[#887] added Spotify OAuth2 provider

tools/auth/auth.go

@@ -97,6 +97,8 @@ func NewProviderByName(name string) (Provider, error) {
 		return NewTwitterProvider(), nil
 	case NameMicrosoft:
 		return NewMicrosoftProvider(), nil
+	case NameSpotify:
+		return NewSpotifyProvider(), nil
 	default:
 		return nil, errors.New("Missing provider " + name)
 	}

tools/auth/auth_test.go

@@ -72,4 +72,13 @@ func TestNewProviderByName(t *testing.T) {
 	if _, ok := p.(*auth.Microsoft); !ok {
 		t.Error("Expected to be instance of *auth.Microsoft")
 	}
+
+	// spotify
+	p, err = auth.NewProviderByName(auth.NameSpotify)
+	if err != nil {
+		t.Errorf("Expected nil, got error %v", err)
+	}
+	if _, ok := p.(*auth.Spotify); !ok {
+		t.Error("Expected to be instance of *auth.Spotify")
+	}
 }

tools/auth/spotify.go

@@ -0,0 +1,54 @@
+package auth
+
+import (
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/spotify"
+)
+
+var _ Provider = (*Spotify)(nil)
+
+// NameSpotify is the unique name of the Spotify provider.
+const NameSpotify string = "spotify"
+
+// Spotify allows authentication via Spotify OAuth2.
+type Spotify struct {
+	*baseProvider
+}
+
+// NewSpotifyProvider creates a new Spotify provider instance with some defaults.
+func NewSpotifyProvider() *Spotify {
+	return &Spotify{&baseProvider{
+		scopes:     []string{"user-read-private", "user-read-email"},
+		authUrl:    spotify.Endpoint.AuthURL,
+		tokenUrl:   spotify.Endpoint.TokenURL,
+		userApiUrl: "https://api.spotify.com/v1/me",
+	}}
+}
+
+// FetchAuthUser returns an AuthUser instance based on the Spotify's user api.
+func (p *Spotify) FetchAuthUser(token *oauth2.Token) (*AuthUser, error) {
+	// https://developer.spotify.com/documentation/web-api/reference/#/operations/get-current-users-profile
+	rawData := struct {
+		Id     string `json:"id"`
+		Name   string `json:"display_name"`
+		Email  string `json:"email"`
+		Images []struct {
+			Url string `json:"url"`
+		} `json:"images"`
+	}{}
+
+	if err := p.FetchRawUserData(token, &rawData); err != nil {
+		return nil, err
+	}
+
+	user := &AuthUser{
+		Id:    rawData.Id,
+		Name:  rawData.Name,
+		Email: rawData.Email,
+	}
+	if len(rawData.Images) > 0 {
+		user.AvatarUrl = rawData.Images[0].Url
+	}
+
+	return user, nil
+}