Add Gitea connector (#1715)

* Add Gitea connector

* Add details to readme

* resolve lint issue

connector/gitea/gitea_test.go

@@ -0,0 +1,72 @@
+package gitea
+
+import (
+	"crypto/tls"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"reflect"
+	"testing"
+
+	"github.com/dexidp/dex/connector"
+)
+
+// tests that the email is used as their username when they have no username set
+func TestUsernameIncludedInFederatedIdentity(t *testing.T) {
+	s := newTestServer(map[string]interface{}{
+		"/api/v1/user": giteaUser{Email: "some@email.com", ID: 12345678},
+		"/login/oauth/access_token": map[string]interface{}{
+			"access_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9",
+			"expires_in":   "30",
+		},
+	})
+	defer s.Close()
+
+	hostURL, err := url.Parse(s.URL)
+	expectNil(t, err)
+
+	req, err := http.NewRequest("GET", hostURL.String(), nil)
+	expectNil(t, err)
+
+	c := giteaConnector{baseURL: s.URL, httpClient: newClient()}
+	identity, err := c.HandleCallback(connector.Scopes{}, req)
+
+	expectNil(t, err)
+	expectEquals(t, identity.Username, "some@email.com")
+	expectEquals(t, identity.UserID, "12345678")
+
+	c = giteaConnector{baseURL: s.URL, httpClient: newClient()}
+	identity, err = c.HandleCallback(connector.Scopes{}, req)
+
+	expectNil(t, err)
+	expectEquals(t, identity.Username, "some@email.com")
+	expectEquals(t, identity.UserID, "12345678")
+}
+
+func newTestServer(responses map[string]interface{}) *httptest.Server {
+	return httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		response := responses[r.RequestURI]
+		w.Header().Add("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(response)
+	}))
+}
+
+func newClient() *http.Client {
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+	return &http.Client{Transport: tr}
+}
+
+func expectNil(t *testing.T, a interface{}) {
+	if a != nil {
+		t.Errorf("Expected %+v to equal nil", a)
+	}
+}
+
+func expectEquals(t *testing.T, a interface{}, b interface{}) {
+	if !reflect.DeepEqual(a, b) {
+		t.Errorf("Expected %+v to equal %+v", a, b)
+	}
+}