feat: Add OIDC compliant 'picture' attribute mapping

src/main/java/org/keycloak/social/discord/DiscordIdentityProvider.java

@@ -18,6 +18,7 @@
 package org.keycloak.social.discord;
 
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import jakarta.ws.rs.core.Response;
 import org.jboss.logging.Logger;
 import org.keycloak.broker.oidc.AbstractOAuth2IdentityProvider;
@@ -32,6 +33,7 @@ import org.keycloak.services.ErrorPageException;
 import org.keycloak.services.messages.Messages;
 
 import java.util.Set;
+import java.util.regex.Pattern;
 
 /**
  * @author <a href="mailto:wadahiro@gmail.com">Hiroyuki Wada</a>
@@ -45,9 +47,13 @@ public class DiscordIdentityProvider extends AbstractOAuth2IdentityProvider<Disc
     public static final String TOKEN_URL = "https://discord.com/api/oauth2/token";
     public static final String PROFILE_URL = "https://discord.com/api/users/@me";
     public static final String GROUP_URL = "https://discord.com/api/users/@me/guilds";
+    public static final String USER_PICTURE_URL = "https://cdn.discordapp.com/avatars/%s/%s.%s";
     public static final String DEFAULT_SCOPE = "identify email";
     public static final String GUILDS_SCOPE = "guilds";
 
+    private static final Pattern AVATAR_HASH_PATTERN = Pattern.compile("^(a_)?[0-9a-f]{32}$");
+    private static final Pattern DISCORD_ID_PATTERN = Pattern.compile("^\\d+$");
+
     public DiscordIdentityProvider(KeycloakSession session, DiscordIdentityProviderConfig config) {
         super(session, config);
         config.setAuthorizationUrl(AUTH_URL);
@@ -78,6 +84,8 @@ public class DiscordIdentityProvider extends AbstractOAuth2IdentityProvider<Disc
 
         user.setUsername(username);
         user.setEmail(getJsonProperty(profile, "email"));
+
+        setUserPicture(user, profile);
         user.setIdp(this);
 
         AbstractJsonUserAttributeMapper.storeUserProfileForMapper(user, profile, getConfig().getAlias());
@@ -85,6 +93,34 @@ public class DiscordIdentityProvider extends AbstractOAuth2IdentityProvider<Disc
         return user;
     }
 
+    /**
+     * Constructs the OIDC 'picture' URL based on the Discord avatar hash and sets it
+     * in the user context to ensure OIDC compliance.
+     * <p>Discord returns an avatar hash (or null), but OIDC expects a direct URL
+     * to the image in the 'picture' claim.</p>
+     * @param user The context where the 'picture' attribute will be set
+     * @param profile The raw Discord user profile JSON containing the 'avatar' hash
+     */
+    private void setUserPicture(BrokeredIdentityContext user, JsonNode profile) {
+        if (user.getId() == null || !DISCORD_ID_PATTERN.matcher(user.getId()).matches()) {
+            return;
+        }
+
+        String avatarHash = getJsonProperty(profile, "avatar");
+        if (avatarHash == null || avatarHash.isEmpty() || !AVATAR_HASH_PATTERN.matcher(avatarHash).matches()) {
+            return;
+        }
+        String extension = "png";
+        if (avatarHash.startsWith("a_")) {
+            extension = "gif";
+        }
+        String finalURL = String.format(USER_PICTURE_URL, user.getId(), avatarHash, extension);
+        user.setUserAttribute("picture", finalURL);
+        if (profile instanceof ObjectNode objectNodeProfile) {
+            objectNodeProfile.put("picture", finalURL);
+        }
+    }
+
     @Override
     protected BrokeredIdentityContext doGetFederatedIdentity(String accessToken) {
         log.debug("doGetFederatedIdentity()");