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// Package oidc implements logging in through OpenID Connect providers.
package oidc
import (
"errors"
"fmt"
"net/http"
"os"
"github.com/ericchiang/oidc"
"golang.org/x/net/context"
"golang.org/x/oauth2"
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)
// Config holds configuration options for OpenID Connect logins.
type Config struct {
Issuer string `yaml:"issuer"`
ClientID string `yaml:"clientID"`
ClientSecret string `yaml:"clientSecret"`
RedirectURI string `yaml:"redirectURI"`
Scopes []string `yaml:"scopes"` // defaults to "profile" and "email"
}
// Open returns a connector which can be used to login users through an upstream
// OpenID Connect provider.
func (c *Config) Open() (conn connector.Connector, err error) {
ctx, cancel := context.WithCancel(context.Background())
provider, err := oidc.NewProvider(ctx, c.Issuer)
if err != nil {
cancel()
return nil, fmt.Errorf("failed to get provider: %v", err)
}
scopes := []string{oidc.ScopeOpenID}
if len(c.Scopes) > 0 {
scopes = append(scopes, c.Scopes...)
} else {
scopes = append(scopes, "profile", "email")
}
clientID := os.ExpandEnv(c.ClientID)
return &oidcConnector{
redirectURI: c.RedirectURI,
oauth2Config: &oauth2.Config{
ClientID: clientID,
ClientSecret: os.ExpandEnv(c.ClientSecret),
Endpoint: provider.Endpoint(),
Scopes: scopes,
RedirectURL: c.RedirectURI,
},
verifier: provider.NewVerifier(ctx,
oidc.VerifyExpiry(),
oidc.VerifyAudience(clientID),
),
}, nil
}
var (
_ connector.CallbackConnector = (*oidcConnector)(nil)
)
type oidcConnector struct {
redirectURI string
oauth2Config *oauth2.Config
verifier *oidc.IDTokenVerifier
ctx context.Context
cancel context.CancelFunc
}
func (c *oidcConnector) Close() error {
c.cancel()
return nil
}
func (c *oidcConnector) LoginURL(callbackURL, state string) (string, error) {
if c.redirectURI != callbackURL {
return "", fmt.Errorf("expected callback URL did not match the URL in the config")
}
return c.oauth2Config.AuthCodeURL(state), nil
}
type oauth2Error struct {
error string
errorDescription string
}
func (e *oauth2Error) Error() string {
if e.errorDescription == "" {
return e.error
}
return e.error + ": " + e.errorDescription
}
func (c *oidcConnector) HandleCallback(r *http.Request) (identity connector.Identity, state string, err error) {
q := r.URL.Query()
if errType := q.Get("error"); errType != "" {
return identity, "", &oauth2Error{errType, q.Get("error_description")}
}
token, err := c.oauth2Config.Exchange(c.ctx, q.Get("code"))
if err != nil {
return identity, "", fmt.Errorf("oidc: failed to get token: %v", err)
}
rawIDToken, ok := token.Extra("id_token").(string)
if !ok {
return identity, "", errors.New("oidc: no id_token in token response")
}
idToken, err := c.verifier.Verify(rawIDToken)
if err != nil {
return identity, "", fmt.Errorf("oidc: failed to verify ID Token: %v", err)
}
var claims struct {
Username string `json:"name"`
Email string `json:"email"`
EmailVerified bool `json:"email_verified"`
}
if err := idToken.Claims(&claims); err != nil {
return identity, "", fmt.Errorf("oidc: failed to decode claims: %v", err)
}
identity = connector.Identity{
UserID: idToken.Subject,
Username: claims.Username,
Email: claims.Email,
EmailVerified: claims.EmailVerified,
}
return identity, q.Get("state"), nil
}