DefaultTransport},
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})
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}
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}
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// TODO(ericchiang): Retry with backoff
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provider, err := oidc.NewProvider(a.ctx, issuerURL)
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if err != nil {
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return fmt.Errorf("Failed to query provider %q: %v", issuerURL, err)
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}
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var s struct {
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// What scopes does a provider support?
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//
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// See: https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata
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ScopesSupported []string `json:"scopes_supported"`
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}
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if err := provider.Claims(&s); err != nil {
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return fmt.Errorf("Failed to parse provider scopes_supported: %v", err)
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}
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if len(s.ScopesSupported) == 0 {
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// scopes_supported is a "RECOMMENDED" discovery claim, not a required
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// one. If missing, assume that the provider follows the spec and has
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// an "offline_access" scope.
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a.offlineAsScope = true
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} else {
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// See if scopes_supported has the "offline_access" scope.
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a.offlineAsScope = func() bool {
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for _, scope := range s.ScopesSupported {
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if scope == oidc.ScopeOfflineAccess {
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return true
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}
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}
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return false
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}()
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}
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a.provider = provider
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a.verifier = provider.Verifier(&oidc.Config{ClientID: a.clientID})
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http.HandleFunc("/", a.handleIndex)
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http.HandleFunc("/login", a.handleLogin)
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http.HandleFunc(u.Path, a.handleCallback)
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switch listenURL.Scheme {
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case "http":
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log.Printf("listening on %s", listen)
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return http.ListenAndServe(listenURL.Host, nil)
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case "https":
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log.Printf("listening on %s", listen)
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return http.ListenAndServeTLS(listenURL.Host, tlsCert, tlsKey, nil)
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default:
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return fmt.Errorf("listen address %q is not using http or https", listen)
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}
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},
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}
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c.Flags().StringVar(&a.clientID, "client-id", "example-app", "OAuth2 client ID of this application.")
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c.Flags().StringVar(&a.clientSecret, "client-secret", "ZXhhbXBsZS1hcHAtc2VjcmV0", "OAuth2 client secret of this application.")
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c.Flags().StringVar(&a.redirectURI, "redirect-uri", "http://127.0.0.1:5555/callback", "Callback URL for OAuth2 responses.")
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c.Flags().StringVar(&issuerURL, "issuer", "http://127.0.0.1:5556/dex", "URL of the OpenID Connect issuer.")
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c.Flags().StringVar(&listen, "listen", "http://127.0.0.1:5555", "HTTP(S) address to listen at.")
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c.Flags().StringVar(&tlsCert, "tls-cert", "", "X509 cert file to present when serving HTTPS.")
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c.Flags().StringVar(&tlsKey, "tls-key", "", "Private key for the HTTPS cert.")
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c.Flags().StringVar(&rootCAs, "issuer-root-ca", "", "Root certificate authorities for the issuer. Defaults to host certs.")
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c.Flags().BoolVar(&debug, "debug", false, "Print all request and responses from the OpenID Connect issuer.")
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return &c
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}
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func main() {
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if err := cmd().Execute(); err != nil {
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fmt.Fprintf(os.Stderr, "error: %v\n", err)
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os.Exit(2)
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}
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}
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func (a *app) handleIndex(w http.ResponseWriter, r *http.Request) {
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renderIndex(w)
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}
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func (a *app) oauth2Config(scopes []string) *oauth2.Config {
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return &oauth2.Config{
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ClientID: a.clientID,
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ClientSecret: a.clientSecret,
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Endpoint: a.provider.Endpoint(),
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Scopes: scopes,
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RedirectURL: a.redirectURI,
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}
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}
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func (a *app) handleLogin(w http.ResponseWriter, r *http.Request) {
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var scopes []string
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if extraScopes := r.FormValue("extra_scopes"); extraScopes != "" {
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scopes = strings.Split(extraScopes, " ")
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}
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var clients []string
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if crossClients := r.FormValue("cross_client"); crossClients != "" {
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clients = strings.Split(crossClients, " ")
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}
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for _, client := range clients {
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scopes = append(scopes, "audience:server:client_id:"+client)
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}
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authCodeURL := ""
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scopes = append(scopes, "openid", "profile", "email")
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if r.FormValue("offline_access") != "yes" {
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authCodeURL = a.oauth2Config(scopes).AuthCodeURL(exampleAppState)
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} else if a.offlineAsScope {
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scopes = append(scopes, "offline_access")
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authCodeURL = a.oauth2Config(scopes).AuthCodeURL(exampleAppState)
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} else {
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authCodeURL = a.oauth2Config(scopes).AuthCodeURL(exampleAppState, oauth2.AccessTypeOffline)
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}
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http.Redirect(w, r, authCodeURL, http.StatusSeeOther)
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}
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func (a *app) handleCallback(w http.ResponseWriter, r *http.Request) {
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var (
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err error
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token *oauth2.Token
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)
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oauth2Config := a.oauth2Config(nil)
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switch r.Method {
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case "GET":
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// Authorization redirect callback from OAuth2 auth flow.
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if errMsg := r.FormValue("error"); errMsg != "" {
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http.Error(w, errMsg+": "+r.FormValue("error_description"), http.StatusBadRequest)
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return
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}
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code := r.FormValue("code")
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if code == "" {
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http.Error(w, fmt.Sprintf("no code in request: %q", r.Form), http.StatusBadRequest)
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return
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}
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if state := r.FormValue("state"); state != exampleAppState {
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http.Error(w, fmt.Sprintf("expected state %q got %q", exampleAppState, state), http.StatusBadRequest)
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return
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}
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token, err = oauth2Config.Exchange(a.ctx, code)
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case "POST":
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// Form request from frontend to refresh a token.
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refresh := r.FormValue("refresh_token")
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if refresh == "" {
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http.Error(w, fmt.Sprintf("no refresh_token in request: %q", r.Form), http.StatusBadRequest)
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return
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}
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t := &oauth2.Token{
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RefreshToken: refresh,
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Expiry: time.Now().Add(-time.Hour),
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}
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token, err = oauth2Config.TokenSource(r.Context(), t).Token()
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default:
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http.Error(w, fmt.Sprintf("method not implemented: %s", r.Method), http.StatusBadRequest)
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return
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}
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if err != nil {
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http.Error(w, fmt.Sprintf("failed to get token: %v", err), http.StatusInternalServerError)
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return
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}
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rawIDToken, ok := token.Extra("id_token").(string)
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if !ok {
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http.Error(w, "no id_token in token response", http.StatusInternalServerError)
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return
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}
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idToken, err := a.verifier.Verify(r.Context(), rawIDToken)
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if err != nil {
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http.Error(w, fmt.Sprintf("Failed to verify ID token: %v", err), http.StatusInternalServerError)
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return
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}
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var claims json.RawMessage
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idToken.Claims(&claims)
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buff := new(bytes.Buffer)
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json.Indent(buff, []byte(claims), "", " ")
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renderToken(w, a.redirectURI, rawIDToken, token.RefreshToken, buff.Bytes())
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}
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