add google login

- refactor resolvers
- fix signup method typos

Resolves #17

server/oauth/oauth.go

@@ -0,0 +1,45 @@
+package oauth
+
+import (
+	"github.com/yauthdev/yauth/server/constants"
+	"golang.org/x/oauth2"
+	facebookOAuth2 "golang.org/x/oauth2/facebook"
+	githubOAuth2 "golang.org/x/oauth2/github"
+	googleOAuth2 "golang.org/x/oauth2/google"
+)
+
+type OAuthProviders struct {
+	GoogleConfig   *oauth2.Config
+	GithubConfig   *oauth2.Config
+	FacebookConfig *oauth2.Config
+}
+
+var OAuthProvider OAuthProviders
+
+func init() {
+	if constants.GOOGLE_CLIENT_ID != "" && constants.GOOGLE_CLIENT_SECRET != "" {
+		OAuthProvider.GoogleConfig = &oauth2.Config{
+			ClientID:     constants.GOOGLE_CLIENT_ID,
+			ClientSecret: constants.GOOGLE_CLIENT_SECRET,
+			RedirectURL:  constants.SERVER_URL + "/callback/google",
+			Endpoint:     googleOAuth2.Endpoint,
+			Scopes:       []string{"https://www.googleapis.com/auth/userinfo.email", "https://www.googleapis.com/auth/userinfo.profile"},
+		}
+	}
+	if constants.GITHUB_CLIENT_ID != "" && constants.GITHUB_CLIENT_SECRET != "" {
+		OAuthProvider.GoogleConfig = &oauth2.Config{
+			ClientID:     constants.GITHUB_CLIENT_ID,
+			ClientSecret: constants.GITHUB_CLIENT_SECRET,
+			RedirectURL:  constants.SERVER_URL + "/callback/github",
+			Endpoint:     githubOAuth2.Endpoint,
+		}
+	}
+	if constants.FACEBOOK_CLIENT_ID != "" && constants.FACEBOOK_CLIENT_SECRET != "" {
+		OAuthProvider.GoogleConfig = &oauth2.Config{
+			ClientID:     constants.FACEBOOK_CLIENT_ID,
+			ClientSecret: constants.FACEBOOK_CLIENT_SECRET,
+			RedirectURL:  constants.SERVER_URL + "/callback/facebook/",
+			Endpoint:     facebookOAuth2.Endpoint,
+		}
+	}
+}