Authentication code is in auth now

auth/google.go

@@ -0,0 +1,102 @@
+package auth
+
+import (
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/aerogo/aero"
+	"github.com/animenotifier/arn"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+)
+
+// GoogleUser is the user data we receive from Google
+type GoogleUser struct {
+	Sub           string `json:"sub"`
+	Name          string `json:"name"`
+	GivenName     string `json:"given_name"`
+	FamilyName    string `json:"family_name"`
+	Profile       string `json:"profile"`
+	Picture       string `json:"picture"`
+	Email         string `json:"email"`
+	EmailVerified bool   `json:"email_verified"`
+	Gender        string `json:"gender"`
+}
+
+// InstallGoogleAuth enables Google login for the app.
+func InstallGoogleAuth(app *aero.Application) {
+	conf := &oauth2.Config{
+		ClientID:     apiKeys.Google.ID,
+		ClientSecret: apiKeys.Google.Secret,
+		RedirectURL:  "https://" + app.Config.Domain + "/auth/google/callback",
+		Scopes: []string{
+			"https://www.googleapis.com/auth/userinfo.email",
+		},
+		Endpoint: google.Endpoint,
+	}
+
+	// Auth
+	app.Get("/auth/google", func(ctx *aero.Context) string {
+		sessionID := ctx.Session().ID()
+		url := conf.AuthCodeURL(sessionID)
+		ctx.Redirect(url)
+		return ""
+	})
+
+	// Auth Callback
+	app.Get("/auth/google/callback", func(ctx *aero.Context) string {
+		session := ctx.Session()
+
+		if session.ID() != ctx.Query("state") {
+			return ctx.Error(http.StatusUnauthorized, "Authorization not allowed for this session", errors.New("Google login failed: Incorrect state"))
+		}
+
+		// Handle the exchange code to initiate a transport
+		token, err := conf.Exchange(oauth2.NoContext, ctx.Query("code"))
+
+		if err != nil {
+			return ctx.Error(http.StatusBadRequest, "Could not obtain OAuth token", err)
+		}
+
+		// Construct the OAuth client
+		client := conf.Client(oauth2.NoContext, token)
+
+		// Fetch user data from Google
+		resp, err := client.Get("https://www.googleapis.com/oauth2/v3/userinfo")
+
+		if err != nil {
+			return ctx.Error(http.StatusBadRequest, "Failed requesting user data from Google", err)
+		}
+
+		defer resp.Body.Close()
+		data, _ := ioutil.ReadAll(resp.Body)
+
+		// Construct a GoogleUser object
+		var googleUser GoogleUser
+		err = json.Unmarshal(data, &googleUser)
+
+		if err != nil {
+			return ctx.Error(http.StatusBadRequest, "Failed parsing user data (JSON)", err)
+		}
+
+		// Try to find an existing user by the Google user ID
+		user, getErr := arn.GetUserFromTable("GoogleToUser", googleUser.Sub)
+
+		if getErr == nil && user != nil {
+			session.Set("userId", user.ID)
+			return ctx.Redirect("/")
+		}
+
+		// Try to find an existing user by the associated e-mail address
+		user, getErr = arn.GetUserByEmail(googleUser.Email)
+
+		if getErr == nil && user != nil {
+			session.Set("userId", user.ID)
+			return ctx.Redirect("/")
+		}
+
+		return ctx.Error(http.StatusForbidden, "Account does not exist", err)
+	})
+}