add extra fields support to oAuth AccessTokenResponse

Signed-off-by: Laurent ARNAL <laurent@clae.net>

Author: lo92fr

bundles/org.openhab.core.auth.oauth2client/src/main/java/org/openhab/core/auth/oauth2client/internal/OAuthConnector.java

@@ -37,6 +37,7 @@
 import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.util.Fields;
 import org.openhab.core.auth.client.oauth2.AccessTokenResponse;
+import org.openhab.core.auth.client.oauth2.AccessTokenResponseExtraFieldsAdapterFactory;
 import org.openhab.core.auth.client.oauth2.OAuthException;
 import org.openhab.core.auth.client.oauth2.OAuthResponseException;
 import org.openhab.core.io.net.http.HttpClientFactory;
@@ -120,7 +121,7 @@ public OAuthConnector(HttpClientFactory httpClientFactory, @Nullable Fields extr
                     } catch (DateTimeParseException e) {
                         return LocalDateTime.parse(json.getAsString()).atZone(ZoneId.systemDefault()).toInstant();
                     }
-                }).create();
+                }).registerTypeAdapterFactory(new AccessTokenResponseExtraFieldsAdapterFactory()).create();
     }
 
     /**

bundles/org.openhab.core/src/main/java/org/openhab/core/auth/client/oauth2/AccessTokenResponse.java

@@ -15,6 +15,8 @@
 import java.io.Serial;
 import java.io.Serializable;
 import java.time.Instant;
+import java.util.Collections;
+import java.util.Map;
 import java.util.Objects;
 
 /**
@@ -102,6 +104,21 @@ public final class AccessTokenResponse implements Serializable, Cloneable {
      */
     private Instant createdOn;
 
+    /**
+     * Extra element that possibly pass in the token by specific oAuth implementation
+     *
+     *
+     */
+    private Map<String, String> extraFields = Collections.emptyMap();
+
+    public Map<String, String> getExtraFields() {
+        return extraFields;
+    }
+
+    public void setExtraFields(Map<String, String> extraFields) {
+        this.extraFields = extraFields;
+    }
+
     /**
      * Calculate if the token is expired against the given time.
      * It also returns true even if the token is not initialized (i.e. object newly created).

bundles/org.openhab.core/src/main/java/org/openhab/core/auth/client/oauth2/AccessTokenResponseExtraFieldsAdapterFactory.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2010-2026 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.auth.client.oauth2;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+
+public final class AccessTokenResponseExtraFieldsAdapterFactory implements TypeAdapterFactory {
+
+    private static final Set<String> KNOWN_FIELDS = Set.of("access_token", "token_type", "expires_in", "refresh_token",
+            "scope", "state");
+
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+        if (!AccessTokenResponse.class.isAssignableFrom(type.getRawType())) {
+            return null;
+        }
+
+        final TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
+        final TypeAdapter<JsonElement> elementAdapter = gson.getAdapter(JsonElement.class);
+
+        return new TypeAdapter<>() {
+
+            @Override
+            public void write(JsonWriter out, T value) throws IOException {
+                delegate.write(out, value);
+            }
+
+            @Override
+            public T read(JsonReader in) throws IOException {
+                JsonElement tree = elementAdapter.read(in);
+                if (tree != null) {
+                    JsonObject obj = tree.getAsJsonObject();
+
+                    T parsed = delegate.fromJsonTree(tree);
+                    AccessTokenResponse response = (AccessTokenResponse) parsed;
+
+                    Map<String, String> extras = new HashMap<>();
+                    for (Map.Entry<String, JsonElement> entry : obj.entrySet()) {
+                        String key = entry.getKey();
+                        if (KNOWN_FIELDS.contains(key)) {
+                            continue;
+                        }
+                        extras.put(key, toStringValue(gson, entry.getValue()));
+                    }
+
+                    if (response != null) {
+                        response.setExtraFields(extras);
+                    }
+                    return parsed;
+                }
+                return null;
+            }
+        };
+    }
+
+    private static String toStringValue(Gson gson, JsonElement el) {
+        if (el == null || el.isJsonNull()) {
+            return null;
+        }
+        if (el.isJsonPrimitive()) {
+            JsonPrimitive p = el.getAsJsonPrimitive();
+            return p.getAsString();
+        }
+
+        return gson.toJson(el);
+    }
+}