Populate a user's OAuthGroups using Microsoft Graph memberOf endpoint

internal/providers/microsoft.go

@@ -2,10 +2,12 @@ package providers
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
 	"strings"
 	"tinyauth/internal/constants"
+
 	"github.com/rs/zerolog/log"
 )
 
@@ -14,11 +16,23 @@ type MicrosoftUserInfoResponse struct {
 	Mail              string `json:"mail"`
 	UserPrincipalName string `json:"userPrincipalName"`
 	DisplayName       string `json:"displayName"`
+	ID                string `json:"ID"`
+}
+
+// Response for the Microsoft Graph memberOf endpoint
+type MicrosoftUserGroupsResponse struct {
+	Value []MicrosoftGroup `json:"value"`
+}
+
+// Individual group object
+type MicrosoftGroup struct {
+	ID          string `json:"id"`
+	DisplayName string `json:"displayName"`
 }
 
 // The scopes required for the Microsoft provider
 func MicrosoftScopes() []string {
-	return []string{"openid", "profile", "email", "User.Read"}
+	return []string{"openid", "profile", "email", "User.Read", "GroupMember.Read.All"}
 }
 
 func GetMicrosoftUser(client *http.Client, userURL ...string) (constants.Claims, error) {
@@ -52,6 +66,33 @@ func GetMicrosoftUser(client *http.Client, userURL ...string) (constants.Claims,
 		return user, err
 	}
 
+	log.Debug().Msg("Attempt to parse user groups from microsoft")
+
+	memberOfURL := fmt.Sprintf("https://graph.microsoft.com/v1.0/users/%s/memberOf", userInfo.ID)
+	groupRes, err := client.Get(memberOfURL)
+	if err != nil {
+		return user, err
+	}
+	defer groupRes.Body.Close()
+
+	log.Debug().Msg("Got group response from microsoft")
+
+	groupBody, err := io.ReadAll(groupRes.Body)
+	if err != nil {
+		return user, err
+	}
+
+	var groupResponse MicrosoftUserGroupsResponse
+	if err := json.Unmarshal(groupBody, &groupResponse); err != nil {
+		return user, err
+	}
+
+	// Collect group names
+	groupNames := []any{}
+	for _, g := range groupResponse.Value {
+		groupNames = append(groupNames, g.DisplayName)
+	}
+
 	log.Debug().Msg("Parsed user from microsoft")
 
 	// Prefer mail, fallback to UserPrincipalName
@@ -62,6 +103,7 @@ func GetMicrosoftUser(client *http.Client, userURL ...string) (constants.Claims,
 	user.PreferredUsername = strings.Split(email, "@")[0]
 	user.Name = userInfo.DisplayName
 	user.Email = email
+	user.Groups = groupNames
 
 	return user, nil
 }