support for custom github endpoints (#115)

* support for custom github endpoints

* implementing requested changes

* refactor 'GitHubEndpointURL' to 'EndpointURL'

config/example.yaml

@@ -13,6 +13,7 @@ Google:  # only relevant when using the oauth authbackend
 GitHub:  # only relevant when using the oauth authbackend
   ClientID: replace me
   ClientSecret: replace me
+  EndpointURL: # (OPTIONAL) URL for custom endpoint (currently only for github); e.g. 'https://github.mydomain.com'
 Microsoft:  # only relevant when using the oauth authbackend
   ClientID: replace me
   ClientSecret: 'replace me'

internal/handlers/auth.go

@@ -25,7 +25,7 @@ func (h *Handler) initOAuth() {
 	}
 	github := util.GetConfig().GitHub
 	if github.Enabled() {
-		auth.WithAdapterWrapper(auth.NewGithubAdapter(github.ClientID, github.ClientSecret), h.engine.Group("/api/v1/auth/github"))
+		auth.WithAdapterWrapper(auth.NewGithubAdapter(github.ClientID, github.ClientSecret, github.EndpointURL), h.engine.Group("/api/v1/auth/github"))
 		h.providers = append(h.providers, "github")
 	}
 	microsoft := util.GetConfig().Microsoft

internal/handlers/auth/github.go

@@ -18,7 +18,11 @@ type githubAdapter struct {
 }
 
 // NewGithubAdapter creates an oAuth adapter out of the credentials and the baseURL
-func NewGithubAdapter(clientID, clientSecret string) Adapter {
+func NewGithubAdapter(clientID, clientSecret, endpointURL string) Adapter {
+	if endpointURL != "" {
+		github.Endpoint.AuthURL = endpointURL + "/login/oauth/authorize"
+		github.Endpoint.TokenURL = endpointURL + "/login/oauth/access_token"
+	}
 	return &githubAdapter{&oauth2.Config{
 		ClientID:     clientID,
 		ClientSecret: clientSecret,
@@ -40,7 +44,12 @@ func (a *githubAdapter) GetUserData(state, code string) (*user, error) {
 	if err != nil {
 		return nil, errors.Wrap(err, "could not exchange code")
 	}
-	oAuthUserInfoReq, err := a.config.Client(context.Background(), oAuthToken).Get("https://api.github.com/user")
+
+	gitHubUserURL := "https://api.github.com/user"
+	if util.GetConfig().GitHub.EndpointURL != "" {
+		gitHubUserURL = util.GetConfig().GitHub.EndpointURL + "/api/v3/user"
+	}
+	oAuthUserInfoReq, err := a.config.Client(context.Background(), oAuthToken).Get(gitHubUserURL)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get user data")
 	}

internal/util/config.go

@@ -43,6 +43,7 @@ type redisConf struct {
 type oAuthConf struct {
 	ClientID     string `yaml:"ClientID" env:"CLIENT_ID"`
 	ClientSecret string `yaml:"ClientSecret" env:"CLIENT_SECRET"`
+	EndpointURL  string `yaml:"EndPointURL" env:"ENDPOINT_URL"` // optional for only GitHub
 }
 
 type proxyAuthConf struct {