[#3323] added Patreon OAuth2 provider

Co-authored-by: GHOST <ghostdevbusiness@gmail.com>

tools/auth/patreon.go

@@ -0,0 +1,78 @@
+package auth
+
+import (
+	"context"
+	"encoding/json"
+
+	"golang.org/x/oauth2"
+)
+
+var _ Provider = (*Patreon)(nil)
+
+// NamePatreon is the unique name of the Patreon provider.
+const NamePatreon string = "patreon"
+
+// Patreon allows authentication via Patreon OAuth2.
+type Patreon struct {
+	*baseProvider
+}
+
+// NewPatreonProvider creates new Patreon provider instance with some defaults.
+func NewPatreonProvider() *Patreon {
+	return &Patreon{&baseProvider{
+		ctx:        context.Background(),
+		scopes:     []string{"identity", "identity[email]"},
+		authUrl:    "https://www.patreon.com/oauth2/authorize",
+		tokenUrl:   "https://www.patreon.com/api/oauth2/token",
+		userApiUrl: "https://www.patreon.com/api/oauth2/v2/identity?fields%5Buser%5D=full_name,email,vanity,image_url,is_email_verified",
+	}}
+}
+
+// FetchAuthUser returns an AuthUser instance based on the Patreons's identity api.
+//
+// API reference:
+// https://docs.patreon.com/#get-api-oauth2-v2-identity
+// https://docs.patreon.com/#user-v2
+func (p *Patreon) FetchAuthUser(token *oauth2.Token) (*AuthUser, error) {
+	data, err := p.FetchRawUserData(token)
+	if err != nil {
+		return nil, err
+	}
+
+	rawUser := map[string]any{}
+	if err := json.Unmarshal(data, &rawUser); err != nil {
+		return nil, err
+	}
+
+	extracted := struct {
+		Data struct {
+			Id         string `json:"id"`
+			Attributes struct {
+				Email           string `json:"email"`
+				Name            string `json:"full_name"`
+				Username        string `json:"vanity"`
+				AvatarUrl       string `json:"image_url"`
+				IsEmailVerified bool   `json:"is_email_verified"`
+			} `json:"attributes"`
+		} `json:"data"`
+	}{}
+	if err := json.Unmarshal(data, &extracted); err != nil {
+		return nil, err
+	}
+
+	user := &AuthUser{
+		Id:           extracted.Data.Id,
+		Username:     extracted.Data.Attributes.Username,
+		Name:         extracted.Data.Attributes.Name,
+		AvatarUrl:    extracted.Data.Attributes.AvatarUrl,
+		RawUser:      rawUser,
+		AccessToken:  token.AccessToken,
+		RefreshToken: token.RefreshToken,
+	}
+
+	if extracted.Data.Attributes.IsEmailVerified {
+		user.Email = extracted.Data.Attributes.Email
+	}
+
+	return user, nil
+}