Add Group Folders app support (issue #109)

New groupfolders package with a GroupFolders connector (create/rename/delete/
list folders, grant/revoke group access, set group permissions, set quota),
wired into NextcloudConnector. Reimplemented against the current Jakarta-based
code, based on the implementation in Denis Verkhovsky's fork.

The test container now installs the groupfolders app, and TestGroupFolders
exercises the full lifecycle.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: a-schild

Changelog.md

@@ -1,5 +1,12 @@
 # Changelog for nextcloud api
 
+## Version 14.2.0
+- Add support for the Group Folders app: create, rename, delete and list group
+  folders, grant/revoke group access, set group permissions and set the folder
+  quota via the new `GroupFolders` connector and `NextcloudConnector` methods
+  (issue #109). Thanks to Denis Verkhovsky for the original implementation the
+  port is based on.
+
 ## Version 14.1.6
 - 2026-07-24
 - Add optional `expireDate` parameter to `doShare` / `doShareAsync`, so an

src/main/java/org/aarboard/nextcloud/api/NextcloudConnector.java

@@ -31,6 +31,8 @@
 import org.aarboard.nextcloud.api.filesharing.ShareType;
 import org.aarboard.nextcloud.api.filesharing.SharesXMLAnswer;
 import org.aarboard.nextcloud.api.filesharing.SingleShareXMLAnswer;
+import org.aarboard.nextcloud.api.groupfolders.GroupFolderInfo;
+import org.aarboard.nextcloud.api.groupfolders.GroupFolders;
 import org.aarboard.nextcloud.api.provisioning.*;
 import org.aarboard.nextcloud.api.utils.*;
 import org.aarboard.nextcloud.api.webdav.Files;
@@ -48,6 +50,7 @@ public class NextcloudConnector implements AutoCloseable {
     private final ConfigConnector cc;
     private final Folders fd;
     private final Files fl;
+    private final GroupFolders gf;
 
     /**
      * 
@@ -110,6 +113,7 @@ public NextcloudConnector(String originalServiceUrl, AuthenticationConfig authen
             cc = new ConfigConnector(this.serverConfig);
             fd = new Folders(this.serverConfig);
             fl = new Files(this.serverConfig);
+            gf = new GroupFolders(this.serverConfig);
 
         } catch (MalformedURLException e) {
             throw new IllegalArgumentException(e);
@@ -131,6 +135,7 @@ public NextcloudConnector(String serverName, boolean useHTTPS, int port,
         cc = new ConfigConnector(this.serverConfig);
         fd = new Folders(this.serverConfig);
         fl = new Files(this.serverConfig);
+        gf = new GroupFolders(this.serverConfig);
     }
 
     /**
@@ -189,6 +194,84 @@ public void shutdown() throws IOException {
         ConnectorCommon.shutdown();
     }
 
+    /**
+     * Creates a new group folder (Group Folders app must be installed).
+     *
+     * @param mountPoint name/mount point of the group folder
+     * @return the id of the newly created group folder
+     */
+    public int createGroupFolder(String mountPoint) {
+        return gf.createGroupFolder(mountPoint);
+    }
+
+    /**
+     * Renames (changes the mount point of) a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     * @param newMountPoint new name/mount point
+     */
+    public void renameGroupFolder(int groupFolderId, String newMountPoint) {
+        gf.renameGroupFolder(groupFolderId, newMountPoint);
+    }
+
+    /**
+     * Deletes a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     */
+    public void deleteGroupFolder(int groupFolderId) {
+        gf.deleteGroupFolder(groupFolderId);
+    }
+
+    /**
+     * @return all group folders visible to the current user
+     */
+    public Collection<GroupFolderInfo> getGroupFolders() {
+        return gf.getGroupFolders();
+    }
+
+    /**
+     * Grants a group access to a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     * @param group         group id to grant access to
+     */
+    public void grantAccessToGroupFolder(int groupFolderId, String group) {
+        gf.grantAccess(groupFolderId, group);
+    }
+
+    /**
+     * Revokes a group's access to a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     * @param group         group id to revoke access from
+     */
+    public void revokeAccessToGroupFolder(int groupFolderId, String group) {
+        gf.revokeAccess(groupFolderId, group);
+    }
+
+    /**
+     * Sets the permissions a group has on a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     * @param group         group id
+     * @param permissions   permission bit mask (1 = read, 2 = update, 4 =
+     *                      create, 8 = delete, 16 = share, 31 = all)
+     */
+    public void setGroupFolderPermissions(int groupFolderId, String group, int permissions) {
+        gf.setGroupPermissions(groupFolderId, group, permissions);
+    }
+
+    /**
+     * Sets the quota of a group folder.
+     *
+     * @param groupFolderId id of the group folder
+     * @param quota         quota in bytes, or {@code -3} for an unlimited quota
+     */
+    public void setGroupFolderQuota(int groupFolderId, long quota) {
+        gf.setQuota(groupFolderId, quota);
+    }
+
     /**
      * Close the HTTP client. Perform this to cleanly shut down this
      * application.

src/main/java/org/aarboard/nextcloud/api/groupfolders/GroupFolderAnswer.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2026 a.schild
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.aarboard.nextcloud.api.groupfolders;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import org.aarboard.nextcloud.api.utils.JsonAnswer;
+
+/**
+ * Answer of the "create group folder" call, carrying the id of the new folder.
+ */
+public class GroupFolderAnswer extends JsonAnswer {
+
+    @JsonProperty
+    private Data data;
+
+    @JsonIgnore
+    public Integer getId() {
+        if (data != null) {
+            return data.id;
+        }
+        return null;
+    }
+
+    public static class Data {
+        @JsonProperty
+        public Integer id;
+    }
+}

src/main/java/org/aarboard/nextcloud/api/groupfolders/GroupFolderInfo.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2026 a.schild
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.aarboard.nextcloud.api.groupfolders;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import java.util.Map;
+
+/**
+ * Information about a single group folder as returned by the
+ * <a href="https://github.com/nextcloud/groupfolders">Group Folders</a> app.
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class GroupFolderInfo {
+
+    @JsonProperty
+    private Integer id;
+    @JsonProperty
+    private String mount_point;
+    @JsonProperty
+    private Map<String, Integer> groups;
+    @JsonProperty
+    private Long quota;
+
+    /**
+     * @return the id of the group folder
+     */
+    @JsonIgnore
+    public Integer getId() {
+        return id;
+    }
+
+    /**
+     * @return the mount point (name) of the group folder
+     */
+    @JsonIgnore
+    public String getMountPoint() {
+        return mount_point;
+    }
+
+    /**
+     * @return the assigned groups mapped to their permission bit mask
+     */
+    @JsonIgnore
+    public Map<String, Integer> getAssignedGroups() {
+        return groups;
+    }
+
+    /**
+     * @return the quota of the group folder in bytes, or {@code -3} for an
+     * unlimited quota (see the Group Folders app documentation)
+     */
+    @JsonIgnore
+    public Long getQuota() {
+        return quota;
+    }
+}