QGIS Server now provides an alternate lastModified() strategy for invalidating the internal project cache, addressing concerns about the ability of QGIS server to invalidate the cache when a project file is updated on atypical file systems, such as NFS, or when the project file is stored in a database system like PostgreSQL.
An asynchronous periodic check strategy using the last modified value of a project is now provided for checking project configuration for changes.
The QGIS_SERVER_PROJECT_CACHE_STRATEGY environment variable may be used to configure the server caching strategy using the following values:
periodic for the alternative strategyfilesystem to use the file system watcher strategyoff to disable internal caching completely.QGIS_SERVER_PROJECT_CACHE_CHECK_INTERVAL is used for controlling the periodic strategy interval.
The QFileSystemWatcher strategy remains the default configuration.